Pressure induced evolution of superconductivity and magnetic hourglass dispersion in Fe1.02Te0.7Se0.3

Iron based high temperature superconductors have several common features with superconducting cuprates, including the square lattice and the proximity to an antiferromagnetic phase. The magnetic excitation spectrumbelowTc of Fe1.02Te0.7Se0.3 shows an hourglass-shaped dispersion with a resonance around the commensurate point . In a previous inelastic neutron scattering study, we showed that the hourglass-shaped dispersion is most likely a prerequisite for superconductivity, while the consequences are the opening of a gap and a shift of spectral weight. In this paper we follow the evolution of the hourglass shaped dispersion under applied pressure up to 12 kbar. Our results show that that the pressure-induced 37% increase of Tc is concomitant with a change in the magnetic excitation spectrum, with an increase of the hourglass energy by 38%

Pressure induced evolution of superconductivity and magnetic hourglass dispersion in Fe1.02Te0.7Se0.3

Iron based high temperature superconductors have several common features with superconducting cuprates, including the square lattice and the proximity to an antiferromagnetic phase. The magnetic excitation spectrum below T-c of Fe1.02Te0.7Se0.3 shows an hourglass-shaped dispersion with a resonance around the commensurate point. In a previous inelastic neutron scattering study, we showed that the hourglass-shaped dispersion is most likely a prerequisite for superconductivity, while the consequences are the opening of a gap and a shift of spectral weight. In this paper we follow the evolution of the hourglass shaped dispersion under applied pressure up to 12 kbar. Our results show that that the pressure-induced 37% increase of T-c is concomitant with a change in the magnetic excitation spectrum, with an increase of the hourglass energy by 38%

Effect of particle size, coupling agent and DDGS additions on Paulownia wood polypropylene composites

Studies aimed at improving the tensile, flexural, impact, thermal, and physical characteristics of wood–plastic composites composed of Paulownia wood flour derived from 36-month-old trees blended with polypropylene were conducted. Composites of 25% and 40% w/w of Paulownia wood were produced by twin-screw compounding and injection molding. Composites containing 0–10% by weight of maleated polypropylene were evaluated and an optimum maleated polypropylene concentration determined, i.e., 5%. The particle size distribution of Paulownia wood filler is shown to have an effect on the tensile and flexural properties of the composites. Novel combination composites of dried distiller’s grain with solubles mixed with Paulownia wood (up to 40% w/w) were produced and their properties evaluated. Depending on the composite tested, soaking composites for 872 h alters mechanical properties and causes weight gain

Effect of Uniform and Non-uniform High-z Nanoparticles Distribution in Tumor Volume on Dose Enhancement Factor During 192Ir Brachytherapy

Introduction: Irradiation of loaded tumor with high-Z nanoparticles with low energy photon of 192Ir source during brachytherapy increases absorbed dose of tumor due to increase in possibility of photoelectric phenomena. Therefore, this study aimed to investigate dose enhancement due to nanoparticles (NPs) with different atomic numbers and concentrations as well as effect of NPs distribution (uniform & non- uniform) on dose enhancement. Methods: Dosimetric parameters of HDR-192Ir source (MicroSelectron model) were calculated by MCNP-4C code on the basis of recommendations of AAPM, TG-43. A tumor (1 cm3) loaded with uniform and non-uniform distribution of 7, 18 and 30 mgr/gr of 79Au, 64Gd, 26Fe and 22Ti in water phantom (30×30×30 cm3) was simulated. Results: DEF of 4.7% to 19.4% and 3.3 to 18.6% were calculated respectively for uniform distribution of 79Au and 64Gd with 7 to 30 mgr/gr concentrations. For non-uniform distribution these values were 0.4%to 1.9% and 0.2% to 1.2%, respectively. Increased dose of the peripheral-health tissue due to presence of 2 to 8.5 mgr/gr of 79Au and 64Gd was estimated from 1.3% to 6.5% and 1.1% to 4.2%, respectively. Conclusion: increase of atomic number and concentrations of NPs enhance the absorbed dose due to increased possibility of photoelectric phenomena. Non-uniform distribution of NPs underestimated dose compared to uniform distribution; therefore, considering accurate NPs distribution inside the tumor volume is crucial to calculation of dose enhancement. Targeted labeling of NPs for the maximum absorption by tumor and for the minimal penetration into peripheral tissues has potential to increase radiation therapeutic ratio

Tumor dose enhancement by nanoparticles during high dose rate 192 Ir brachytherapy

Aims and Objectives: The present study aims to evaluate and compare the dose enhancement factor (DEF) of tumor injected with different nanoparticles (NPs) around high dose rate (HDR) 192 Ir brachytherapy source. Materials and Methods: Monte Carlo calculations were performed with MCNPX code to determine the DEF caused by in tumor injected with 79 Au, 64 Gd, 26 Fe, and 22 Ti NPs during HDR 192 Ir brachytherapy. The uniform and non-uniform distribution of NPs within tumor was modeled with simple NPs-water mixture, and realistic nano-scale-lattice model. Furthermore, a margin of 79 Au and 64 Gd NPs was implemented around the tumor volume. Results: The increased dose caused by uniformly distributed 79 Au and 64 Gd NPs with 7, 18, and 30 mgr/gr concentrations was 4.7, 11.8, 19.4, and 3.3, 8.3, and 18.6, respectively. For non-uniform distribution, it was 0.4, 1.2, 1.9, and 0.2, 0.7, and 1.2, respectively. Increased tumor dose due to 26 Fe and 22 Ti was not significant. The peripheral-healthy tissue dose as margin with 2, 5, and 8.5 mgr/gr of 79 Au and 64 Gd increased by 1.3, 3.6, 6.5, and 1.1, 2.5, and 4.2, respectively. Increase the radial depth of tumor (from 1.5 to 5 cm) increase DEF (up to 22.3). The nano-lattice model underestimated the DEF up to 4 and 3.6 for 79Au and 64 Gd NPs, respectively. Conclusion: Injecting of high-Z gold NPs into tumor increases the absorbed dose of tumor irradiated with 192 Ir HDR brachytherapy source. Size, geometry, concentration, and distribution model of NPs and tumor depth are crucial factors to accurately estimate the DEF. © 2015 Journal of Cancer Research and Therapeutics | Published by Wolters Kluwer - Medknow

Dose perturbation due to the magnetic port of tissue breast expander in patient undergoing the postmastectomy radiation therapy

There is a concern about dose perturbation due to high-Z metallic port of temporary tissue expander (TTE) for patients with breast reconstruction undergoing to the postmastectomy radiation therapy (PMRT). The aim of this study is exactly determination the value of dose perturbation due to the presence of metallic port of TTE. The BEAMnrc code was used to simulate of a 6 MV-Primus Siemens Linac and to calculate the dose due to emerge of magnetic port (McGhan Style 133 model) at different depths in water phantom. The present depth dose and profile curves were calculated. A dose enhancement about 15 at front of the port and a dose reduction of about 10 at 5 cm distance from the backward direction of the port were resulted. The dose reduction at the shadow region of the magnetic port of TTE is significant and must be considered to calculate of accurate dose distribution

Deformation behavior of nano-porous polycrystalline silver. Part II: Simulations

Three-dimensional finite element simulations of nano-porous silver structures are performed to understand the correlation between the porous morphology and the mechanical behavior. The nano structures have been obtained from ptychographic X-ray computed tomography. The simulations allow distinguishing between the interplay and role of the ligament size, the pore morphology and the porosity, and therefore provide a better comprehension of the experimental observations. We show that the proposed model has a predictive character for mechanical behavior of nano-porous silver. (C) 2017 Published by Elsevier Ltd on behalf of Acta Materialia Inc. This is an open access article under the CC BY-NC-ND license

Quality control of acuity-varian radiotherapy simulator system

One of the main and primarily phase to success of radiotherapy is accurately localization of the target volume and health peripheral tissues by radiotherapy simulator. The aim of this study is to investigate the some specific quality control tests necessary to provide adequate confidence of radiotherapy simulator performance Various essential parameters for quality control of Acuity- Varian radiotherapy simulator such as matching of mechanical measurements and electrical readouts, isocenter check, Congruence between optical field and radiation field, laser positioning system, kVp accuracy of X-ray beam, flat panel performance (resolution and low contrast sensitivity), etc were checked by quality control test tools. All investigated tests for matching of mechanical measurements and electrical readouts of field size, rotation and movement of table, gantry and flat panel detector were within the tolerance limits. The accuracy and reproducibility of KV passed the acceptable values. All the lasers were aligned with isocenter. However resolution of flat panel was within tolerance limit but low contrast sensitivity was not passed. The various quality control tests carried out on Acuity-Varian radiotherapy simulator were within recommended limits except the low contrast sensitivity that is in borderline of tolerance

Deformation behavior of nano-porous polycrystalline silver. Part II ::simulations

Three-dimensional finite element simulations of nano-porous silver structures are performed to understand the correlation between the porous morphology and the mechanical behavior. The nanostructures have been obtained from ptychographic X-ray computed tomography. The simulations allow distinguishing between the interplay and role of the ligament size, the pore morphology and the porosity, and therefore provide a better comprehension of the experimental observations. We show that the proposed model has a predictive character for mechanical behavior of nano-porous silver