Values Of Field Intensity Research Articles

Application of the FDTD Method to the Analysis of Electromagnetic Wave Propagation in Systems with Concrete and Reinforced Concrete

Wireless communication very often causes problems due to its quality. Problems with the network are very important when installing wireless networks inside buildings. The reason is the effects created during the propagation of electromagnetic waves inside rooms due to, among other factors, the construction of the walls and the building materials used. At the stage of network design, it is possible to use numerical methods, which allow for multivariate and fast analysis. This article presents a multivariate analysis of the impact of the variability in the electrical parameters of concrete and reinforced concrete on the propagation of electromagnetic waves and the value of the electric field intensity. The subject of the analysis was a wall composed of a homogeneous material (concrete) or non-homogeneous material (concrete with reinforcement). In the case of the homogeneous wall, the analysis was performed taking into account four electric permittivity values and a wide range of conductivity values. The analysis was performed at two frequencies used in wireless communication (2.4 GHz and 5 GHz). The analysis was performed using the time method based on Maxwell’s equations—the finite difference time domain method (FDTD). The results of the numerical analysis were compared with the results obtained from the presented analytical relationships. In the next step, four models and calculations were obtained for systems with a reinforced concrete wall, taking into account the variability in the spacing between the bars, the diameter of the reinforcement and the number of rows of reinforcement. The analysis of complex systems was performed at a frequency of 2.4 GHz. The aim of the presented analysis was to check how the change in the value of the electric permittivity of concrete affects the values of the field intensity and its effect on the analysis of systems composed of concrete with reinforcement. In the case of concrete, it was observed that, for conductivity above 0.9 S/m, regardless of the electric permittivity, all characteristics had a similar course. For low concrete loss, the greatest differences in the electric field intensity were observed at a frequency of 2.4 GHz rather than at 5 GHz. On the other hand, the analysis of systems with reinforced concrete showed, among other aspects, that models with two rows of bars and spacing of 0.15 m, regardless of the reinforcement diameter, were characterized by lower values of the electric field intensity compared to the variants with one row of bars.

The Influence of Building Materials and Electrical Parameter Variability on Electromagnetic Wave Propagation

The article presents an analysis of the influence of building materials on the propagation of an electromagnetic wave and the values of the electric field intensity. The topics of the analysis were two types of walls (partition and load bearing) built of different building materials. Different variants of walls were considered due to the building material used: concrete, aerated concrete, solid brick, clinker bricks, and three types of hollow bricks. The requirements for structures in terms of wall thickness were taken into account. The article, using concrete as an example, also describes the influence of changes in the electrical parameters of the building material on wave propagation and the values of the field. The results concerning the influence of complex materials, such as hollow bricks, on the non-uniform distribution of the electric field were also included. Due to the different percentage share of ceramic mass in hollow bricks, the article discusses its influence on the values of the field, taking into account the variability of conductivity. The analysis was performed using the Finite Difference Time Domain (FDTD) method. The results were compared with the analytical solution. The analysis, among others, showed that with the increase in the ceramic mass in bricks, the electric field values are higher but result in an uneven distribution of the field. Using the example of hollow bricks used to build load-bearing walls, it was observed that a small modification of the hollows practically does not affect the field intensity (the difference is approx. 2%). When planning the installation of wireless networks, the best solution is walls made of ceramics with a large number of hollows, where the ceramic mass constitutes only approx. 30%. A multivariate analysis allows for a better understanding of field phenomena inside single-family homes.

Application of the FDTD Method for Multivariate Analysis of the Influence of Conductivity and the Arrangement of Hollows Inside Bricks on the Values of Electric Field Intensity

The article contains a numerical analysis of the effects of electromagnetic wave propagation in an area containing a non-ideal, non-uniform, and absorbing dielectric. The analysis concerned the influence of the structure of the building material and its electrical parameters on the electric field intensity. The analysis took into account the variability of the number of hollows in the brick, the width of hollows, as well as the arrangement of these hollows relative to each other using the example of two types of bricks. The article also provides the most commonly used values of electrical parameters for building materials (brick, plaster). For this reason, the article includes results for different values of conductivity (0–0.2 S/m). The FDTD (Finite Difference Time Domain) method was used for multivariate analysis. The aim was to verify the correctness of the numerical assumptions adopted. Using the example of the most commonly used wall structure in construction, the results obtained using the FDTD method were compared with values obtained using another numerical method, the finite element method (FEM). The influence of an additional layer of plaster on the considered wall on the electric field was also checked. The analysis showed that a symmetrical arrangement of bricks results in higher values of the electric field by an average of 20%. Of course, this depends on the length of the hollows and the number of holes. The highest field values occur at low conductivities (0–0.04 S/m). A brick wall with a larger number of hollows and a symmetrical brick arrangement shows the highest electric field intensity, especially for hollow sizes (0.009–0.015 m).

Application of the FDTD Method to Analyze the Influence of Brick Complexity on Electromagnetic Wave Propagation

This article presents a numerical analysis of the effects related to the propagation of electromagnetic waves in an area containing a non-ideal, non-uniform, and absorbing dielectric. The analysis concerns the influence of electrical parameters, the structure of the building material, and the layering of the wall on the values of the electric field intensity. A multivariate analysis was carried out with different conductivity values. Homogeneous materials (e.g., solid brick) can be analyzed using the analytical method. In the case of complex materials containing, e.g., hollows (brick with hollows, hollow block), it is necessary to use the numerical method. The FDTD (finite difference time domain) method was used to assess the dependence of the electric field intensity on the layering, the length of hollows in bricks, and the material loss. In order to check the correctness of the adopted numerical assumptions, a series of tests related to the discretization of the model was carried out. The article also presents the influence of changing the length of hollows in bricks on the values of the electric field intensity at a frequency of 2.4 GHz. The instantaneous field distributions and maximum values of the electric field intensity are presented. In the model with a two-layer wall, regardless of the conductivity, the field values were the same for the two models, where the difference in the percentage of ceramic mass in the brick was 8%. A 12% decrease in the percentage of ceramic mass in the brick resulted in a 15% increase in the value of the area between a single-layer and a double-layer wall made of clinker bricks. At a conductivity of 0.04 S/m for a single-layer wall, the field values were similar for all brick variants.

Abstract A008: The effect of body mass index on Tumor Treating Fields (TTFields) intensity distribution in the abdomen: results of a simulation model study

Abstract Introduction: Tumor Treating Fields (TTFields) are electric fields that disrupt processes critical for cancer cell viability and tumor progression. They are generated by a portable medical device and delivered noninvasively to the tumor site via skin-placed arrays. TTFields therapy is approved for the treatment of recurrent and newly diagnosed glioblastoma as well as pleural mesothelioma. Recently, the randomized, pivotal (phase 3) LUNAR study (NCT02973789) demonstrated improved overall survival for TTFields therapy (150 kHz) delivered continuously until progression or intolerable toxicity together with an immune checkpoint inhibitor (ICI) or docetaxel (DTX) vs ICI/DTX alone in patients with metastatic non-small cell lung cancer following progression on or after platinum-based therapy. PANOVA-3 (NCT03377491) is an ongoing pivotal (phase 3), randomized, open-label study evaluating the safety and efficacy of TTFields therapy (150 kHz) together with nab-paclitaxel and gemcitabine for the treatment of patients with unresectable, locally advanced pancreatic adenocarcinoma. The effects of TTFields are dependent on several factors (i.e., intensity, frequency, and distribution) which may be affected by tissue composition/conductivity and array layout. Here, we evaluate guideline TTFields array layouts for TTFields delivery to the abdominal region at therapeutic intensities (∼1 V/cm [amplitude]) using simulation models with varying body mass index (BMI). Methods: Computerized phantom models (Ella, females with BMIs of 22, 26 and 30 kg/m2) were used to simulate the distribution of TTFields. Two different arrays sizes (small [13 disks] and large [20 disks]) were applied to the abdominal region of the models based on abdominal TTFields array layout guidelines. Region of interest (ROIs) included the left and right hypochondriac, left and right lumbar, epigastric, and umbilical regions. Simulations were performed using the Sim4Life platform v6.2.1.4910 (Zurich MedTech, Zurich, Switzerland). Electric field intensity distribution maps were generated for each model, and electric field intensity values across all ROIs in the abdomen were analyzed. Results: Electric field intensities were generally lower in the higher BMI model compared with the lower BMI models (field intensities across all ROIs were 1.60–2.57 V/cm for the 22 kg/m2 BMI model, 1.36–2.13 V/cm in the 26 kg/m2 BMI model and 1.35–1.97 V/cm in the 30 kg/m2 BMI model). However, all BMI models achieved TTFields intensities at therapeutic levels (∼1 V/cm) in all ROIs. Conclusions: Results from this simulation-based study demonstrate the feasibility of delivering TTFields at therapeutic intensities to patients with abdominal tumors regardless of their BMI when using abdominal guideline layouts. Citation Format: Ariel Naveh, Nadav Shapira. The effect of body mass index on Tumor Treating Fields (TTFields) intensity distribution in the abdomen: results of a simulation model study [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A008.

Comprehensive Analysis of Magnetic Flux Density and RF-EMF Exposure in Electric Buses: A Case Study from Samsun, Turkey.

This study investigates magnetic flux density (B) and radiofrequency electromagnetic field (RF-EMF) measurements on electric buses operating in Samsun, Turkey, focusing on two bus routes (called E1 and E4) during the morning and evening hours. Measurements were taken under diverse operational conditions, including acceleration, cruising, and braking, at locations of peak passenger density. Along the E1 route, the magnetic field intensity varied significantly based on the bus position, road slope, and passenger load, with notable increases during braking. In contrast, the E4 route showed a lower magnetic field intensity and RF-EMF values due to its straighter trajectory and reduced operational stops. The highest RF-EMF measurement recorded was 6.01 V/m, which is below the maximum levels established by the ICNIRP guidelines. In 11 out of the 12 different band-selective RF-EMF measurements, the highest contribution came from the downlink band of the base stations, while in only one measurement, the highest contribution originated from the uplink bands of the base stations. All data were subject to the Anderson-Darling test, confirming the generalized extreme value distribution as the best fit for both B and RF-EMF measurements. Additionally, the study assessed B levels inside and outside the bus during charging, revealing heightened readings near the pantograph. These findings significantly contribute to our understanding of electromagnetic field exposure in electric bus environments, highlighting potential health implications and informing the development of targeted mitigation strategies.

Effect of dielectric material on the uniformity of nanosecond pulsed dielectric barrier discharge

Dielectric barrier discharge (DBD) is considered as a promising technique to produce large volume uniform plasma at atmospheric pressure, and the dielectric barrier layer between the electrodes plays a key role in the DBD processes and enhancing discharge uniformity. In this work, the uniformity and discharge characteristics of the nanosecond (ns) pulsed DBD with dielectric barrier layers made of alumina, quartz glass, polycarbonate (PC), and polypropylene (PP) are investigated via discharge image observation, voltage-current waveform measurement and optical emission spectral diagnosis. Through analyzing discharge image by gray value standard deviation method, the discharge uniformity is quantitatively calculated. The effects of the space electric field intensity, the electron density (N e), and the space reactive species on the uniformity are studied with quantifying the gap voltage U g and the discharge current I g, analyzing the recorded optical emission spectra, and simulating the temporal distribution of N e with a one-dimensional fluid model. It is found that as the relative permittivity of the dielectric materials increases, the space electric field intensity is enhanced, which results in a higher N e and electron temperature (T e). Therefore, an appropriate value of space electric field intensity can promote electron avalanches, resulting in uniform and stable plasma by the merging of electron avalanches. However, an excessive value of space electric field intensity leads to the aggregation of space charges and the distortion of the space electric field, which reduce the discharge uniformity. The surface roughness and the surface charge decay are measured to explain the influences of the surface properties and the second electron emission on the discharge uniformity. The results in this work give a comprehensive understanding of the effect of the dielectric materials on the DBD uniformity, and contribute to the selection of dielectric materials for DBD reactor and the realization of atmospheric pressure uniform, stable, and reactive plasma sources.

Schwinger correlation of Dirac fields in accelerated frames

We study the Schwinger correlation of Dirac fields in the noninertial frames under the influences of both constant and pulsed electric fields. We use both the entanglement negativity and quantum mutual information between particle and antiparticle as the indicator of the Schwinger correlation observed by the accelerated observers. We find that the Schwinger correlation in the inertial frames is the largest. With the increase of acceleration of the observers, the Schwinger correlation becomes smaller and smaller, but does not vanish in the limit of infinite acceleration. For the given acceleration, the Schwinger correlation is a nonmonotonic function of the electric field intensity, and there is an optimal value of electric field intensity for which the Schwinger correlation is the largest. In the case of pulsed electric fields, the Schwinger correlation is also the nonmonotonic function of pulsed width, which suggests the existence of optimal pulsed width for observing Schwinger correlation.

Three-Dimensional Transient Electric Field Characteristics of High Pressure Electrode Boilers

An uneven electric field during the operation of an electrode boiler will lead to the emergence of a high field strength area and low field strength area in the furnace, which will endanger the safe and reliable operation and heating efficiency of the electrode boiler. A numerical study of three-dimensional transient electric field distribution characteristics in a 10 kV high-voltage electrode boiler was carried out. The distribution characteristics of the global electric field of the electrode boiler under the nominal voltage of 10 kV were studied, and the distribution law of the electric field of the electrode boiler under poor power quality, such as different bus voltage and three-phase voltage imbalance, was explored. The results show that the electric field distribution characteristics of the three-phase transient are more obvious in the section closer to the electrode disc, and the electric field distribution is the most uniform in the section that is 1.4 m away from the furnace water. In the case of poor power quality, such as different bus voltage and three-phase voltage imbalance, the points of the maximum electric field intensity of the four surfaces change periodically with time, and the greater the bus voltage fluctuation, the more severe the impact on the transient electric field. The three-phase voltage imbalance will shift the peak value of the electric field intensity. The decrease or offset of electric field intensity in the electrode boiler caused by poor power quality will directly affect its heating efficiency. The electric field simulation results have a specific reference value for improving the internal electric field distribution and on-site operation and maintenance of the electrode boiler.

Internal dynamics of a polaron uniformly moving along a molecular chain in a constant electric field

This paper presents a detailed study of the uniform motion of a Holstein polaron as it moves along a chain in a constant electric field. The calculations showed that, depending on the parameters of the system, the duration of the uniform motion of the polaron along the chain can reach tens and hundreds of Bloch periods for a given value of the electric field intensity. It is shown that in the process of the uniform motion, the macro-part of the polaron moves at a constant velocity, retaining its shape. At the same time, the low-density components of the polaron, which arise immediately when a constant electric field is instantaneously switched on, have their own internal dynamics and demonstrate characteristic elements of the Bloch oscillations, such as the period of Bloch oscillations and the maximum Bloch amplitude. It is shown that not only the velocity and duration of the uniform motion of the polaron, but also the characteristics of the low-density components of the polaron depend on the value of the electric field intensity.

Design and characterisation of a cell exposure system with high magnetic field homogeneity: RILZ coils.

In vitro studies requiring controlled exposure to low-frequency electromagnetic fields employ exposure systems with different geometries and configurations, the Helmholtz configuration being one of the most widely used. This configuration has limitations in the homogeneity of the spatial distribution of the magnetic field intensity values. We present the design, manufacturing, and characterisation of a new coil system, called RILZ configuration, which improves the distribution of magnetic field intensity values in the three dimensions of space for three different heights in comparison with the traditional circular coils in Helmholtz configuration. In addition, a comparative study of the cellular response in CT2A cultures exposed to a magnetic field of 50 Hz and 100µT for 48hrs is performed with both exposure systems. The results of the study show reduced values of deviation from the central value of magnetic field intensity using the RILZ coil system. These differences are statistically significant compared to the Helmholtz configuration for the three Cartesian directions: x (p < 0.01), y (p < 0.01), z (p < 0.01). In addition, the intensity values for three different heights are statistically significantly correlated using the RILZ coil system (p < 0.01). The differences in cell behaviour are also statistically significant between the two systems (p < 0.01) and may be directly related to the differences found in the distribution of intensity values between the two systems. This study highlights the importance of the homogeneity of the magnetic field intensity generated by the exposure systems used and offers an effective solution to control the magnetic field exposure parameters in vitro assays.

Study on electromagnetic dosimetry of the power cable in electric vehicle

To calculate the induced fields in the human body of the driver in an electric vehicle, the power cables of the electric vehicle are taken as the electromagnetic exposure source. The finite elements method is used to construct the electromagnetic environment model, which consists of the vehicle body, the power cables, and the driver body. The maximal values of the magnetic flux density inside the driver’s trunk and head are 4.63 μT and 0.12 μT, respectively. The maximal induced electric field intensity values are 670 mV/m and 99.7 mV/m, respectively. All values are below the safety limits of the ICNIRP. The results show that the electromagnetic environment induced by the power cables is safe for the driver. The study could provide a reference for improving electromagnetic exposure standards for electric vehicles.

Transition from a Uniform Mode of Polaron Motion to an Oscillatory One When the Initial Polaron State Changes

A study of the nature of the motion of a Holstein polaron in a homogeneous polynucleotide chain in a constant electric field, depending on the initial polaron state, was carried out. The calculations performed showed that the duration of the uniform motion of the polaron along the chain is finite and depends on the entire set of system parameters, including the characteristic size of the initial polaron state. It is shown that at a fixed value of the electric field intensity, an increase in the characteristic size of the initial polaron state leads to a decrease in the time of uniform motion of the polaron along the chain. The calculations carried out earlier showed that with the uniform movement of the polaron along the chain, low-density components of the polaron are formed immediately after the electric field is turned on. Moreover, the low-density components of the polaron have their own internal dynamics, which are different from the dynamics of the macro-part of the polaron. With uniform motion, the macro-part of the polaron moves at a constant velocity, maintaining its shape, while the low-density components of the polaron demonstrate such characteristics of Bloch oscillations as the period of Bloch oscillations and the maximum Bloch amplitude. It is also shown that a change in the shape of the initial polaron state exerts influence upon not only the duration of the uniform motion of the polaron along the chain, but also the characteristics of the low-density components of the polaron.

Fabrication of a three-dimensional micro/nanocarbon structure with sub-10 nm carbon fiber arrays based on the nanoforming and pyrolysis of polyacrylonitrile-based jet fibers

To produce a three-dimensional micro/nanocarbon structure, a manufacturing design technique for sub-10 nm carbon fiber arrays on three-dimensional carbon micropillars has been developed; the method involves initiating electrostatic jetting, forming submicron-to-nanoscale PAN-based fibers, and maximizing the shrinkage from polyacrylonitrile (PAN)-based fibers to carbon fibers. Nanoforming and nanodepositing methods for polyacrylonitrile-based jet fibers as precursors of carbon fibers are proposed for the processing design of electrostatic jet initiation and for the forming design of submicron-to-nanoscale PAN-based fibers by establishing and analyzing mathematical models that include the diameter and tensile stress values of jet fibers and the electric field intensity values on the surfaces of carbon micropillars. In accordance with these methods, an array of jet fibers with diameters of ~80 nm is experimentally formed based on the thinning of the electrospinning fluid on top of a dispensing needle, the poking of drum into an electrospinning droplet, and the controlling of the needle–drum distance. When converting thin PAN-based jet fibers to carbon fibers, a pyrolysis method consisting of the suspension of jet nanofibers between carbon micropillars, the bond between the fibers and the surface of the carbon micropillar, and the control of micropillar spacing, stabilization temperature, and carbonation rate is presented to maximize the shrinkage from PAN-based fibers to carbon fibers and to form sub-10 nm carbon fiber arrays between three-dimensional carbon micropillars. The manufacturing design of a three-dimensional micro/nanocarbon structure can produce thin PAN-based jet nanofibers and nanofiber arrays aligned on micropillar surfaces, obtain shrinkage levels reaching 96% and incorporate sub-10 nm carbon fibers into three-dimensional carbon micropillars; these actions provide new research opportunities for correlated three-dimensional micro/nanocarbon structures that have not previously been technically possible.

The Effect of Body Mass Index on Tumor Treating Fields (TTFields) Intensity Distribution in the Lungs

Tumor Treating Fields (TTFields) therapy is a locoregional, noninvasive antimitotic cancer treatment modality. TTFields are electric fields that disrupt processes critical for cancer cell viability and tumor progression. They are generated by a portable medical device and delivered noninvasively to the tumor via two pairs of orthogonally placed transducer arrays. TTFields therapy is currently FDA-approved for recurrent and newly diagnosed glioblastoma and pleural mesothelioma, with ongoing studies in other solid tumor types including non-small cell lung cancer (NSCLC). In the phase 3 LUNAR study (NCT02973789), TTFields therapy demonstrated an improvement in overall survival when added to NSCLC standard of care. TTFields effectiveness depends upon several factors, including field intensity; thus, it is relevant to assess the impact of body mass index (BMI) on the distribution of TTFields in the lungs. This study utilized simulation-based approaches to assess the impact of BMI on electric field intensity distribution in the lungs. Three computerized female phantom models (with BMIs of 22, 26 and 30), were used to simulate electric field intensity. Two different arrays sizes (small [13 disks] and large [20 disks]) were applied to the thoracic region of the models. An electric field intensity distribution map for each model was generated, and electric field intensity values across the entirety of the lungs were analyzed. Electric field intensities were above 1 V/cm (amplitude), which is typically considered a sufficient level of TTFields dose to achieve a therapeutic effect, in all lobes in the lungs for all BMI models when large arrays were used. Therapeutic intensities were achieved in all lobes with the small arrays in all but one model (BMI 30), where intensities fell slightly below 1 V/cm in the right middle lobe. Results from this simulation-based study demonstrate that delivery of TTFields at therapeutic intensities is feasible even in patients with a high BMI, provided the appropriately sized array is used. These findings support ongoing clinical studies of TTFields therapy in lung cancer, including the recently completed LUNAR study in advanced NSCLC, and could facilitate optimization of therapeutic TTFields delivery to individual patients, based on their BMI.

Electric field and SAR distribution in the vicinity of dental implants exposed to the cell phone electromagnetic radiation

PurposeThe purpose of this paper is to determine the electric field and specific absorption rate (SAR) distribution within biological tissues in the vicinity of dental implants, exposed to the mobile phone radiation.Design/methodology/approachThis research was performed for the frequency of 2.6 GHz, which corresponds to 4G mobile network. The adequate 3D realistic numerical models of the mobile phone user’s head, dental implants and actual smartphone model are created using packages based on the finite integral technique numerical method.FindingsThe obtained results yield to a conclusion that the presence of dental implants affects the increase in electric field intensity and SAR values within biological tissues in its vicinity.Research limitations/implicationsThe presented procedure is limited to the 4G mobile network frequency of 2.6 MHz. The study should be extended to other mobile network frequencies to be more general.Practical implicationsThe criteria for selection of the materials used for dental implants production should be extended with the recommended material characteristics related to their influence on the electric field and SAR distribution, to keep their values in the limits prescribed by standards.Social implicationsThe obtained results provide the foundation for future research in mobile devices’ electromagnetic fields’ influence on human health.Originality/valueThe accurate determination of the electric field and SAR values within different biological tissues and organs in the vicinity of dental implants exposed to mobile phone electromagnetic radiation, demands highly realistic model of observed biological structures. For purposes of the current study, the procedure for modeling of highly nonhomogeneous structure with finite number of homogenous domains having known electromagnetic parameters is described in the paper. As a result, the 3D complex users’ head model formed of 16 homogeneous domains of different electromagnetic parameters is created.

Harmonic Analysis of the Polarization Reversal of the Rb2ZnCl4 Crystal in the Incommensurate Phase

The polarization reversal of Rb2ZnCl4 crystals in the incommensurate phase near a ferroelectric phase transition (PT) under the action of harmonic electric field has been studied using harmonic analysis. During polarization reversal of a test sample under the action of harmonic electric field, a PT induced by the electric field from the incommensurate phase to the ferroelectric phase and a PT from the field-induced ferroelectric phase back to the incommensurate phase occur. The study of the active and reactive contributions to the amplitudes of current density harmonics made it possible to determine the current values of harmonic electric field intensity at which the corresponding PTs occur.

Natural convection and entropy generation in a trapezoidal region with hybrid nanoliquid under magnetic field

PurposeThis paper aims to study numerically the steady natural convective heat transfer of a hybrid nanosuspension (Ag-MgO/H2O) within a partially heated/cooled trapezoidal region with linear temperature profiles at inclined walls under an effect of uniform Lorentz force. This investigation is useful for researchers studying in the area of cavity flows to know features of the flow structures and nature of hybrid nanofluid characteristics. In addition, a detailed entropy generation analysis has been performed to highlight possible regimes with minimal entropy generation rates.Design/methodology/approachThe governing equations formulated using the Oberbeck–Boussinesq approach and single-phase nanoliquid model are transformed to a non-dimensional form by using non-dimensional variables. The obtained equations with appropriate boundary conditions are resolved by the finite difference technique. The developed code has been validated comprehensively. Analysis has been performed for a wide range of governing parameters, including Rayleigh number (Ra = 105), Prandtl number (Pr = 6.82), Hartmann number (Ha = 0–100), magnetic field inclination angle (φ = 0–?/2) and nanoparticles volume fraction (φhnf = 0 and 2%).FindingsIt has been shown that inclined magnetic field can be used to manage the energy transport performance. An inclusion of nanoparticles without Lorentz force influence allows forming more stable convective regime with descending heat plume in the central zone, while such a regime was performed for clear fluid only for moderate and high Hartmann numbers. Moreover, the average overall entropy generation can be decreased with a growth of the Hartmann number, while an addition of hybrid nanoparticles allows reducing this parameter for Ha = 30 and 50. The average Nusselt number can be increased with a growth of the nanoparticles concentration for low values of the magnetic field intensity.Originality/valueGoverning equations written using the conservation laws and dimensionless non-primitive variables have been resolved by the finite difference approach. The created numerical code has been verified by applying the grid independence test and computational outcomes of other researchers. The comprehensive analysis for various key parameters has been performed.

The association between body mass index and distribution intensity of tumor treating fields (TTFields) in the lungs.

e20559 Background: Tumor Treating Fields (TTFields) therapy is a first-in-class locoregional and noninvasive cancer treatment modality. TTFields are electric fields that disrupt processes necessary for cancer cell viability and tumor progression. A portable medical device generates TTFields, which are delivered noninvasively to the tumor area via 2 pairs of transducer arrays placed on the skin. TTFields therapy is currently approved for recurrent and newly diagnosed glioblastoma and pleural mesothelioma, with studies underway in other solid tumor types, including non-small cell lung cancer (NSCLC). Preclinical studies have shown that the effectiveness of TTFields depends on several factors, including field intensity. Given that 1 in 3 adults is overweight or obese, it is relevant to determine the effect of body mass index (BMI) on TTFields intensity to the lungs. Simulation-based methods were utilized, with the hypothesis that TTFields could be delivered to regions of interest (ROI) at therapeutic field intensities of &gt; 1 V/cm, irrespective of BMI. Methods: Female computer phantom models with BMIs of 22 (healthy), 26 (overweight), and 30 (obese) were used to simulate TTFields intensity using small (13 disk) and large (20 disk) arrays placed on the thoracic region. The distribution of TTFields in each model was then determined using a computer-generated electric field intensity map. Field intensity values across the entire lungs were analyzed and compared. Results: When TTFields were delivered with large arrays, field intensities were clinically meaningful ( &gt; 1 V/cm) in all lobes of the lungs for all BMI models. When TTFields were delivered with small arrays, meaningful levels of field intensity were achieved in all lung lobes, except for the BMI 30 model, where field intensities were slightly lower than 1 V/cm in the right middle lobe. Conclusions: These results show that TTFields can be delivered at therapeutic field intensities in patients with a BMI up to 30, providing the appropriate TTFields array size is used. Results from this simulation-based study support current clinical studies of TTFields therapy in lung cancer, (LUNAR, NCT02973789) and underscore the importance of appropriate array size selection. Additionally, these results may provide guidance for using TTFields therapy to treat a broad population of patients with lung tumors.

The vibration of a nanobeam subjected to constant magnetic field and ramp-type heat under non-Fourier heat conduction law based on the Lord-Shulman model

In this work, the usual Euler–Bernoulli nanobeam has been modeled in the context of the Lord-Shulman thermoelastic theorem which contains the non-Fourier heat conduction law. The nanobeam has been subjected to a constant magnetic field and ramp-type thermal loading. The Laplace transform definition has been applied to the governing equations and the solutions have been obtained by using a direct approach. The inversions of the Laplace transform have been calculated numerically by using the Tzou approximation method. The solutions have been applied to a nanobeam made of silicon nitride. The distributions of the temperature increment, lateral deflection, strain, stress, and strain-energy density have been represented in figures with different values of the magnetic field intensity and ramp-time heat parameter. The value of the magnetic field intensity and ramp-time heat parameter have significant effects on all the studied functions, and they could be used as tuners to control the energy which has been generated through the nanobeam.