Feasibility Study of Copper-64 Radioisotope Production by Secondary Fast Neutron Bombardment

As a beta and positron emitter, copper-64 (Cu-64) has been coined a theranostic agent in nuclear medicine. Copper-64 is generally produced by bombarding a nickel-64 target with a proton beam via 64Ni(p,n)64Cu nuclear reaction. In this work, secondary fast neutrons are proposed to produce Cu-64 radioisotope via 64Zn(n,p)64Cu nuclear reaction. The secondary fast neutrons were produced by a 10 MeV proton-irradiated primary titanium (Ti) target simulated using the PHITS 3.16 code. In the simulation, the Ti target thickness was varied from 0.01 to 0.1 cm to obtain the optimum secondary fast neutron flux, which was calculated in the rear, radial, and front directions. The Cu-64 radioactivity yield was then computed using the TENDL 2019 nuclear cross-section data. Also, the expected radioactive impurities during Cu-64 production were predicted. The simulation results indicated that the total fast neutron flux resulted from the 10-MeV proton bombarded Be target was 1.70x1012 n/cm2s. The maximum integrated Cu-64 radioactivity yield was 2.33 MBq/µAh when 0.03 cm thick Ti target was shot with 10-MeV protons. The most significant impurities predicted during the bombardment were radioactive isotopes e.g., Co-61, and Zn-65, with the total radioactivity yield estimated to be 0.28 Bq/µAh.

Particleboard from kemenyan wood and belangke bamboo: effect of particle pre-treatment in acidic solution

Dimensional stability is a significant problem in particleboard. This study aims to analyze the effect of immersing particles in an acid solution on particleboard’s physical and mechanical properties made of kemenyan (Styrax sumatrana) wood and belangke (Gigantochloa pruriens) bamboo. The particles were immersed in each acid solution for 24 h, and then dried to reach 9% water content. The particleboard was made with a 25x25 cm2 with a target thickness and density of 1 cm and 0.70 g/cm3, respectively. After being made into sheets, the next step is hot pressing using a hot press machine that has set the temperature, time, and pressure at 160 °C, 5 min, and 30 kg/cm2, respectively. The results showed that immersion in the acid solution can stabilize the dimensions of the resulting particleboard but does not reduce the strength of the board. Several board properties have met the standards, such as density, thickness swelling, modulus of rupture, and internal bond.

The influence of particle soaking in acetic acid and NaOH solutions on the quality of sandwich particleboard from raru wood and belangke bamboo

As a composite product, particleboard has disadvantages related to low dimensional stability. The research purpose was to analyze the effect of immersion in acetic acid and NaOH solution on the quality of the particleboard sandwich. Sandwich particleboard (SPb) was made in a size of 25 cm length and 25 cm width. The target thickness and density are 1 cm and 0.75 g/cm3, respectively. The adhesive used was isocyanate adhesive with a content of 7%. First, The particles, which were in the form of wood shavings and bamboo strands, were soaked in a solution of acetic acid and NaOH at various concentrations (0, 1, 2, and 3%). The moisture content of the particles to be made SPb was set at 7%. After evenly mixing the particles (wood shavings and bamboo strands) and the adhesive, the sheet was created. The board sheets were made into three layers, namely 40% face layer in the form of a bamboo strand, 20% core layer in the form of wood shavings, and 40% back layer in the form of the bamboo strand. The next stage was the hot pressing process at 160 °C for 5 min and 30 kg/cm2 pressure. The following process was conditioning the board for seven days. Testing of quality refers to the standard JIS A5908 (2003). The results showed that the immersion of Raru wood particles in acetic acid and NaOH significantly affected the value of density, water absorption, thickness swelling, modulus of elasticity, modulus of rupture, and internal bond. Except for the moisture content on the AA3 and NA2 boards and the internal bond value on the untreated (control) board, all of the panel properties in this study met the standard.

Analytical and FEM Analyses of High-Speed Impact Behaviour of Al 2024 Alloy

The present work investigates the impact behaviour of Al 2024-T3 alloy using FEM analysis performed through LS DYNA software. Johnson–Cookvisco-plastic model is used to study the ballistic impact resistance of target Al alloy impacted by a rigid steel cylindrical projectile. The tensile properties of Al 2024-T3 alloy reported in the literature are used to estimate the J.C. model parameters. Impact velocities within a range of 50 m/s–900 m/s of the projectile were triggered onto Al alloy target thicknesses in the range of 3.18 mm–6.35 mm. To understand the accuracy of the FEM model, an analytical model proposed by Chen et al. for blunt-nosed projectiles on the ductile targets was used to compare with the obtained residual velocities from FEM simulations. It was observed that the ballistic limit velocities have led to the highest energy absorption behaviour of the Al 2024-T3 alloy for an impact velocity of 183 m/s and a 6.35 mm target thickness. The ballistic limit velocities have increased from 97 m/s to 183 m/s for the considered thickness range of 3.18 mm–6.35 mm. The impact failure was observed to have a petalling formation with two petals for thinner targets, while a full-fledged plugging with no petal formation for the 4.00 mm and 6.35 mm target thicknesses was observed.

A Numerical Study of Penetration in Concrete Targets by Eroding Projectiles of Different Materials

Numerical simulations have been performed to examine the effect of three different eroding rod materials on the penetration in concrete targets. Same kinetic energy is delivered to concrete target using cylindrical rods of Aluminium, Iron, and Copper of identical size. Impact velocities have been varied to keep the kinetic energy the same. Penetration characteristics like centerline interface velocity, penetrator deceleration, plastic strain in the target, and energy partitioning during penetration have been studied for the three different penetrator materials. In all three cases, penetration proceeds nearly hydrodynamically. It is seen that even though the steady-state penetration ceases before reaching the hydrodynamic limit, the secondary penetration takes the total penetration beyond the hydrodynamic value. Plastic strain in the target material is a measure of damage beyond the crater produced by penetration. The lateral extent of plastic strain in target is more for Aluminium penetrator compared to the other two. Energy partitioning during penetration provides details of the rate at which energy is entering into the target. Kinetic energy delivered to the target during impact is partitioned into internal energy and kinetic energy of the target. Finally, the influence of target thickness on the extent of plastic strain has been studied. The result shows that Aluminium penetrators inflict maximum damage to targets of finite thickness.

Numerical and experimental investigations on the effect of target thickness and solution treatment on the ballistic behaviour of AA7075 thick plates

The influence of target thickness and solution treatment on the ballistic behaviour of AA7075 targets has been investigated by both numerical and experimental methods. In numerical simulation, the target thickness was varied from 19 to 26 mm and an Ogive nose shaped projectile of 7.62 mm diameter with inlet velocities ranging between 800–875 m/s was considered. In order to justify the numerical observations, high velocity ballistic experiments were conducted on AA7075-T651 and the solution treated plates of various thicknesses (12, 16, 18, 20, 22 and 25 mm). For this experimental study, a deformable form projectile with dimensions of 7.62 × 51 mm and an inlet velocity of 850 ± 20 m/s was used. Microstructures of ballistic test samples were analysed using an optical microscope. Numerical analysis using ABAQUS predicted the minimum thickness required to resist complete penetration to be 20 mm in the case of AA7075 plates in the T651 condition, while experimental results showed it to be 21 mm. In the case of AA7075 solution treated plates, numerical simulation analysis predicted the minimum required plate thickness to resist complete penetration to be 24 mm, while the experimental results showed it to be 23 mm. Post ballistic microstructure analysis revealed that there was no change in the microstructure in the AA7075-T651 condition plates. Solution treated plates showed deformation of grains nearer to the impact region with the formation of adiabatic shear bands. In the case of the T651 plate, the mode of fracture was brittle, resulting in splinters, whereas it was petalling in the case of the solution-treated plates. The numerically predicted depth of penetration on both targets was reasonably close to experimental results with an average of 4% error.

Thermal conductivity of different bio-based insulation materials

To achieve the zero-waste goal as well as sustainability, the use of the raw materials, especially those from nature, and wood in particular, has to be smart, meaning that the resource has to be used to its full potential. Since wood-based industry is associated with high intensity and the generation of a relatively large amount of residues, those residues should be used for the production of useful products, otherwise they will easily be classified as waste and afterwards used as a source of energy. To present a possible solution for wood residues like wood chips, wood particles and bark, we investigated the possibility of using wood and bark residues as constituents for the production of single layer insulation panel with a target thickness of 40 mm and target density of 0.2 g·cm-3. Thermal conductivity was determined using the steady state principle at three different temperature settings. The average thermal conductivities were determined between 49 mW·m-1·K-1 and 74 mW·m-1·K-1. The highest values were determined at boards made from bark, which also had the highest density (0,291 g·cm-3), while the lowest thermal conductivity was observed for boards made from spruce wood particles.

State of the art in breast intraoperative electron radiation therapy after intraoperative ultrasound introduction

Background Breast intraoperative electron radiation therapy (B-IOERT) can be used in clinical practice both as elective irradiation (partial breast irradiation – APBI) in low risk breast cancer patients, and as an anticipated boost. The procedure generally includes the use of a shielding disk between the residual breast and the pectoralis fascia for the protection of the tissues underneath the target volume. The aim of the study was to evaluate the role of intraoperative ultrasound (IOUS) in improving the quality of B-IOERT. Patients and methods B-IOERT was introduced in Trieste in 2012 and its technique was improved in 2014 with IOUS. Both, needle and IOUS were used to measure target thickness and the latter was used even to check the correct position of the shielding disk. The primary endpoint of the study was the evaluation of the effectiveness of IOUS in reducing the risk of a disk misalignment related to B-IOERT and the secondary endpoint was the analysis of acute and late toxicity, by comparing two groups of patients treated with IOERT as a boost, either measured with IOUS and needle (Group 1) or with needle alone (Group 2). Acute and late toxicity were evaluated by validated scoring systems. Results From the institutional patients who were treated between June 2012 and October 2019, 109 were eligible for this study (corresponding to 110 cases, as one patients underwent bilateral conservative surgery and bilateral B-IOERT). Of these, 38 were allocated to group 1 and 72 to group 2. The target thickness measured with the IOUS probe and with the needle were similar (mean difference of 0.1 mm, p = 0.38). The percentage of patients in which the shield was perfectly aligned after IOUS introduction increased from 23% to more than 70%. Moreover, patients treated after IOUS guidance had less acute toxicity (36.8% vs. 48.6%, p = 0.33) from radiation therapy, which reached no statistical significance. Late toxicity turned out to be similar regardless of the use of IOUS guidance: 39.5% vs. 37.5% (p = 0.99). Conclusions IOUS showed to be accurate in measuring the target depth and decrease the misalignment between collimator and disk. Furthermore there was an absolute decrease in acute toxicity, even though not statistically significant, in the group of women who underwent B-IOERT with IOUS guidance.

Experimental and Numerical Study on Strength of Concrete Slabs under High Speed Projectiles

Concrete elements under high-speed projectiles effect has an increasing interest recently. Understanding to what extent the concrete can resists the effect of projectiles, very necessary in design structures in order to save the occupants. The objective of this study is to develop improved numerical model for predicting dynamic response of RC slabs under HSP attack. The present study presents a total of 12 concrete slabs casted and tested under plain and steel reinforcement. Parameters investigated were slab thickness, (50 mm, 100 mm, and 150 mm) and projectile type. Dynamic simulation was performed also and the results obtained have been discussed and compared with experimental response. Generally, it was concluded that penetration depth was controlled by target thickness regardless the steel reinforcement. Good alignment achieved between numerical and experimental date with respect to penetration depth and crater vale.