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Most studies suggest that dose-specific radiation regimens are essential for optimal induction of cancer cell response. This study focused on determining β-radiation-absorbed dose (rad) effects on the cell viability, cytotoxicity, hypersensitivity, and cell death of K562 cells using experimental methods and Monte Carlo simulation (MCS).The K562 cells were cultured and irradiated with β-particles emitted from a strontium source in vitro, with the estimated daily activity of 1.238 μCi. The treated cells were radiated at least three times every day for 3 consecutive days. The cell viability and apoptosis were investigated in treated cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, DNA electrophoresis, Hoechst dye, and inverted microscope. The average absorbed doses were obtained by MCS (MCNPX code). To verify simulation and experimental results, we used a Geiger-Muller counter and estimated a scaling factor.The cytotoxic effects and cell death were induced in the treated groups via rad in a time-dependent manner. The highest apoptotic and cytotoxic effects were observed in cells after irradiation with β-particles for 120 min per day in 3 consecutive days. rads were determined using MCNPX code and cell survival rates were significantly reduced during irradiation periods. No significant hyper-radiosensitivity was found based on experimental and theoretical results.Despite the difficult calculation of the rad in the target cells and the scant information in this field, fortunately we have achieved significant theoretical data consistent with the experimental results. Our findings also introduced MCS as a better choice for evaluating of rad effects under different cellular conditions with high accuracy.

In this study, the free vibration of a composite sandwich plate reinforced with graphene nanoplatelets (GPLs) enclosed by piezoelectric layers is investigated using an analytical solution. In the framework of the first-order shear deformation plate theory, multilayer functionally graded graphene platelets-reinforced composite plate is assumed. Applying modified Halpin–Tsai model and rule of mixtures, the effective Young’s modulus, mass density and Poisson’s ratio of nanocomposites are predicted. In each individual layer, the weight fraction of GPL nanofillers illustrates a layer-wise variation along the thickness direction either uniformly or non-uniformly GPLs dispersed. Based on Maxwell’s equation, the electric potential in a piezoelectric layer is considered for open and closed circuit boundary conditions. Coupled governing equations of motion and boundary conditions are derived by using the Hamilton’s principle. Four auxiliary scalar functions are introduced to decouple the governing equations of motion and boundary conditions, which are solved analytically by employing Levy-type boundary conditions. The effects of GPLs weight fraction, GPLs distribution patterns, number of layers and aspect ratio are examined in detail. The results show that the best way to predict the most effective reinforcement is to distribute more GPLs with a larger surface area near the top and bottom surfaces of the plate. Besides, adding a small amount of GPLs as reinforcing nanofillers can significantly improve the stiffness of the plate.

Because of their low cost, low energy consumption, high performance, and exceptional electrical properties, nanocomposites containing carbon nanotubes are suitable for use in many applications such as sensing systems. In this research work, a metal–semiconductor–metal (MSM) structure based on a multiwall carbon nanotube/high-density polyethylene (MWCNT/HDPE) nanocomposite is introduced as a neutron sensor. Scanning electron microscopy, Fourier-transform infrared, and infrared spectroscopy techniques were used to characterize the morphology and structure of the fabricated device. Current–voltage (I–V) characteristic modeling showed that the device can be assumed to be a reversed-biased Schottky diode, if the voltage is high enough. To estimate the depletion layer length of the Schottky contact, impedance spectroscopy was employed. Therefore, the real and imaginary parts of the impedance of the MSM system were used to obtain electrical parameters such as the carrier mobility and dielectric constant. Experimental observations of the MSM structure under irradiation from an americium–beryllium (Am–Be) neutron source showed that the current level in the device decreased significantly. Subsequently, current pulses appeared in situ I–V and current–time (I–t) curve measurements when increasing voltage was applied to the MSM system. The experimentally determined depletion region length as well as the space-charge-limited current mechanism for carrier transport were compared with the range for protons calculated using Monte Carlo n-particle extended (MCNPX) code, yielding the maximum energy of recoiled protons detectable by the device.

In this paper, a nonlinear Timoshenko beam model is considered to analytically investigate post-buckling and nonlinear vibration of flexible fluid-conveying pipes made of functionally graded materials. Closed-form expressions are presented to study the effects of shear deformation and rotary inertia on the post-buckling behavior and nonlinear vibration of fluid-conveying functionally graded pipes for the first time. It is assumed that the material property of the functionally graded material pipe is changed continuously along the direction of the pipe wall thickness based on a simple power law. Considering the Von-Karman nonlinear strain components and using the Hamilton's principle, the nonlinear governing equations for vibration and buckling of the functionally graded pipe conveying fluid are derived. These nonlinear governing equations are discretized by applying the Galerkin's procedure. The homotopy analysis method is employed to determine the closed-form expressions for the nonlinear frequency and the time history of vibration of the functionally graded pipe. The influences of rotary inertia and shear deformation on the buckling behavior, critical fluid velocity, nonlinear frequency and non-dimensional amplitude of the system are investigated and discussed in detail. The effects of physical parameters of the pipe conveying fluid on the divergence fluid velocity are studied by considering polypropylene random and functionally graded polymer pipes. The numerical results attest to the importance of considering rotary inertia and shear deformation in analyzing of short functionally graded material pipes especially for stiffer materials with higher initial amplitudes.

In many research fields and industry such as nuclear physics, notably nuclear technology, fusion plasma diagnostics, radiotherapy and radiation protection, it is very substantial that measure fast neutron spectra. For example in nuclear reactor primary generated neutrons have energies around 2 MeV that lie fast neutron category. Also particle accelerators and Am-Be neutron source raise fast neutrons. Therefore a review of silicon based fast neutron detection with proton recoil methods is surveyed. Furthermore Carbon nanoparticles (CNPs) with simple and low cost preparation methods with exceptional electrical properties have been used widely in nanoelectronic applications such as radiation sensors. In this chapter, fast neutron detectors using Carbon based semiconductor, back-to-back Schottky diode type, and polyethylene as convertor are developed and the Am-Be fast neutron source is used in experimental measurements.

This work is concerned with the low cost fabrication of carbon nanoparticles (CNPs), and its application to beta ray detection. The structural and morphological properties of the CNPs were obtained by spectral and microscopy techniques. A system based on CNPs application in the metal-semiconductor-metal (MSM) junction platform, which acts as a beta-ray (β-ray) sensor, is fabricated. The prototype is characterised by modelling, Monte Carlo simulation, and electrical investigations. Changes to the electrical behaviour of the proposed MSM system due to β-ray irradiation are validated by experimental results in both Ohmic and non-Ohmic (Schottky) contacts. The simulation was performed using the MCNPX code, which showed that most of the β-ray energies are deposited into CNPs and electrodes. However, in the Ohmic contact, because the β-ray is induced, the current of CNPs is decreased. The reduction of the current might be due to the change of the carrier properties by increasing the scattering of electrons. The current-density equation for electrons was employed for understanding the effects of β-ray in Ohmic contact of CNPs. On the contrary, in the Schottky contact case, CNPs current was increased with constant voltage when biased by β-ray irradiation. In this paper, the electron–hole generation using β-rays is dominant when compared to other significant effects of radiation exposure on semiconducting CNP-based Schottky contact. Hence, the current increment of CNPs can be justified by electron–hole generation in the depletion region.