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Magnetic nano-particles are used in medicine both as medical means, and for the transport of medicines in the pathological area of an organism. Simultaneous influence on these particles of ultrasonic radiation and a constant magnetic field allows summarising a magnetic field of an nano-particles ensemble to the value, sufficient for its registration by the remote magnetic detector. The parity connecting the measured magnetic flux of the nanoparticles with parameters of the particles, ultrasound, and the measuring system using as the magnetic detector superconducting quantum magnetometer is received. Calculations have shown, that such a system can measure a concentration of the nano-particles in colloidal solution, modeling the biological medium, in the unattainable earlier dynamic range of values (from 1 vol % to 10−7 vol %).

Diffusion Magnetic Resonance Imaging (MRI) plays a very important role in studying biological tissue cellular structure and functioning both in health and disease. Proper interpretation of experimental data requires the development of theoretical models that connect the diffusion MRI signal to salient features of tissue microstructure at the cellular level. In this short review, we present some theoretical approaches to describing diffusion-attenuated magnetic resonance signals. These range from the models based on statistical properties of water molecules diffusing in the tissue- cellular environment, to models allowing exact analytical calculation of the magnetic resonance signal in a specific single-compartment environment. Such theoretical analysis gives important insights into mechanisms contributing to the formation of diffusion magnetic resonance signal and its connection to biological tissue cellular structure.

Laser-driven ion beams have gained considerable attention for their potential use in multidisciplinary research and technology. Preclinical studies into their radiobiological effectiveness have established the prospect of using laser-driven ion beams for radiotherapy. In particular, research into the beneficial effects of ultrahigh instantaneous dose rates is enabled by the high ion bunch charge and uniquely short bunch lengths present for laser-driven ion beams. Such studies require reliable, online dosimetry methods to monitor the bunch charge for every laser shot to ensure that the prescribed dose is accurately applied to the biological sample. In this paper, we present the first successful use of an Integrating Current Transformer (ICT) for laser-driven ion accelerators. This is a noninvasive diagnostic to measure the charge of the accelerated ion bunch. It enables online estimates of the applied dose in radiobiological experiments and facilitates ion beam tuning, in particular, optimization of the laser ion source, and alignment of the proton transport beamline. We present the ICT implementation and the correlation with other diagnostics, such as radiochromic films, a Thomson parabola spectrometer, and a scintillator.

In this study, we perform a numerical analysis of the instability of a ligament in shear flow and investigate the effects of air-liquid shear on the growth rate of the ligament interface, breakup time, and droplet diameter formed by the breakup. The ligament is stretched in the flow direction by the shearing of airflow. Furthermore, as the influence of the shear flow increases, the ligament becomes deformed into a liquid sheet, and a perforation forms at the center of the liquid sheet. The liquid sheet breaks up due to the growth of the perforation and contracts under the influence of surface tension, forming two ligaments with diameters smaller than that of the original ligament. The shearing of the airflow causes the original ligament to elongate, and the cross-section of the ligament becomes elliptical, which increases instability. As a result, the growth rate of the ligament exceeds the theoretical value, and increases with increasing wavenumber of the initial disturbance. Therefore, the diameter of the formed droplets in shear flow decreases due to the increase in the wavenumber that governs the breakup of the ligament, and because the growth rate increases, the breakup time for the ligament decreases. As the velocity difference of the shear flow increases, constrictions of the ligament form earlier and the diameter of the satellite droplet increases. As the diameter of the satellite droplet increases and that of the main droplet decreases, the dispersion of the droplet diameter decreases, making the diameter uniform., 22 pages, 15 figures, 1 table

The effect of irradiation with high-energy electrons on the transverse electrical resistivity of YBa2Cu3O7–δ single crystals with a high degree of perfection that are optimally doped with oxygen is considered. This irradiation creates macroscopic regions oriented along the layers in the sample, which are characterized by oxygen deficiency, leading to variable-range hopping transverse conductivity. An increase in the dose of irradiation leads to a decrease in the region of localization of charge carriers.The effect of irradiation with high-energy electrons on the transverse electrical resistivity of YBa2Cu3O7–δ single crystals with a high degree of perfection that are optimally doped with oxygen is considered. This irradiation creates macroscopic regions oriented along the layers in the sample, which are characterized by oxygen deficiency, leading to variable-range hopping transverse conductivity. An increase in the dose of irradiation leads to a decrease in the region of localization of charge carriers.

In this study, a nondestructive ring-shaped laser ultrasonic method with a thermoelastic excitation regime was used to determine the grain size of metal materials. This method was proposed in order to evaluate the quality of metal in a fast online nondestructive manner. Normally, laser ultrasonic is used to detect grain size in the ablation excitation regime. The laser excites high energy longitudinal waves but causes damage to the surface of metal materials. To achieve strict online nondestructive testing, the thermoelastic regime was used in this work. The ring-shaped laser was converted from a circular collimated laser by an axicon and irradiated on the surface of the aluminum sample to induce ultrasonic waves and enhance the signal amplitude. The directivity pattern was analyzed to find a suitable detection parameter by the finite element method before performing laser ultrasound experiments. Quantitative analysis of the converging waves with different deviations from the center via laser ultrasound experiments demonstrated the enhancement effect of signal energy using a ring-shaped laser. The issues of low signal energy and the generation of a directivity pattern were solved by this ring-shaped laser ultrasonic method aimed at nondestructive grain size inspection. Aluminum samples with different mean grain sizes were detected by ring-shaped laser ultrasonic technology. A grain size characterization model was built with mean grain sizes and ultrasonic signals. Laser-generated ultrasound technology in the thermoelastic regime is a promising online detection method and can be used to detect material properties nondestructively with a ring-shaped laser.

The flow and saliva particulate transport dynamics during normal human breathing through the mouth are simulated numerically using an Eulerian large-eddy simulation (LES) approach for the flow coupled with a Lagrangian approach for the transport of saliva particles. The coupled Eulerian–Lagrangian (EL) simulation results reveal new striking insights into the rich dynamics of the Lagrangian coherent structures (LCS) that arise from saliva particles during normal breathing. Specifically, they uncover a new time-periodic mechanism via which particles are introduced into the flow as individual breathing pulses and accumulate to form a slowly propagating vortex front that persists long distances away from the source. The simulated LCS reveal a wealth of recurrent material motion through which the biosols propagate forward while their cloud expands laterally with a slowly evolving vortex front. Also, the finite-time Lyapunov exponent (FTLE) field of human breathing was calculated using the flow map from the LES velocity field. The ridges of the calculated FTLE field revealed distinct hyperbolic LCS, which closely resemble trajectories of saliva particles obtained from the coupled EL simulation. Finally, simulation results for normal breathing with a non-medical face mask show that the mask can effectively disrupt the formation of coherent particle surfaces and, thus, effectively limit saliva particle propagation.

The paper presents a 2D model of a system for contactless inductive energy transmission. Graphical dependences for the inductance of the transmission coil on the frequency, on the magnetic permeability of the concentrators and on the distance between the coils are obtained. In addition, results for the power of the transmitting coil and the dependence of the induced voltage in the receiving coil on the frequency of the power supply are shown. An analytical model of an air transformer is used to explain the numerical results.

In this work, the authors solve some stability problems of quartic functional equation in ℒ – fuzzy normed space(ℒ – FNS) and non-Archimedean ℒ – fuzzy normed space(ℒ – FNS). Also, we generalize the stability results of quadratic functional equation in fuzzy Banach space(FBS) within a any t′ – norm.

In the course of this study extracted teeth filled with materials for endodontic treatment and fragments of broken metal instruments were scanned using cone beam computed tomography and microfocus cone beam computed tomography devices. Comparative evaluation of three-dimensional and two-dimensional tomographic reconstructions was performed. Cone beam computed tomography provided blurred images of hyperdense materials. Microfocus cone beam computed tomography made it possible to describe filling materials in microscopic detail and to create accurate models of metallic fragments.

Carbon ion therapy has several advantages over proton therapy in terms of target depth precision, biological effectiveness, and patient outcome. Despite these advantages, there are far fewer carbon ion therapy facilities in operation around the world compared to proton therapy facilities. The adoption of carbon ion therapy has been severely limited by the cost and size of dedicated infrastructure and facilities in order to accommodate the heavier ion species. The Next Ion Medical Machine Study (NIMMS) project led by CERN aims to design the next generation hadron therapy system including a compact synchrotron and an efficient beam delivery method for future clinical use. In collaboration with CERN, this work presents a comparison of current synchrotron designs used at carbon ion therapy facilities and motivates the need for a new, efficient future design. While normal conducting and superconducting options are being considered, here we propose a compact, normal-conducting synchrotron based on the double-bend achromat structure.

A three-dimensional electronic detector array consisting of an active matrix readout configuration has been designed. The array comprises 31,560 submillimeter size photodiodes isotropically distributed within a 20 cm diameter semi-spherical volume of water equivalent material. The number of photodiodes in an active matrix varies from 27 to 972, and 80 active matrices with 4200 channels are connected to a data acquisition unit for readout. A low resolution 20 cm diameter semi-spherical electronic detector array was constructed to test the active matrix readout configuration response. The array consists of 135 BPW34S photodiodes distributed in a 12 cm diameter layer and one ionization chamber at the center of the semi-spherical volume. Furthermore, a quality assurance plan for a 6-field 6-MV intracranial treatment was generated to check the array's response. The array was dose calibrated using 20 x 20 cm2 parallel-opposed 6 MV photon beams from a Varian 2100 C/D linear accelerator and the integrated voltage from each photodiode was matched to the calculated dose from a treatment planning software for that photodiode location. Data analysis resulted in a percent dose difference between the measured and calculated dose of ≤5%.

For current and future large scale tokamaks, neutral beams for heating and current drive are generated from the neutralisation of large negative ion beams with energies up to 1 MeV and current of up to 40 A. To improve efficiency and prevent high heat loads on beamline components, permanent magnets are used to deflect co-extracted electrons out of the beam at a low energy. This field also affects the negative ions as they are accelerated, causing beamlets to exit the grid system with a residual offset and deflection angle. This adversely affects the overall divergence of the beam, and compensation is foreseen in future devices. Measurements of the residual deflection of a single beamlet have been carried out at the BATMAN Upgrade test facility by calculating relative beamlet angles from beam emission spectroscopy (BES) spectra, and through the use of one-dimensional carbon fibre composite (1D-CFC) tile calorimetry to find beamlet positions. It is described how these measurements can be made, and that they are limited to relative measurements only, for a single beamlet and for a single line of sight. The amount of beamlet deflection is shown to change significantly, by up to 0.6°(10 mrad), depending on the operational parameters used. As is to be expected the beamlet deflection angle is observed to be affected by changes to the voltages of the acceleration system. However, the beamlet deflection angle is also observed to change with RF power and other source parameters, which, to a first approximation, should only affect beamlet divergence, and not the deflection. These changes to beamlet deflection through parameters other than the grid voltages used may have consequences for systems planning to use suppression systems for the zig-zag deflection. The effectiveness of the suppression system may be reduced due to changes in the source parameters, which could lead to beam losses and high heat loads on downstream components.

Rapidly quenched alloys of composition Fe83Sn5B12 and Fe78Co5Sn5B12 were irradiated by electron beam with 4 MGy dose. The aim of the presented study is examination of the influence of irradiation on magnetic properties and microstructure in as-cast and nanocrystallized ribbons. Amorphous samples after irradiation retained their soft magnetic properties and the hysteresis loops obtained a more upright shape with a higher value of saturation magnetic polarization. The Co-containing ribbon is superior in terms of magnetic softness and even after irradiation its saturation polarization is significantly higher with the value of 1.79 T.

The quality of medical images is very important in clinical use, such as clinical diagnosis, pathology analysis, etc. This paper presents a brief survey of the advantages and trends of medical image processing techniques based on multidimensional wavelet transforms as well as their combinations with other methods, which model each coefficient set as a tensor. Unlike the classical wavelet decompositions wavelet tensor modifications has only one parameter to be tuned, which makes the computing easier to use in various medical processing methods such as noise reduction, compression, segmentation, classification, medical image fusion. These methods can be very useful for multidimensional images such as MRI and CT data or for integration and analysis of many types of medical image data.

This paper presents the results of the energy and angular dependence calculations and experimental verification of the military dosimetric device DP-86 probe. This device was designed to measure the gamma radiation dose rate of nuclear weapons fall out, that means the fission products mixture. The beta emission can also be roughly estimated. Based on these results was calculated the time dependence of the device response to nuclear weapon fallout.

Since neutrons especially fast neutron has a high weighting factor in radiation dosimetry, exposing the human’s body to a neutron source in a laboratory or clinic may put body tissues at risk and dangerous situations. In doing so, in this investigation, body tissue together with soft tissues (including adipose and skin) were decomposed into their fundamental elements, and then got emitted by neutrons. This research can be put into operation all tissues about cancer therapy. The amounts of neutron energy because of the collision between neutrons and nuclei of the basic elements got calculated in the tissue Next, some results got concluded. The results imply that the highest transferred energy happens within the energy range 3.5-10.5 MeV and also energy ranges 15-16.5 MeV. As well, the tendencies of the transferred-energy graphs were very in a similar way and are the same as other fundamental elements, and the maximum transferred energy happened for the elements that had a small atomic weight.

Hadrontherapy deals with the maximum energy deposition in the form of Bragg peak for energetic charged particles at a particular depth for killing cancerous cells. For planning hadrontherapy treatment accuracy in transport codes are primary demands of radiation oncology. In this work, we studied the dose deposition of the proton beam for the energy range of clinical interest i.e. 70 MeV to 240 MeV in water considering as tissue-equivalent material. The Bragg peak studies for different energy values are executed using Monte Carlo codes-based toolkit- GEANT4. We compared the four physics lists, the QGSP_BERT, the QBBC, the PhysListEmStandardNR (StandardNR), and emstandard_opt0, present in the Geant4 toolkit for avoiding uncertainty in the determination of dose deposition in the living cells which may cause damage of healthy cells. The StandardNR physics list is found suitable to get localized dose deposition in the form of smooth Bragg Curve.

A temperature recording and storage system was designed and built, consisting of an array of five thermistor-type sensors, coupled to a synthetic model of biological tissue (MRI phantom) for Ultra-Low Field Magnetic Resonance Imaging System (ULF-MRI), using the Atmega328P microcontroller, like data logging and also used to determine the change in temperature associated with the absorption of energy within the phantom due to the interaction between the radio frequency (RF) field with a sample in different regions within it in MRI studies. The changes in temperature during the MRI study was registered for the entered MRI sequence. All the experiments were carried out in a ULF-MRI system Terranova that uses the Earth’s magnetic field to obtain the resonance signal from the magnetization of the protons present in a sample of interest, and thus be able to perform primary imaging and spectroscopy studies [1].

Electro-magneto-hydrodynamic flow of non-Newtonian fluid (blood) suspended with magnetic particles (erythrocytes) through tapered stenosed inclined artery is explored in this study. The fluid is influenced by a pulsatile constant pressure gradient and an inclined magnetic field. Governing partial differential momentum equations are solved and the fluid and particles axial velocity formula is derived in the analytical form. Further, closed form expressions are obtained for wall shear stress, flow resistance and volumetric flow rate. Graphical analysis of various physiological dynamics against embedded parameters is developed by MATLAB coding. Effects of pertinent parameters are examined and results are discussed. It is noted that both fluid and particle velocity profiles are reduced with increasing values of Hartmann number. In contrast, the electrokinetic number increases the velocities of the fluid and particle. Thus, the fluidic flow can be regulated by applying strong and adequate electromagnetic field which plays a vital role in diagnosing cardio vascular diseases and the respective medical care.

Recently, microwave imaging for ultra-wide-band (UWB) has been suggested to detect small breast tumors that are malignant. The microwave imaging technique in-depth is used for biological tissue analysis. The test morphological variations are found in these biological tissues, as well as their location .The approach to microwave imaging is one of the methods of development that, due to its non-ionizing nature, researchers around the world pay attention to early breast cancer screening. Therefore, many variables construction of MIMO antennas is of great importance, it is made of the material from which it begins, its dimensions, operating bandwidth, compared to the new imaging methods, and the opportunity for reductions in costs and simplified processes. The human body’s effect on antenna parameters, short-pulse propagation, etc. In recent years, numerous attempts to improve the electromagnetic sensors used in these devices have been demonstrated. Because of no best-proven bandwidth, in this application, the option of MIMO antennas is crucial. However, the antenna is said to have influenced the resolution of a picture. This article examines the use of MIMO and works for potential antenna production in the early detection of breast cancer.

In this paper, a modified radio frequency (RF) coil version is presented to be suitable to work at 900 MHz. The proposed coil is based on the Petal Surface Coil and Petal Resonator Surface Coil, whose resonant frequencies were 22 MHz and 64 MHz, respectively. These encouraging results at low field motivated the development of a modified petal resonator surface coil for ultra-high field magnetic resonance imaging applications. Electromagnetic field and return loss simulations guided the development of our coil design. Our prototype consisted of six small circular loops whose diameter was 0.5 cm, connected in series and the total coil diameter was 3 cm. Electromagnetic simulations showed the characteristic patterns of the prototype and provided the theoretical grounds to reliably develop this type of RF coils at 900 MHz. Bench tests measurements showed an important agreement with numerical values. It still remains to actually acquire phantom images to test the viability and compatibility with standard procedures for ultra-high field magnetic resonance imaging applications. This coil design may serve to develop coil arrays with improved performance for high frequencies.

Solid-state nuclear magnetic resonance can be enhanced using unpaired electron spins with a method known as dynamic nuclear polarization (DNP). Fundamentally, DNP involves ensembles of thousands of spins, a scale that is difficult to match computationally. This scale prevents us from gaining a complete understanding of the spin dynamics and applying simulations to design sample formulations. We recently developed an ab initio model capable of calculating DNP enhancements in systems of up to ∼1000 nuclei; however, this scale is insufficient to accurately simulate the dependence of DNP enhancements on radical concentration or magic angle spinning (MAS) frequency. We build on this work by using ab initio simulations to train a hybrid model that makes use of a rate matrix to treat nuclear spin diffusion. We show that this model can reproduce the MAS rate and concentration dependence of DNP enhancements and build-up time constants. We then apply it to predict the DNP enhancements in core–shell metal-organic-framework nanoparticles and reveal new insights into the composition of the particles’ shells.

The mechanisms governing cardiac fibrillation remain unclear; however, it most likely represents a form of spatiotemporal chaos with conservative system dynamics. Renewal theory has recently been suggested as a statistical formulation with governing equations to quantify the formation and destruction of wavelets and rotors in fibrillatory dynamics. In this perspective Review, we aim to explain the origin of the renewal theory paradigm in spatiotemporal chaos. The ergodic nature of pattern formation in spatiotemporal chaos is demonstrated through the use of three chaotic systems: two classical systems and a simulation of cardiac fibrillation. The logistic map and the baker's transformation are used to demonstrate how the apparently random appearance of patterns in classical chaotic systems has macroscopic parameters that are predictable in a statistical sense. We demonstrate that the renewal theory approach developed for cardiac fibrillation statistically predicts pattern formation in these classical chaotic systems. Renewal theory provides governing equations to describe the apparently random formation and destruction of wavelets and rotors in atrial fibrillation (AF) and ventricular fibrillation (VF). This statistical framework for fibrillatory dynamics provides a holistic understanding of observed rotor and wavelet dynamics and is of conceptual significance in informing the clinical and mechanistic research of the rotor and multiple-wavelet mechanisms of AF and VF.

A number of annular cylindrical RF-resonators is studied here in the context of serving as a specialized receive-transmit antennas (commonly referred to as coils) in penile magnetic resonance imaging. The intended niche application results in a number of particular requirements to the coils, particularly, strong decoupling from the large lossy body mass in the vicinity of the coil, and high magnetic field homogeneity inside the coil. Three solenoid-based designs and one birdcage-based design are considered for operation at 63.85 MHz in this work. Simulations are performed to assess the influence of the patient body on the quality factor of the coil and the field homogeneity the coils provide. The results show that the birdcage-based design provides higher field homogeneity than solenoid-based designs, while exhibiting similar independence from the patient body.

In this contribution, we investigate the effect of a resonant high-impedance shield as a part of a birdcage coil for human brain imaging at 7 T. On a homogeneous phantom, it was shown that the loading of the birdcage coil to the sample can be enhanced by replacing a conventional copper shield with the high-impedance boundary with frequency-dependent surface impedance. To demonstrate this effect, we perform a numerical simulation of an extended birdcage coil with the high-impedance shield. The extended coil is much more comfortable for a patient and creates a lower local SAR. It has been shown that the extended coil equipped with the high-impedance shield has the same efficiency as a standard-size coil with the copper shield.

In this research we developed an ultra-compact X-ray tubes. The paper presents the results of investigations into the emission and dose characteristics of ultra-compact X-ray tubes. The dose distribution in the anode area along the height and azimuth of the X-ray tube is shown. The data on the dose dependence on time during exposure are illustrated.

Dielectric resonators based on high permittivity materials with low losses have recommended themselves as good candidates for improving magnetic resonance imaging (MRI) characteristics. Mainly due to the ability to focus and enhance the radiofrequency (RF) magnetic field, they are promising alternatives to dedicated cable-connected RF coils. In this work, we investigate a system of coupled, very-high permittivity dielectric resonators for bilateral breast MRI at 3T. The resonators are implemented as a pair of coaxial hollow cylinders consisting of ceramic rings, which are inductively coupled with a birdcage coil of the MRI machine. We investigated the behavior of antisymmetric and symmetric TE-modes of two coupled resonators. Via electromagnetic simulations, we verified that the symmetric mode of coupled dielectric resonators could be effectively excited with birdcage coil, focusing RF magnetic field in the region of interest, thereby realizing targeted MRI concept.

The Energy Sweep Compact Rapid Cycling Hadron driver for future cancer therapies based on the induction synchrotron concept is described. This fast cycling synchrotron that allows the energy sweep beam scanning. Assuming a 1.5 T bending magnet, the ring can deliver heavy ions of 430 MeV/u at 10 Hz. A beam fraction is dropped from the barrier bucket at the desired timing and the increasing negative momentum deviation of this beam fraction becomes enough large for the fraction to fall in the electrostatic septum extraction gap, which is placed at the large D(s) region. The programmed energy sweeping extraction makes spot scanning beam irradiation on a cancer area in depth possible.

This contribution presents a homogenization of the elastic properties of trabecular structures used in modern implantology. Trabecular structures can be characterized as spatial truss structures composed of beams. Their numerical modeling and precise three-dimensional discretization by finite elements usually lead to a huge number of degrees of freedom. One of the possible solutions of this problem can be a homogenization approach based on a two-level analysis, where the specimen, the implant, is discretized by a coarse mesh at the macro-level, and the elements of the trabecular structure are represented by effective (homogenized) material properties obtained from a representative volume element at the meso-level. The application of this multi-scale procedure is illustrated by a numerical simulation of laboratory compression tests of trabecular specimens.

Mathematical modelling is used to investigate the electric field enhancement in various configurations of cuboid gold nanoparticles that are placed on a glass substrate and are irradiated with a plane wave. The influence of the substrate, the nanoparticle dimension, as well as the critical role of the distance between the gold nanoparticles is investigated. Moreover, the cuboid gold nanoparticle optical properties are determined.Mathematical modelling is used to investigate the electric field enhancement in various configurations of cuboid gold nanoparticles that are placed on a glass substrate and are irradiated with a plane wave. The influence of the substrate, the nanoparticle dimension, as well as the critical role of the distance between the gold nanoparticles is investigated. Moreover, the cuboid gold nanoparticle optical properties are determined.

Analysis of Radial vibrations in a two layered poroelastic hollow cylinder loaded and surrounded by inviscid fluids is presented. A poroelastic composite hollow cylinder consists of two concentric cylindrical shells with each one made with different poroelastic materials. The poroelastic materials are assumed as homogeneous and isotropic, whereas the inner and outer fluids are homogeneous, isotropic and inviscid. The frequency equation of Radial vibrations of two layered poroelastic cylindrical shell is derived. The effect of inviscid fluid on Radial vibrations is observed. The frequency equation of fluid-loaded poroelastic composite cylinder surrounded by a fluid is obtained along with several particular cases, namely, fluid-loaded poroelastic composite cylinder, fluid-loaded composite bore, poroelastic composite cylinder surrounded by fluid. Non-dimensional frequency is computed as a function of ratio of thickness to inner radius of core cylinder then discussed. The results are presented graphically for two types of poroelastic composite cylinders and then discussed.

This article presents the microwave imaging techniques in order to detect early lung cancer with dielectric properties of normal and cancerous tissues which affect the propagation of the microwave signal. Identifying the contrast of dielectric properties of normal and cancerous lung tissues is significant in microwave imaging because it is used in reconstructing the image either in radar-based or tomographic imaging techniques. In microwave imaging measurement from past researchers are highlighted in order to identify the optimum distance of the antenna from the human thorax and the significant size of the tumour that can be detectable.

Numerical simulation of cavitating flow was performed for turbopump inducers with three blades with a backward sweep and different inlet blade angle. The computation was carried out by solving the Reynolds averaged Navier-Stokes equations with a homogenous cavitation model and k-ω turbulence model. Numerical results concerning inducer characteristics and performance curves were compared with experimental results at difference flow coefficients and cavitation numbers. The occurrence of cavitation and its spatial distribution in each inducer were also investigated. As the result, it was found that the present computation simulated well the complicate cavitating flow in inducer and gave a good estimation of inducer characteristics. At the inlet tip blade angle decreases, the occurrence of cavitation decreases in the cavitation regime, resulting in increasing the cavitation performance. Detailed observation and development of cavitation with respect to the cavitation number as well as the inlet blade angle are provided and discussed.

In the last decades, fluorites crystals (MeF2, Me = Ca, Ba, Sr, Pb) doped with trivalent rare-earth ions (RE3+) have attracted attention of research community due to their various applications such as: lasers, quantum electronics, scintilators or photosensors in PET (positron-emission-tomography) scanner. The goal of this work is to investigate the spectoscopic properties of gamma irradiated BaF2:CeF3 crystal. In order to investigate the quality of the as-grown crystal the dislocation density was estimated. The dislocation density is around 1.3×105 disloc./cm2. After irradiation with gamma rays, the absorption spectra reveal the appearance of a new absorption band in the 400-600nm region. The induced absorption bands depend on the gamma rays dose and the peaks intensities increase with the dose of radiation.In the last decades, fluorites crystals (MeF2, Me = Ca, Ba, Sr, Pb) doped with trivalent rare-earth ions (RE3+) have attracted attention of research community due to their various applications such as: lasers, quantum electronics, scintilators or photosensors in PET (positron-emission-tomography) scanner. The goal of this work is to investigate the spectoscopic properties of gamma irradiated BaF2:CeF3 crystal. In order to investigate the quality of the as-grown crystal the dislocation density was estimated. The dislocation density is around 1.3×105 disloc./cm2. After irradiation with gamma rays, the absorption spectra reveal the appearance of a new absorption band in the 400-600nm region. The induced absorption bands depend on the gamma rays dose and the peaks intensities increase with the dose of radiation.

The numerical analysis of thermal damage process proceeding in biological tissue, containing blood vessel, during laser irradiation is presented. Heat transfer in the tissue is assumed to be transient and two-dimensional with perfusion coefficient dependent on tissue injury. The internal heat source resulting from the laser irradiation based on the solution of diffusion equation is taken into account. At the stage of numerical computations the boundary element method and the finite difference method have been used. In the final part of the paper the results obtained are shown.

In this paper, couple stress fluid flow in a rectangular channel generated due to applied transverse magnetic field. Since the magnetic parameter is very small, the induced magnetic field is neglected. The 4th order PDE for axial velocity w is solved under i) the no slip and ii) hyper stick boundary conditions. The velocity w is obtained in Fourier series. The effects of physical parameters like couple stress parameter and Hartmann number on skin friction and volumetric flow rate are studied through graphs. It is observed that the external magnetic field decreases the skin friction and the volumetric flow rate.

In this paper, we investigate the linear and nonlinear (NL) optical properties of gold nanoparticles (Au-NPs) with different sizes. A colloidal gold nanoparticles solution has prepared to utilize the chemical reduction method by interacting gold chloride solution HAuCl4 with trisodium citrate solution. By using a hotplate and vigorous stirring the flask, which has the mixture solution, was heated to produce a 0.05 mg/ml of colloidal gold nanoparticles. The characterization of gold nanoparticles is executed by the utilization of different techniques. The information about nanoparticles size was achieved from the spectra measured by transmission electron microscopy (TEM). As well as the compositional characteristics are obtained using FTIR and XRD techniques. Finally, the Surface Plasmon Resonance (SPR) peaks were measured using a UV-Vis spectrophotometer. A Z-scan technique was utilized to study the nonlinear optical properties of Au nanoparticles. From the preparation of the nanoparticles, the shape of gold nanoparticles was almost spherical and has two different sizes. The nonlinear refractive index of Au nanoparticles was obtained in the order of 10-10 cm2/w extracted from a closed aperture z-scan. The nonlinear absorption of these nanoparticles was measured at 10−5 cm/w range obtained from an open aperture z-scan technique.

In the present study optical transmission spectra were recorded within the spectral range from 300 nm to 900 nm for pristine and 100 MeV Ag swift heavy ion irradiated amorphous Ge23Se62As15 thin films with mean coordination number 2.61 for six different fluences (3x1010 ions/cm2, 1x1011 ions/cm2, 3x1011 ions/cm2, 1x1012 ions/cm2, 3x1012 ions/cm2, and 1x1013 ions/cm2). The absorption coefficient calculated by using Lambert-Beer law. The optical band gap is calculated by Tauc's method, which based on absorption coefficient using non-direct transition for chalcogenide semiconductors. The static refractive index is calculated by using Dimitrov-Sakka theoretical model. Reduction in optical band gap and increment in linear refractive index till fluence 3x1012 ions/cm2 is understood using Raman measurement to utilize in optical applications.

In photoacoustic spectroscopic (PAS) technique, acoustic piston model is considered and the optical properties of solids are studied. One has to detect the photoacoustic (PA) signal produced when a sample placed in a cell is irradiated by an intensity modulated beam of light. The PA signal is used to investigate the optical properties of solids. In this paper we report on the theoretical, experimental issues on the application of photoacoustic spectroscopy for the investigation of optical properties of Cu2GeSe3 compound. Optical-absorption spectra has been obtained in the range of 0.76 -0.81 eV photon-energy at temperatures between 70 and 300 K. The thermal variation of band-gap energy has been estimated from the optical-absorption spectra at different temperatures.

2-amino-5-nitropyridiniumsulfamate, a nonlinear optical (NLO) single crystal was irradiated using Au3+ ion with various fluencies such as 1 x 1013 ions/cm2, 5 x 1013 ions/cm2 and 1 x 1014 ions/cm2. Quality of unirradiated and irradiated crystals was studied using single crystal X-ray diffraction. Functional group of irradiated and pristine crystal was measured confirmed using FTIR. Optical properties of irradiated and pristine samples were measured and from the absorption spectra, it was noticed that absorption increased with increase of ion fluence due to capture of existing ion vacancies and there was no additional peak observed. It was due to the energy transferred by SHI was not enough to move atoms from lattice to substitution position.

Lagrangian formulations of Hill's linear isotropic hyperelastic material models based on the one-parameter (r) ltskov family of strain tensors are developed. These formulations are based on the use of pairs of conjugate Lagrangian stress and strain tensors. Fourth-order elasticity tensors are obtained for these material models. The developed formulations of isotropic hypere- lastic material models are implemented into the commercial finite element MSC.Marc code. lt is shown that the Pelzer isotropic hyperelastic material model is competitive with the Mooney-Rivlin material model.

Vacancy type defect profiles of Al+ implanted Semi- Insulating (SI) 6H- SiC have been obtained using low energy positron beam Doppler broadening spectroscopy measurements. Al+ ions of 400 keV with fluence 1014, 1015 and 1016 ions/cm2 have been implanted at room temperature to produce donor concentration from 1018 to 1020 Al+/cm3. The increases in S – parameter vs. positron beam energy E indicates the production of vacancies type defects by implantation. The normalized S – parameter with pristine for implanted 6H- SiC samples confirms the production of di-vacancies (for 1014 and 1015 ions/cm2) and larger voids (for 1016 ions/cm2)..

In this work, we investigated the effects of 63 MeV proton irradiation on the electrical performance of long-wave infrared InAs/GaSb type-II superlattice barrier detectors. The dark current density increase due to displacement dose effects does not exceed a factor of 2.6, regardless of the absorber thickness, when measured after a proton fluence of 8×1011 H+/cm2 at 100 K. Subsequent analysis showed that the dark current changes behavior after irradiation, and the dominant current is no longer diffusion but generation–recombination and trap-assisted tunneling. Device simulation also allowed us to extract a minority carrier lifetime before and after irradiation, which decreases with increasing fluence as a result of the 63 MeV proton-induced mild material degradation.

In cardiovascular flows, Lagrangian coherent structures have been used to explore the skeleton of blood transport. Revealing these transport barriers is instrumental to quantify the mixing and stagnation of blood as well as to highlight locations of elevated strain rate on blood elements. Nevertheless, the clinical use of Lagrangian coherent structures in cardiovascular flows is rarely reported due largely to its non-intuitive nature and computational expense. Here, we explore a recently developed approach called “Lagrangian descriptors,” which quantifies the finite time Euclidean arc length of Lagrangian trajectories released from a grid of initial positions. Moreover, the finite time arc lengths of a set of trajectories capture signatures of Lagrangian coherent structures computed from the same initial condition. Remarkably, the Lagrangian descriptors approach has the most rapid computational performance among all its Lagrangian counterparts. In this work, we explore the application of Lagrangian descriptors for the first time in cardiovascular flows. For this purpose, we consider two in vitro flow models studied previously by our group: flow in an abdominal aortic aneurysm and that in a healthy left ventricle. In particular, we will demonstrate the ability of the Lagrangian descriptors approach to reveal Lagrangian coherent structures computed via the classical geometrical approach, though at a significantly reduced computational cost.

Determining synchronization, causality, and dynamical similarity in highly complex nonlinear systems like brains is challenging. Although distinct, these measures are related by the unknown deterministic structure of the underlying dynamical system. For two systems that are not independent on each other, either because they result from a common process or they are already synchronized, causality measures typically fail. Here, we introduce dynamical ergodicity to assess dynamical similarity between time series and then combine this new measure with cross-dynamical delay differential analysis to estimate causal interactions between time series. We first tested this approach on simulated data from coupled Rössler systems where ground truth was known. We then applied it to intracranial electroencephalographic data from patients with epilepsy and found distinct dynamical states that were highly predictive of epileptic seizures.

The hues of blue birds come from constructive interference, but scattering and refraction also matter.

The phenomena of intermittent and complete synchronization between two out of three identical, magnetically coupled SQUIDs (Superconducting QUantum Interference Devices) are investigated numerically. SQUIDs are highly nonlinear superconducting oscillators/devices that exhibit strong resonant and tunable response to applied magnetic field(s). Single SQUIDs and SQUID arrays are technologically important solid state devices, and they also serve as a testbed for exploring numerous complex dynamical phenomena. In SQUID oligomers, the dynamic complexity increases considerably with the number of SQUIDs. The SQUID trimer, considered here in a linear geometrical configuration using a realistic model with accesible control parameters, exhibits chaotic and hyperchaotic behavior in wide parameter regions. Complete chaos synchronization as well as intermittent chaos synchronization between two SQUIDs of the trimer is identified and characterized using the complete Lyapunov spectrum of the system and appropriate measures. The passage from complete to intermittent synchronization seems to be related to chaos-hyperchaos transitions as has been conjectured in the early days of chaos synchronization., Comment: 11 pages, 9 figures, submitted to Chaos, In memory of Vadim S. Anishchenko

A model on magnetic drug targeting is developed to determine the capture conditions on the efficient dispersion of drug-coated nanoparticles in a tumor environment. These particles consist of a non-magnetic core material containing embedded magnetic nanoparticles and a therapeutic agent (such as a photodynamic sensitizer). In the present problem, we have studied the solute dispersion during magnetic drug targeting through a microvessel. The particles are injected into the microvascular system upstream of the cancerous tissue and captured in the tumor using an applied magnetic field. The fluid velocity and the particle velocity due to the magnetic field are calculated analytically, while the solute transport equation is solved numerically by using the finite difference method. The fluid force is assumed on the capillary and the carrier undergoing magnetic force due to an external magnetic field. Solving the equations of fluid flow and solute transport simultaneously, the influence of the model biological parameters, such as volume fraction of the nanoparticles, magnetization, magnet–tumor distance, permeability of the capillaries, Peclet number, drug elimination, source term, and radius of the nanoparticle in the dispersion of drug-coated nanoparticles in microvessels, is also discussed. The results show that higher values of volume fraction of the magnetic particles, magnetization of the magnet, drug elimination, and source term associated with longer times are taken by drug-coated magnetic nanoparticles to reach the tumor position. Moreover, an increase in the tumor–magnet distance, permeability of the microvessel, Peclet number, and radius of the nanoparticle slows the rate at which the drug-coated magnetic nanoparticles reach the tumor position.

In microwave-induced thermo-acoustic tomography, the quality of reconstructed images is seriously influenced by the speed of sound distribution, which is usually set according to the speed of sound (SoS) of the background coupling medium or an empirical value. To reduce defocusing and distortions induced by acoustic inhomogeneity in microwave-induced thermo-acoustic tomography, a method is proposed. We classify the initial reconstructed pressure by the difference in dielectrics and update the acoustic property accordingly. A spare spectrum is obtained by the proposed method and partitions the initial pressure into several clusters, and then SoS will be updated based on clinical statistics with which the pressure is reconstructed again. The proposed method is first validated in the anatomically realistic breast phantom; an ex vivo experiment based on a prototype system is carried out for further validation. The results prove that the proposed method has a reliable effect on reducing distortions than the state-of-art methods under the condition of a low signal to noise ratio.