Activation and transmutation of tungsten boride shields in a spherical tokamak

The FISPACT-II code is used to compute the levels of activation and transmutation of tungsten borides for shielding the central High Temperature Superconductor (HTS) core of a spherical tokamak fusion power plant during operations at 200 MW fusion power for 30 years and after shutting down for 10 years. The materials considered were W2B, WB, W2B5 and WB4 along with a sintered borocarbide B0.329C0.074Cr0.024Fe0.274W0.299, monolithic W and WC. Calculations were made within shields composed of each material, for five reactor major radii from 1400 to 2200 mm, and for six 10B isotope concentrations and at five positions across the shield. The isotopic production and decay in each shield is detailed. The activation of boride materials is lower than for either W or WC and is lowest of all for W2B5. While isotopes from tungsten largely decay within 3 years of shut-down, those from boron have a much longer decay life. An acceptable 70% of the absorbing 10B isotope will remain after 30 years of operations behind the first wall for a 1400 mm radius tokamak. Gaseous production is problematic in boride shields, where 4He in particular is produced in quantities 3 orders of magnitude higher than in W or WC shields. The FISPACT-II displacements per atom (dpa) tend to increase with boron content, although they decrease with increased 10B isotopic content. The dpa ranges of boride shields tend to lie between those of W and WC. Overall, the results confirm that the favourable fusion reaction shielding properties of W2B5 are not seriously challenged by its irradiation and transmutation properties, although helium gas production could be a challenge to its thermal and mechanical properties.

Influence of boron doping on characteristics of glucose based hydrothermal carbons

In this study, the influence of boron doping on structural and surface properties of carbon material synthesized by hydrothermal method was investigated, and the obtained results were compared with the previously published influence that boron has on characteristics of carbonized boron-doped hydrothermal carbons (CHTCB). Hydrothermal carbons doped with boron (HTCB), were obtained by hydrothermal synthesis of glucose solution with the different nominal concentrations of boric acid. It was found that glucose based hydrothermal carbon does not have developed porosity, and the presence of boron in their structure has insignificant influence on it. On the contrary, additional carbonization increases the specific surface area of the undoped sample, while the increase in boron content drastically decreases specific surface area. Boron doping leads to a decrease in the amount of surface oxygen groups, for both, hydrothermally synthesized and additionally carbonized material. Raman analysis showed that boron content does not affect the structural arrangement of HTCB samples, and Raman structural parameters show higher degree of disorder, compared to the CHTCB samples. Comparison of structural and surface characteristics of hydrothermal carbons and carbonized materials contributes to the study of the so far, insufficiently clarified influence that boron incorporation has on the material characteristics.

Modelling the tribological response in dry sliding of boron modified as-cast Ti6Al4V on hardened steel

Tribological characteristics of boron modified as-cast Ti6Al4V alloys are not very well known, but these alloys enjoy improved as-cast mechanical properties and favourable manufacturing economy. Experimental results are reported here for the effects of sliding speed and normal load on the wear rate and the coefficient of friction in dry sliding of these alloys on hardened EN 31 steel. Alloys having 0%, 0.30%, and 0.55% boron by weight were tested. A full factorial experiment assessed the effects of boron content, speed, and load on wear and friction. Interactions between speed and load were found to be statistically significant in influencing the wear rate and the coefficient of friction. Regression models are developed to predict the wear rate and coefficient of friction responses. The developed contour plots can assist designers in choosing operating conditions when selecting these alloys even if the wear mechanisms are unknown. Evidence shows that the wear resistance of Ti6Al4V can be improved by boron addition, and wear regimes are sensitive to boron content.

Computer simulation of boronizing kinetics for a TB2 alloy

The boron diffusion at the surface of a TB2 alloy was simulated via two mathematical models relying on the numerical resolutions of the system of differential algebraic equations (DAE) for the integral method and ordinary differential equations for the mean diffusion coefficient (MDC) method. Both approaches allowed us to compute the boron diffusion coefficients in TiB2 and TiB for a maximum boron content of 31.10 wt.-% in TiB2 at 1223, 1273, 1323 and 1373 K. The boron activation energies in TiB2 and TiB were evaluated and compared with the data published in the literature. Finally, an experimental validation of both models was made through a comparison of the thicknesses of the experimental layers with the predicted values. Consequently, the simulated thicknesses were in line with the experimental values.

Study on a High-Boron-Content Stainless Steel Composite for Nuclear Radiation

In this research, a high-boron-content composite material with both neutron and γ rays shielding properties was developed by an optimized design and manufacture. It consists of 304 stainless steel as the matrix and spherical boron carbide (B4C) particles as the functional particles. The content of B4C is 24.68 wt%, and the particles’ radius is 1.53 mm. The density of the newly designed material is 5.17 g·cm−3, about 68.02% of that of traditional borated stainless steel containing 1.7 wt% boron, while its neutrons shielding performance is much better. Firstly, focusing on shielding properties and material density, the content and the size of B4C were optimized by the Genetic Algorithm (GA) program combined with the MCNP program. Then, some samples of the material were manufactured by the infiltration casting technique according to the optimized results. The actual density of the samples was 5.21 g cm−3. In addition, the neutron and γ rays shielding performance of the samples and borated stainless steel containing 1.7 wt% boron was tested by using an 241Am–Be neutron source and 60Co and 137Cs γ rays sources, respectively, and the results were compared. It can be concluded that the new designed material could be used as a material for nuclear power plants or spent-fuel storage and transportation containers with high requirements for mobility.

The optimization of table beet cultivation by using a boron-containing chelate

In the field experiment, the possibility of optimizing the cultivation of table beet Beta vulgaris L. using a borate complex based on ethylenediamine disuccinic acid (B-EDDS) was investigated. Before sowing, beet seeds were soaked for a day in a solution of this compound, as well as in solutions of boric acid and a borate complex based on ethylenediaminetetraacetic acid (B-EDTA), taken for comparison, with a concentration of solutes of 1.5·10-3 mol/L. During the growing season, the plants were sprayed twice with experimental solutions at a rate of 100 ml/m2. In the first decade of August, the content of photosynthetic pigments in plant leaves and microbial carbon in the soil was determined, after harvesting, sugars and betanin in root crops were determined by spectrophotometric methods. The boron content in beet root crops was analyzed by the fluorometric method. According to the results of the two-year experiment, all three boron-containing compounds, to varying degrees, had a positive effect on the experimental plant. In decreasing efficiency, they can be arranged in a row: B-EDDS > H3BO3> B-EDTA. Treatment with the solution of borate-ethylenediamine disuccinate complex increased the boron content in root crops by 65% in comparison with treatment with boric acid. In comparison with the control variant, the sugar content in root crops increased by 37%, the content of betanin increased by 25% and the yield of root crops increased by 39%. At the same time, the mass of microbial carbon in the soil increased by 20%, which serves as one of the arguments confirming the ecological safety of the compound under study. Judging by the results of the experiment, borate-ethylenediamine disuccinate has good prospects for use as boron micronutrient fertilizer.

Comparative characterization study of plant based calcium vs synthetic calcium

Calcium is an essential mineral which supports bone health as well as serves as a major therapeutic intervention that can prevent and delay the incidence of osteoporosis.Multicellular aquatic plants like are a rich source of plant based calcium. The Characterization of Plant based calcium and Synthetic calcium sources using sophisticated analytical techniques. Plant based Calcium and Synthetic Calcium sources were subjected to instrumental analysis such as SEM, ICP-OES and XRD, and comparisons were done followed by interpretation.In this study, three different instrument techniques like SEM, ICP-OES and XRD were used for the characterization of plant based calcium and synthetic calcium. The results showed that plant based calcium were smaller crystals as compared to synthetic calcium crystals. Further, in case of XRD results, plant based calcium is shown to possess two 2θ values, whereas in case of synthetic calcium, it showed a single 2θ value. Further, Magnesium and Boron content were higher in case of plant based calcium as compared to synthetic calcium. Both Plant based and Synthetic Calcium can be distinguished using SEM, ICP-OES and XRD techniques. Outcomes of this study enlightens the probable reasons for enhanced bioavailability in case of plant based calcium sources as compared to synthetic sources.