Core Radius Research Articles

Energy equipartition in globular clusters through the eyes of dynamical models

Context. Following their birth, globular clusters (GCs) experience a very peculiar dynamical evolution. Gravitational encounters drive these systems toward energy equipartition, mass segregation, and evaporation, which alter structural, spatial, and kinematic features. Aims. We determine the dynamical state of a few GCs by means of a multi-mass King-like dynamical model. Our work focuses on the prediction of the energy equipartition degree and its relationship with model parameters. Methods. We adjusted the dynamical model parameters in order to reproduce the observed velocity dispersion – as derived from Hubble Space Telescope proper motion data – as a function of the stellar mass. By doing so, we estimated Φ0, a measure of the gravitational potential well. We repeated the same fit by means of the Bianchini relation, a function obtained by interpolating on N-body simulation results. We studied the relationship between Φ0 and the Bianchini equipartition mass meq and discuss the structural properties, such as concentration c, the number of core relaxation timescales Ncore, and core radius rc. To obtain an independent estimate of Φ0, we also fitted observed surface brightness profiles using the predicted surface density and a mass-luminosity relation from isochrones. Results. The quality of the fits of the velocity dispersion–mass relationship obtained by means of our dynamical model is comparable to those obtained with the Bianchini function. Nonetheless, when the Bianchini function is used to fit the projected velocity dispersion, the resulting degree of equipartition is underestimated. On the contrary, our approach provides the equipartition degree at any radial or projected distance by means of Φ0. As a result, a cluster in a more advanced dynamical state shows a larger Φ0, as well as larger Ncore and c, while rc decreases. We find the estimates of Φ0 obtained by fitting surface brightness profiles to be compatible at 2σ confidence level with those from internal kinematics, although further investigation of statistical and systematic errors is required. Conclusions. Our work illustrates the predicting power of dynamical models to determine the energy equipartition degree of GCs. These models are a unique tool for determining structural and kinematic properties, and can be used where observational data are poor, as is the case for the most crowded regions of a cluster, where stars are barely resolved.

The quantum vortices dynamics: spatio-temporal scale hierarchy and origin of turbulence

Abstract This study investigates the evolution and interaction of quantum vortex loops with a small but non-zero radius of core ${\sf a}$. The quantization scheme of the classical vortex system is based on the approach proposed by the author \cite{Tal,Tal_PhRF}. 
 We consider small perturbations in the ring-shaped loops, which include both helical-type shape variations and small excitations of the flow in the vortex core. 
The quantization of the circulation $\Gamma$ is deduced from the first principles of quantum theory. As a result of our approach, the set of quantized circulation values is wider than the standard one.
The developed theory introduces a hierarchical spatio-temporal scale in the quantum evolution of vortices. We also explore the applicability of this model for describing the origins of turbulence in quantum fluid flows. To achieve this specific objective, we employ the method of random Hamiltonians to describe the interaction of quantum vortex loops.

A numerical study on the oscillatory dynamics of tip vortex cavitation

In this paper, we numerically study the mechanism of the oscillatory flow dynamics associated with the tip vortex cavitation (TVC) over an elliptical hydrofoil section. Using our recently developed three-dimensional variational multiphase flow solver, we investigate the TVC phenomenon at Reynolds number $Re = 8.95 \times 10^5$ via dynamic subgrid-scale modelling and the homogeneous mixture theory. To begin, we examine the grid resolution requirements and introduce a length scale considering both the tip vortex strength and the core radius. This length scale is then employed to non-dimensionalize the spatial resolution in the tip vortex region, the results of which serve as a basis for estimation of the required mesh resolution in large eddy simulations of TVC. We next perform simulations to analyse the dynamical modes of tip vortex cavity oscillation at different cavitation numbers, and compare them with the semi-analytical solution. The breathing mode of cavity surface oscillation is extracted from the spatial-temporal evolution of the cavity's effective radius. The temporally averaged effective radius demonstrates that the columnar cavity experiences a growth region followed by decay as it progresses away from the tip. Further examination of the characteristics of local breathing mode oscillations in the growth and decay regions indicates the alteration of the cavity's oscillatory behaviour as it travels from the growth region to the decay region, with the oscillations within the growth region being characterized by lower frequencies. For representative cavitation numbers $\sigma \in [1.2,2.6]$ , we find that pressure fluctuations exhibit a shift of the spectrum towards lower frequencies as the cavitation number decreases, similar to its influence on breathing mode oscillations. The results indicate the existence of correlations between the breathing mode oscillations and the pressure fluctuations. While the low-frequency pressure fluctuations are found to be correlated with the growth region, the breathing mode oscillations within the decay region are related to higher-frequency pressure fluctuations. The proposed mechanism can play an important role in developing mitigation strategies for TVC, which can reduce the underwater radiated noise by marine propellers.

Study on wind load characteristics of gable roof under tornado

This research simulates the behavior of a tornado on a double-slope roof using the Ward tornado generator and the \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SS{T_{k - \\omega }}$$\\end{document} turbulence model. The effects of different ground roughness, slope angle, and wind field position on the tornado load characteristics of gable roofs were studied. The tornado-generating device established the tornado field under various working conditions, and the simulation results were compared with the experimental data to verify the reliability of the simulation results. The wind pressure distribution of gable roofs with four different slope angles was analyzed to find the most unfavorable roof condition of the tornado field. The gable roof’s aerodynamic and wind pressure characteristics at various places in the tornado field were explored by comparing the wind pressure coefficients at five distinct positions on smooth and rough ground. The lift-drag and wind pressure coefficients of five kinds of ground roughness were calculated to determine the influence of different ground roughness on the aerodynamic force and partial pressure distribution of the gable roof. The ground roughness reduces the vortex ratio because the ground roughness reduces the maximum tangential wind speed and the radius of the vortex core. Therefore, the gable roof’s suction increases as the updraft increases.

Magnetic coupling through flux branching of adjacent type-I and -II superconductors in a neutron star

Abstract The inner and outer cores of neutron stars are believed to contain type-I and -II proton superconductors, respectively. The type-I superconductor exists in an intermediate state, comprising macroscopic flux-free and flux-containing regions, while the type-II superconductor is flux-free, except for microscopic, quantized flux tubes. Here, we show that the inner and outer cores are coupled magnetically, when the macroscopic flux tubes subdivide dendritically into quantized flux tubes, a phenomenon called flux branching. An important implication is that up to ∼1012(r1/106 cm) erg of energy are required to separate a quantized flux tube from its progenitor macroscopic flux tube, where r1 is the length of the macroscopic flux tube. Approximating the normal-superconducting boundary as sharp, we calculate the magnetic coupling energy between a quantized and macroscopic flux tube due to flux branching as a function of, f1, the radius of the type-I inner core divided by the radius of the type-II outer core. Strong coupling delays magnetic field decay in the type-II superconductor. For an idealised inner core containing only a type-I proton superconductor and poloidal flux, and in the absence of ambipolar diffusion and diamagnetic screening, the low magnetic moments (≲ 1027 G cm3) of recycled pulsars imply f1 ≲ 10−1.5.

Simulated analogues I: apparent and physical evolution of young binary protostellar systems

ABSTRACT Protostellar binaries harbour complex environment morphologies. Observations represent a snapshot in time, and projection and optical depth effects impair our ability to interpret them. Careful comparison with high-resolution models that include the larger star-forming region can help isolate the driving physical processes and give context in the time domain to the observations. We carry out four zoom-in simulations with au scale resolution that result in three binaries and a single star. For the first time ever, we follow the detailed evolution of a protobinary in a full molecular cloud context until a circumbinary disc forms. We investigate the gas dynamics around the young stars and extract disc sizes. Using radiative transfer, we obtain the evolutionary tracer Tbol of the binary systems. We find that the centrifugal radius in prestellar cores is a poor estimator of the resulting disc size due to angular momentum transport at all scales. For binaries, the disc sizes are regulated periodically by the binary orbit, having larger radii close to the apastron. The bolometric temperature differs systematically between edge-on and face-on views and shows a high-frequency time dependence correlated with the binary orbit and a low-frequency time dependence with larger episodic accretion events. These oscillations can cause the appearance of the system to change rapidly from class 0 to class I and, for short periods, even bring it to class II. The highly complex structure in early stages, as well as the binary orbit itself, affects the classical interpretation of protostellar classes, and the direct translation to evolutionary stages has to be done with caution and include other evolutionary indicators such as the extent of envelope material.

Diet and size at birth affect larval rockfish condition and survival

Feeding success and maternal effects on larval size have long been hypothesized to be important contributors to interannual recruitment variability in marine fishes. This study examined the feeding ecology and influences of diet and size at birth on length and growth of larval rockfishes (Sebastes spp.). Prey carbon biomass and selection were calculated from gut contents, size at birth was estimated using otolith core size, and recent growth was derived from outer otolith increment widths. Biomass contributions of preferred prey and otolith data were integrated into Bayesian hierarchical models predicting length and growth. Larvae primarily fed on and selected for copepod nauplii and calanoid copepodites, modulating feeding with ontogeny and in response to prey availability. Based on carbon weight, the relative contribution of calanoid copepodites to the diet was more strongly and positively correlated with length and growth than that of nauplii. Younger larvae experienced faster growth in association with calanoid copepodite consumption than older larvae. Positive effects of core radius suggest that initial larval size, believed to be mediated by maternal provisioning, increases the likelihood of survival, larger size, and faster growth. These findings ultimately provide evidence that selective feeding and size at birth mediate rockfish survival in early life stages.

A Stochastic FRET Study on the Core Dimension of Polystyrene-block-Poly(Polyethylene Glycol Monomethyl Ether Acrylate) Micelles.

Polystyrene-b-poly(polyethylene glycol monomethyl ether acrylate) (PSt-b-PPEGA) copolymers featuring pyrene and perylene as the Förster resonance energy transfer (FRET) donor (denoted as D-BCP) and acceptor (denoted as A-BCP), respectively, were synthesized via the reversible addition and fragmentation chain transfer (RAFT) polymerization. These copolymers were then used to form DA-mixed micelles via a dialysis method. The micelles consisted of D-BCP (mole fraction fD = 0.04), A-BCP (fA = 0.04), and label-free PSt-b-PPEGA (fN = 0.92). The decrease in fluorescence intensity of pyrene in the micelles confirmed the occurrence of FRET, with an observed efficiency of 0.32. A Monte Carlo approach was employed to estimate the expected FRET efficiency, assuming the random fractional distribution of D-BCP and A-BCP, along with the random spatial distribution of pyrene and perylene within the micellar core. The observed FRET efficiency suggested a core radius (Rc) of 0.95R0, where R0 was the Förster critical distance. With R0 calculated to be 3.2 nm based on Förster theory, Rc was determined to be approximately 3.0 nm, aligning closely with the dried-out core radius estimated from aggregation number and polystyrene density. This stochastic FRET methodology was further applied to investigate the swelling behavior of the polymer micelles in a mixture of N,N-dimethylformamide (DMF) and water. Dynamic light scattering analysis revealed minimal change in core dimension below 60 vol % DMF content. However, FRET analysis provided a deeper insight, showing an increase in core radius with DMF content up to 20 vol %, followed by saturation up to 50 vol %, offering a more comprehensive understanding of the micelle swelling behavior.

Optical fiber with varied flat chromatic dispersion

This paper investigates the design and properties of the conventional all-solid silica based flat dispersion specialty optical fiber. The design utilizes depressed-clad type of refractive index profile which allows for precise control of the optical fiber modal properties, particularly the chromatic dispersion. Specifically designing the dopants concentrations and depressed clad to core diameter ratio allows to obtain optical fibers with flat chromatic dispersion ranging from anomalous to normal dispersion regime. The regime and the values of chromatic dispersion in optical fibers is obtained through the change of the core diameter with the refractive index profile being the same in all optical fibers. The influence of the dopant choice on the mechanical and optical properties is shown using finite element method (FEM) studies. The study demonstrates that fluorine is a better candidate than boron for optical fiber designs that require precise chromatic dispersion characteristics. Six optical fibers were manufactured with the same refractive index profile differing with core radius. This allowed to obtain optical fibers that have chromatic dispersion in anomalous region (17.82 ps/(nm∙km) at 1.96 µm) for the fiber DCFDF1 and normal region (−115.14 ps/(nm∙km) at 1.57 µm) for the fiber DCFDF6.

Wheel path planning for flute grinding of non-cylindrical solid end-mills based on circular arc projection

Flute grinding is a crucial process in solid end-mill manufacturing, because the generated flute parameters, i.e. helix angle, rake angle, core radius, and flute width, have significant effects on the cutting performance of end-mills. However, the flute grinding of non-cylindrical solid end-mills is still challenging due to the variation of the flute parameters along the tool axis. This paper proposes an accurate and efficient method of wheel path planning for flute grinding of non-cylindrical solid end-mills based on circular arc projection. The wheel path determined by the new method can accurately generate the designed helix angle, rake angle, core radius, and flute width, even if all of these parameters vary along the tool axis. The helix angle and rake angle are ensured by the conjugate condition between the wheel surface and the cutting-edge curve. Based on circular arc projection, equivalent errors of the core radius and flute width are introduced to quantify the machining errors of the two parameters, without the need to predict the flute profile. Simulations and experiments are conducted to validate the proposed method. Three types of non-cylindrical end-mills i.e. tapered end-mill, tapered barrel end-mill, and barrel end-mill, are considered in the validation. The measured results indicate that the generated flute parameters coincide well with the designed ones at different axial positions of the end-mills.

The impact of asteroseismically calibrated internal mixing on nucleosynthetic wind yields of massive stars

Context. Asteroseismology gives us the opportunity to look inside stars and determine their internal properties, such as the radius and mass of the convective core. Based on these observations, estimations can be made for the amount of the convective boundary mixing and envelope mixing of such stars and for the shape of the mixing profile in the envelope. However, these results are not typically included in stellar evolution models. Aims. We aim to investigate the impact of varying convective boundary mixing and envelope mixing in a range based on asteroseismic modelling in stellar models up to the core collapse, both for the stellar structure and for the nucleosynthetic yields. In this first study, we focus on the pre-explosive evolution and we evolved the models to the final phases of carbon burning. This set of models is the first to implement envelope mixing based on internal gravity waves for the entire evolution of the star. Methods. We used the MESA stellar evolution code to simulate stellar models with an initial mass of 20 M⊙ from zero-age main sequence up to a central core temperature of 109 K, which corresponds to the final phases of carbon burning. We varied the convective boundary mixing, implemented as ‘step-overshoot’, with the overshoot parameter (αov) in the range 0.05−0.4. We varied the amount of envelope mixing (log(Denv/cm2 s−1)) in the range 0−6 with a mixing profile based on internal gravity waves. To study the nucleosynthesis taking place in these stars in great detail, we used a large nuclear network of 212 isotopes from 1H to 66Zn. Results. Enhanced mixing according to the asteroseismology of main-sequence stars, both at the convective core boundary and in the envelope, has significant effects on the nucleosynthetic wind yields. This is especially the case for 36Cl and 41Ca, whose wind yields increase by ten orders of magnitude compared to those of the models without enhance envelope mixing. Our evolutionary models beyond the main sequence diverge in yields from models based on rotational mixing, having longer helium-burning lifetimes and lighter helium-depleted cores. Conclusions. We find that the asteroseismic ranges of internal mixing calibrated from core hydrogen-burning stars lead to similar wind yields as those resulting from the theory of rotational mixing. Adopting the seismic mixing levels beyond the main sequence, we find earlier transitions to radiative carbon burning compared to models based on rotational mixing because they have lower envelope mixing in that phase. This influences the compactness and the occurrence of shell mergers, which may affect the supernova properties and explosive nucleosynthesis.

A Method for Real-Time Measurement of the Vertical Vortex at Flood Discharge Outlets Using Ultrasonic Sensors.

In this study, ultrasonic sensors were used to measure the vertical vortex at flood discharge outlets in real time, and numerical simulations and model experiments were conducted. When a sound signal passes through a vortex, its propagation characteristics will change, which helps to determine the existence of the vortex. Moreover, its characteristic parameters can be obtained through inversion. In this paper, first, the theories of acoustic measurement methods were introduced and their feasibility was verified through a comparison between Particle Image Velocimetry (PIV) measurement and numerical simulation results. Then, the Computational Fluid Dynamics (CFD) method was used to simulate the vertical vortex at the flood discharge outlets of hydraulic structures and the simulation data were restored to the actual size at scale. Finally, acoustic numerical simulations of actual vortex data were conducted, and ultrasonic sensors were used to measure the velocity of a simplified vertical vortex model under laboratory conditions. The research results indicate that the acoustic measurement method proposed in this article is effective in the measurement of the characteristic parameters of vertical vortex with a core radius of 0.03~0.05 m and a maximum tangential velocity of 0.5 m/s, the measurement error of the maximum tangential velocity is within 10%.

Galactic dynamics in the presence of scalaron: a perspective from f(R) gravity

We consider f(R) modified gravity theory incorporating the chameleon mechanism to address galactic dynamics. By employing the metric formalism and utilizing a conformal transformation, we simplify the field equations and describe the extra degree of freedom f R via a scalar field (scalaron) with chameleonic behavior. A recently proposed f(R) model is analyzed to illustrate this behavior effectively. Subsequently, the rotational velocity equation including the scalaron’s contribution is derived for a test particle in a static, spherically symmetric spacetime. Then we generate rotation curves and fit them to observational data of thirty seven galaxies using two fitting parameters, M 0 and r c , the total mass and core radius of a galaxy respectively.

Characterization of tornado-induced wind pressures on a multi-span light steel industrial building

This study presents the characteristics of external wind pressures of a multi-span light steel industrial building through wind pressure measurements conducted in a tornado simulator. The test model is designed as a three-span low-rise building with gable roofs according to the practical measured sizes and shapes of the light steel industrial building destroyed in the Shengze tornado, China (2021). The distance from the tornado-like vortex center to the building, building orientation, roof angle, and swirl ratio are considered as experimental parameters. The effects of the parameters on the most unfavorable peak and mean pressure coefficients of each surface are analyzed. The roof zoning specified in ASCE 7–16 was re-analyzed based on the characteristics of wind pressure coefficients, and the tornado design pressure coefficients were calculated. The results of the analysis illustrate that the wind-ward roof surface at a distance of around one vortex core radius from the center experience the most severe pressure coefficient under tornado, the most unfavorable zone of the pressure coefficients on the building roof changes with the building orientation, the model with a smaller roof angle has smoother pressure coefficient contours than that with a larger roof angle because of the cutting effect of the ridge, and the simulated tornado with the lower swirl ratio generate higher external pressure coefficients on the building model. Moreover, the roof zoning in ASCE 7–16 for the boundary layer wind is not precise for tornado, thus an updated roof zoning for the tornado design pressure coefficients is defined.

Investigations on the Effects of Bonding and Forming Conditions on the Deformation Behavior of Copper-Steel Bimetallic Rods during the Cold Drawing Processes.

Metal composite parts are widely used in different industries owing to their significant improvement in material properties, such as mechanical strength, electrical conductivity, and corrosion resistivity, compared to traditional single metals. Such composite parts can be manufactured and processed in different ways to achieve the desired geometry and quality. Among various metal forming techniques, drawing is the most commonly used process to produce long composite wires or rods from raw single materials. During the drawing process of composite wires or rods, not only does the core radius ratio change, but the core or sleeve layer may also undergo necking or fracture due to excessive tensile stresses in the softer layer. In this paper, bimetallic rods with AISI-1006 low-carbon steel cores and C10100 oxygen-free electronic copper sleeves are modeled using the finite element software DEFORM. The simulation models are verified by drawing experiments. The effects of initial bonding conditions, the initial core ratio, reduction ratio, semi-die angle, drawing speed, and friction on the plastic deformation behavior of the bimetallic rods are investigated. The results indicate that the initial bonding conditions have a great impact on the deformation behavior of the billets in terms of strain distribution, material flow, residual stress, and the final core ratio. The permissible forming parameters for obtaining a sound product are investigated as well. With the aid of these analyses, the drawing process and the quality of the products can be controlled steadily.

The combined effects of electric field and embedded dielectric matrix on the electronic and optical properties in Ge/SiGe core/shell quantum dots and its SiGe/Ge inverted structure

In this study, the binding energy (BE) and photoionization cross-section (PICS) coefficients in a Ge/Si0.15Ge 0.85 core/shell quantum dots (CSQDs) and in its inverted structure Si0.15Ge0.85 / Ge (ICSQDs) are studied. The influence of the hydrogenic impurity and capped matrix are taken into account. The electronic states and their related eigenfunctions are computed by solving the three-dimensional Schrödinger equation under the framework of the effective mass approximation (E.M.A) using the variational dimensional. The influence of the core radius and electric field strength on the BE and PICS are investigated. The numerical results reveal that the optoelectronic properties are considerably affected by the electric field strength (EF), immersed oxide matrix (OM) and geometric parameter. The obtained results prove that the PICS magnitude increases as the core radius increases and its resonant peak moves towards the lower energies for Ge/Si0.15Ge0.85 CSQDs structure, and increases as the core radius decreases and its resonant peak experiences a blue shift with increasing core radius for Si0.15Ge 0.85/ Ge ICSQDs. Moreover, with the effects of the surrounding oxide matrix and electric field strength, the PICS magnitude is improved and their resonant peak suffers a redshift.

UOCS XIV: Study of the Open Cluster NGC 2627 Using UVIT/AstroSat

We study the intermediate-age open cluster NGC 2627, located at a distance of ∼2 kpc, using UVIT/AstroSat and other archival data. Using a machine learning-based algorithm, ML-MOC, on the Gaia DR3 data, we identify 422 cluster members, including four blue straggler stars (BSSs), one yellow straggler star (YSS), one blue lurker (BL), one red clump (RC) star, and two binary candidates with detection in both UVIT/F148W and UVIT/F169M filters. We characterise them using multiwavelength spectral energy distributions (SEDs). Out of the above nine sources, one BSS, the BL, and one binary candidate have a source nearby; hence, we did not fit their SEDs. Of the remaining six sources, we successfully fit two with single-component SEDs and four with binary-component SEDs. The binary-component SED-based parameters indicate that the hot companions of BSSs, the YSS, the RC star, and the binary candidate are extremely low-mass white dwarfs, confirming that at least four out of nine stars (44%) are formed via the mass transfer channel. We fit King’s profile function to the high-probability (p > 0.8) cluster members and estimate the cluster core radius (r C ) to be 3.84′ and the tidal radius (r t ) to be 36.85′. We find that the equal-mass binaries are most concentrated towards the cluster center, followed by the single massive stars, and single low-mass stars. The BSS population of the cluster is also found to be located within a radius r ∼ 10 × r C from the cluster center, suggesting the dynamical evolution of the cluster.

Detailed scrutiny of FWM in holmium-doped fiber amplifier (HOFA) in WDM systems

Abstract Four wave mixing (FWM) in wavelength division multiplexed (WDM) systems is prominent performance degrading nonlinearity and limits the total capacity of the system. FWM is explored in different fiber optical amplifiers such as erbium-doped fiber amplifier (EDFA), Raman fiber amplifier (RFA), and also in semiconductor optical amplifier (SOA). Reported studies in HOFA revealed that nonlinear effects in these amplifiers are low; however, in present study, in this research article WDM-HOFA system has been simulated and studied FWM in detail at different HOFA parameters such as input power, length, core radius, doping radius, numerical aperture (NA), Ho ion density, and effects of co- and counter-pumping. Gain and noise figure (NF) are also investigated at aforementioned parameters, and performance is evaluated in terms of optical signal to noise ratio (OSNR) at 2,030 nm wavelength window. It is observed that least FWM obtained at 3 m Ho fiber length, 2 µm core radius and doping radius, 15.6 × 1023 m−3 Ho ion doping, 0.1 NA, −10 dB input power, 0.8 GHz channel spacing, and 4 WDM channels. However, better gain and NF comes at different values of these parameters, and as a result, there is trade-off between FWM and gain, NF.

Estimation of the injection criteria for magnetic hyperthermia therapy based on tumor morphology

Intratumoral multi-injection strategy enhances the efficacy of magnetic nanoparticle hyperthermia therapy (MNPH). In this study, criteria for the selection of injections and their location depending on the tumor shape/geometry are developed. The developed strategy is based on the thermal dosimetry results of different invasive 3D tumor models during MNPH simulation. MNPH simulations are conducted on physical tumor tissue models encased within healthy tissue. The tumor shapes are geometrically divided into a central tumor region containing maximum tumor volume and a peripheral tumor portion protruding in any random direction. The concepts of core and invasive radius are used to geometrically divide the tumor volume. Primary & secondary injections are used to inject MNP fluid into these respective tumor regions based on the invasiveness of the tumor. The optimization strategy is devised based on the zone of influence of primary & secondary injection. Results indicate that the zone of influence of secondary injection lies between 0.7 and 0.8 times the radial distance between the center of the tumor core and branch node point (extreme far endpoint on the invasive tumor surface). Additionally, the multi-injection strategy is more effective when the protrusion volume exceeds 10% of the total volume. The proposed algorithm is used to devise multi-injection strategies for arbitrarily shaped tumors and will assist in pre-planning magnetic nanoparticle hyperthermia therapy.

Management of lateral misalignment loss and total insertion loss with beam waist control in high contrast single mode coupling fibers

Abstract This paper has illustrated the management of lateral misalignment loss and total insertion loss with beam waist control in high contrast single mode coupling fibers. The beam waist variations are clarified versus the fiber coupler wavelength and coupling length variations for the silica glass/fluoride glass fiber coupler with the optimum incident beam angle of 60°. Besides, the coupling loss is demonstrated against the fiber coupler wavelength and coupling length variations for the silica glass/fluoride glass fiber coupler with the optimum incident beam angle of 60°. The optimum beam waist and optimum coupling loss are deeply studied against the fiber coupler core radius variations for the silica/fluoride glass fiber coupler with the optimum incident beam angle of 60° and wavelength of 1,550 nm.