Boric Acid Concentration Research Articles

ОПРЕДЕЛЕНИЕ СТЕПЕНИ ВОЗДЕЙСТВИЯ РАСТВОРОВ ХИМИЧЕСКИХ ВЕЩЕСТВ РАЗНОЙ КОНЦЕНТРАЦИИ НА РОСТ И РАЗВИТИЕ КУЛЬТУРЫ МИКРОМИЦЕТОВ СЕМ. SAPROLEGNIACEAE «IN VITRO»

In connection with the prohibition of organic dyes (violet K, methylene green, etc.) in fish farming, the article focuses on searching the approach to solving the problem of treating culti-vated aquaculture objects affected by saprolegnium micromycetes by using chemicals that do not have a negative effect on the host organism. There have been presented the experiment results of determining the influence of chemicals solutions (hydrogen peroxide, hydroperite, boric acid, sodium chloride) and the medicinal preparation Monclavit-1 on the culture of micro-mycetes Saprolegniaceae isolated from the incubated caviar. There has been shown the effectiveness of boric acid concentrations from 0.1% to 2.0%; of Monklavit-1 – 0.005-0.03%; of hydrogen peroxide – 
 0.5-0.7%; of hydroperite - from 1.5% to 2%. The maximum fungistatic effect on the growth and development of saprolegnium micromycetes is provided by the chemicals: sodium chloride (4.0% and 4.5% for 5 minutes) and 0.4% solution of hydrogen peroxide with an exposure of 3 minutes. The obtained data suggest that using the above substances, taking into account the effective concentrations and exposures in fish farming, will reduce infection with saprolegnium micromycetes of aquaculture objects at different stages of development (from caviar to producers).

Study on criticality and reactivity coefficients of VVER-1200 reactor

The numerical validation process is one of the important stages in reactor core design. In the present work, the criticality analysis calculations of VVER-1200/V392M reactor core was performed at first and second phases of initial fuel loading in cold, hot, and normal states. The calculations were carried out using MCNP5 transport code with ENDF/B-VII.0 nuclear data library, for core package and data library validation. The effect of different boric acid concentrations and the variation of coolant temperature and density, on the effective multiplication factor were investigated. Good agreements were observed between the previous measured values and the present calculated results of the effective multiplication factor. Furthermore, a preliminary limit for the boric acid concentrations at normal reactor operation state was deduced, along with full analysis of the reactivity coefficients of fuel and coolant temperatures, void, and boron concentrations. The analysis represents one of the first studies at which Monte Carlo transport code MCNP is accurately employed in modeling VVER-1200.

Uncertainty Analysis of WWER-1000 Core Macroscopic Cross Sections due to Spectral Effects

The paper presents the results of uncertainty analysis of WWER‑1000 core macroscopic cross sections due to spectral effects during WWER‑1000 fuel burnup and the analysis of cross section sensitivity from thermophysical parameters of the calculated cell, which affect energy spectrum of neutron flux density.
 The calculation of changes in the isotopic composition during burnup and the preparation of macroscopic cross sections used the developed HELIOS computer model [1] for TVSA, which is currently operated at most Ukrainian WWER‑1000 units.
 The GRS approach applying Software for Uncertainty and Sensitivity Analyses (SUSA) [2] was chosen to assess the uncertainty of the macroscopic cross sections due to spectral effects and analysis of cross section sensitivity from thermophysical parameters. The spectral effect on macroscopic cross sections was taken into account by calculating the fuel burnup for variational sets of thermophysical parameters (fuel temperature, coolant temperature and density, boric acid concentration) prepared in advance by the SUSA program, as a result of which fuel isotopic composition vectors were obtained. After that, neutronic constants for the reference state were developed for each of the sets of isotopic composition, which corresponded to a certain set of thermophysical parameters.
 At the next stage, the uncertainty of macroscopic cross sections of the interaction due to the spectral effects on the isotopic composition of the fuel was analyzed using SUSA 4, followed by the analysis of cross section sensitivity from thermophysical parameters of the calculated cell affecting energy spectrum of neutron flux density. In the future, the uncertainty of two-group macroscopic diffusion constants can be used to estimate the overall uncertainty of neutronic characteristics in large-grid core calculations, in particular, in the safety analysis.

Stretch-induced structural evolution of dichromatic substance with poly (vinyl alcohol) at different concentrations of boric acid: An in-situ synchrotron radiation small- and wide-angle X-ray scattering study

The evolution of poly (vinyl alcohol) PVA structure and dichromatic substance induced by uniaxial stretching PVA in the mixed solution with iodine and boric acid (BA) is systematically studied by the combination of in-situ synchrotron radiation small- and wide-angle X-ray scattering (SAXS and WAXD). The experiment is carried out under an orthogonal experimental design for the iodine concentrations of 0.01, 0.2, 1 M, and the BA concentrations of 0.3, 1, and 3 wt%, respectively. We divide the stretch process into three regions, whose boundary is the yield point and strain harden point. The PVA-I3- co-crystal generating at high and moderate iodine concentrations is less stable as compared with the PVA crystal, which leads to the earlier decrease of crystallinity at the end of the first region. In the second region, the broken crystal, namely the regular amorphous, is the precursor of the PVA-polyiodide complex. Further increasing the strain, the PVA-I3- co-crystals are generated from the one dimension polyiodide surrounded by the PVA chains through a melt-reconstruction process. The adequate BA can make it easy to form the polyiodide at the initial state. Still, the increasing rate of polyiodide is suppressed by further added BA due to the limitation of chain movement by the crosslinking agent. In the final region, the emergence of nanofibril can account for the strain hardening of the film. The evolution of polyiodide and PVA-I3- co-crystal revealed by this work gives a better understanding of the polarizer production process, which may guide the resolution of blue leakage of polarizer via an enhancement of the I3− in the crystal form during stretching.

Standardization of chemicals for improving post harvest life of loose flowers of tuberose (Polianthes tuberosa)

An experiment was carried out to study the effect of various concentrations of boric acid and sodium benzoate on post harvest life of loose flowers of tuberose for three years from 2016 to 2018 under AICRP on Floriculture. The experiment was laid out in completely randomized design with four replications consisting eight treatments of chemicals, viz. boric acid (2, 3, 4 and 5%), sodium benzoate (10, 25 and 50 ppm) and control. The results of pooled analysis of three years indicated that the florets (loose flowers) of tuberose treated with 4% boric acid significantly improved the post harvest life with the minimum change in fresh weight of florets (6.91, 17.38, 29.67 and 45.74% ), maximum fresh flower (98.67, 81.00, 56.00 and 35.00%) at 12, 24, 36 and 48 hours, respectively. Application of 4% boric acid also recorded significantly maximum number of opened flowers (5.17), half opened flowers (4.67) as well as minimum closed flowers (15.17) at 48 hr out of 25 flowers. The maximum longevity (39.33 hr), minimum rotting at 48 hr (40.25%) and highest score of acceptability at 36 hr as per hedonic scale (8.05) were also recorded in the same treatment. Quick dip of loose flowers of tuberose in 4% boric acid was found beneficial for improving post harvest life of loose flowers with 56% fresh up to 36 hr.

Experimental modelling of mass transfer of boric acid with steam at parameters characteristic for VVER reactors in emergency mode

The paper presents experimental data obtained during the study of the mass transfer of boric acid with steam at a pressure of 0.1-0.3 MPa in the concentration range of 16-440 gkg−1 H2O. The volatility of boric acid in a range of parameters typical for a possible emergency at the VVER nuclear power plants (NPPs) was studied using the test facility. As a result, new experimental data on the change in the concentration of boric acid in steam during its boiling were obtained. The range of applicability of the dependence for determining the distribution coefficient of H3BO3 between the steam and the boiling coolant has been expanded.

Microstructural properties, thermal insulation and thermal degradation behavior of boron‐containingmonolithic novolac xerogels

AbstractEnhancement of thermal stability‐insulation performance of hyper porous materials is the premier issue to design of novel porous thermal protection systems. Boron‐containing monolithic novolac xerogels (BCNXs) were synthesized using sol–gel networking of novolac resin with hexamethylenetetramine (HMTA) and boric acid at the solvent saturated vapor atmosphere (SSVA). The aim was to elucidate the effect of higher crosslinking density and thermal stable boron containing chemical bonds on the microstructure, thermal conductivity, and thermal oxidation stability of novolac xerogels. The results of FESEM and BET analysis showed that the microstructural characteristics of xerogels are significantly depend on the HMTA and boric acid concentration. The thermogravimetric results were analyzed using characteristic kinetic temperature (CKT)‐characteristic kinetic temperature range (CKTR) approximations. The effect of micromorphology of xerogels on the thermal conductivity was investigated. The effective thermal conductivity of samples were in the range of 0.031–0.048 W/m K.

Effect of a Boric Acid Corrosive Environment on the Microstructure and Properties of Concrete.

Boric acid, a weak acid, is often used to shield neutrons in water cooling systems in nuclear power stations. The leakage of boric acid in water cooling systems damages the concrete structure and affects the safety of nuclear power engineering. In this experiment, concrete specimens were cured with boric acid at 20, 40, and 70 °C to study the effect of boric acid on the microstructure and properties of concrete. X-ray diffraction (XRD) and thermogravimetry and differential scanning calorimetry (TG-DSC) were used to analyze the change in mineral composition. The microstructure was examined by scanning electron microscope (SEM). The porosity of the concrete was examined by mercury intrusion porosimetry (MIP). The results show that the performance of specimens was stable under the curing conditions of 20 and 40 °C. Under the curing environment of 70 °C, the performance of concrete cured with 0, 2000, and 7000 ppm concentrations was stable, but the compressive strength of the 180,000 ppm specimen was reduced by 27.8% and suffered the most serious loss of mass and surface corrosion, with the most harmful pores. The high concentration of boric acid seriously damaged the surface structure of concrete, which is the main reason for its loss of properties. This situation is extremely dangerous in nuclear power engineering, so the effect of boric acid leakage cannot be ignored.

A new approach of spectral regulation in the pressurized water reactors using Zr rods

The elongation of the fuel cycle period and the reactor reactivity control are crucial for all reactor suppliers. The traditional methods of boric acid, burnable absorbers, and control rods to control the reactor reactivity have their defects. A new method of the neutron spectral shift is studied to perform the reactor reactivity control and maintain the length of the fuel cycle. The neutron spectrum regulation can be achieved with different methods, including the Zr rods insertion in the fuel assemblies as water displacers. In this work, SERPENT2 version 2.1.30 was used to investigate a new fuel assembly design in the basics of Sierpinski carpet geometry to utilize the Zr rods as water displacers. The study of different fuel pitches of the Sierpinski fuel assembly is investigated to choose the reference fuel of the new design. The effect of boric acid concentration increasing and defining the maximum boric acid concentration in the Sierpinski fuel assembly are studied. The primary safety parameters of the Doppler effect and moderator temperature reactivity coefficients calculations approved the safety of the new Sierpinski fuel assembly design. The infinite multiplication factor at different steps of burnup showed the efficiency of the Sierpinski fuel assembly model to control the reactor reactivity. The average breeding factor to the burnup limit of 65 GWd/T is 0.68 in the Sierpinski fuel assembly with the presence of Zr rods.

Determining the critical concentration of boric acid and the time of its onset when reaching to minimum controllable power for VVER

Startup to minimum controllable power level (criticality approach) is one of the most hazardous nuclear operations during operation. In particular, the spontaneous and unauthorized startup to minimum controllable power is very dangerous, and it occurs as a result of some technological operations or changes in technological regimes. Currently, there are codes for neutron-physical calculations at NPPs with VVER, such as reactor simulator (IR) and BIPR-7A. These codes calculate the boric acid critical concentration without relying on excore ionization detectors data, which may result in inaccuracies in determining the critical concentration. In addition, feeding the primary circuit with clean condensate must be stopped at least 15 minutes before is reached, and these codes do not calculate the time to reach the critical state. As a result, the idea arose to develop a code that would predict the time to reach the critical state and the critical concentration of boric acid only using the measuring equipment readings without reliance on additional calculations.

Effect of addition of boric acid on thermo-mechanical properties of microcrystalline cellulose/polyvinyl alcohol blend and applicability as wood adhesive

Although the wood adhesive uses cellulose as a cheap and bio-degradable reinforcing agent, the usage is restricted because of its inability to enhance tackiness and adhesion compared with conventional wood adhesives. In this study, microcrystalline cellulose (MCC) incorporated polyvinyl alcohol (PVA) was prepared by blending in water. The availability of free hydroxyl groups in MCC and PVA offers a site for further modification. To upgrade cellulose as a functional filler, crosslinking approach can be a possible solution. Here boric acid is investigated as a crosslinker to improve the mechanical and thermal properties of PVA/MCC blend. Various analytical methods were employed to quantify the effect of crosslinking namely viscosity measurement, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and water contact angle measurement. DSC result shows a shift in glass transition temperature with the increasing concentration of boric acid. From DMA results, the storage modulus at 100 °C doubled when 0.2 wt.% boric acid was added, compared to the blank sample. Additionally, the thermogram of tan delta exhibited a shift to higher temperatures with peak broadening on increasing boric acid concentration, which confirmed enhancements in thermo-mechanical properties. Moreover, crosslinking enhanced adhesive performance property. It was observed that the sample crosslinked with 0.2 wt.% boric acid showed the best result with two times increment in bonded tensile shear strength on wood substrate after 6 and 24 h of testing.

Method transfer assessment for boric acid assays according to different pharmacopoeias' monographs

The background of this study was transfer assessment for H3BO3 assays according to different pharmacopoeias’ monographs and verification of the crucial parameters—the polyols’ excess (mannitol, glycerine, sorbitol), the initial H3BO3 concentrations and the indicator’s concentrations. The purpose of the work was the comparative study according to different pharmacopoeias: the European (EP 9), the American (USP 35-NF 30), the Japanese (JP XVII), important for quality control of H3BO3, as an active component or an excipient. pH analyses were set up to establish the effects of selected polyols and the initial H3BO3 concentrations. For evaluation of assay results and methods’ equivalence, standard t test and two one-sided t test (TOST) were applied. Pharmacopoeias’ procedures propose volumetric analyses by 1 M NaOH standard solution with visual end-point detection (phenolphthalein) using sufficiently high H3BO3 concentrations and less excess of polyols, as the good alternative to potentiometric method. The influence of phenolphthalein’s concentration (0.1%, 1%), evidenced as relevant factor, caused the difference shown by standard t test: 99.82% (EP 9) and 99.66% (JP XVII). Equivalences between three methods were confirmed by TOST procedures with defined acceptance criterion ± 2% derived from the mean value (99.83%). The comparative study results pointed out that the initial phenolphthalein’s concentration was the crucial influencing factor on harmonization of assay mean values, which was confirmed by TOST application for the methods’ equivalency in method transfer evaluation. The best possible correlation between the lowest excess of polyol-sorbitol and the highest initial boric acid concentration was proved by JP XVII, which was indicated by pH-metric analyses.

Evaluation of shielding efficiency of using boric acid as coolant in CFETR vacuum vessel

Vacuum vessel is a hermetically sealed steel container made up of double steel walls and in-wall shielding, which shields the neutron and protects other components in fusion reactor. Cooling water circulates through the vessel's double steel walls and removes the heat generated during operation. Since boron-10 has a large neutron absorption cross-section, boric acid is supposed to have better shield effect than the original cooling water. In this paper, the effectiveness of pure water and boric acid watery solution as coolant between the double steel walls of the vacuum vessel of CFETR is evaluated by Monte Carlo method. In the simulation, shield efficiency of pure water and different concentration of boric acid is investigated. Neutronic characteristics including neutron flux and neutron spectrum have been calculated. The result shows that boric acid can significantly reduce the flux of total neutron, while the flux of fast neutron takes less change. In conclusion, boric acid has better neutron shielding efficiency than water and can make total neutron flux decline 35%.

Growth parameters and plant biomass of tomato evaluated under different concentrations of boric acid

The objective of this study was to investigate the growth parameters and plant biomass of tomato (Solanum lycopesicum) evaluated under different levels of boric acid, major source of boron. The treatments were; Normal nutrient solution (control, boric acid conc. = 0.000308 g l-1); nutrient solution in which the concentration of boric acid increased by the factor of 5 (boric acid x5, boric acid conc. = 0.00154 g l-1); and nutrient solution in which the concentration of boric acid was increased by the factor of 10 (boric acidx10, boric acid conc. = 0.00308 g l-1). Morphological attributes determined were shoot height, number of leaves, leaf area, shoot, leaf and root fresh and dry weight, and growth indices. Shoot height, number of leaves, leaf area, shoot, leaf and root fresh and dry weight, and growth indices in the seedlings treated with boric acid increased by factor of 10 (boric acid x10)were greater than other treatments. It can be concluded that nutrient solution of boric acid increased by a factor of ten improve the growth parameters and plant biomass of tomato.

Corrosion resistance of 5005 aluminum alloy by anodizing treatment in a mixture of phosphoric and boric acids

The corrosion resistance of 5005 aluminum alloy was improved by anodizing treatment in a mixture electrolyte of phosphoric acid and boric acid. The influence of anodizing parameters on the corrosion resistance of the studied alloy has been investigated. For example, the effect of the concentration of phosphoric acid, concentration of boric acid, voltage and time of anodization. In this work, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) were used to study the corrosion behavior of the aluminum alloy. Scanning electron microscopy (SEM) method was used to study the surface of the aluminum alloy before and after anodization. The obtained results show that the anodizing treatment of 5005 aluminum alloy in phosphoric-boric acids provides better corrosion resistance in comparison with the anodizing treatment in phosphoric acid.

Core analysis of accident tolerant fuel cladding for SMART reactor under normal operation and rod ejection accident using DRAGON and PARCS

There has been a deep interest in trying to find better-performing fuel clad motivated by the desire to decrease the likelihood of the reactor barrier failure like what happened in Fukushima in recent years. In this study, the effect of move towards accident tolerant fuel (ATF) cladding as the most attracting concept for improving reactor safety is investigated for SMART modular reactor. These reactors have less production cost, short construction time, better safety and higher power density. The SiC and FeCrAl materials are considered as the most potential candidate for ATF cladding, and the results are compared with Zircaloy cladding material from reactor physics point of view. In this paper, the calculations are performed by generating PMAX library by DRAGON lattice physics code to be used for further reactor core analysis by PARCS code. The differential and integral worth of control and safety rods, reactivity coefficient, power and temperature distributions, and boric acid concentration during the cycle are analyzed and compared from the conventional fuel cladding. The rod ejection accident (REA) is also performed to study how the power changed in response to presence of the ATF cladding in the reactor core. The key quantitative finding can be summarized as: 20 °C (3%) decrease in average fuel temperature, 33 pcm (3%) increase in integral rod worth and cycle length, 1.26 pcm/°C (50%) and 1.05 pcm/°C (16%) increase in reactivity coefficient of fuel and moderator, respectively.

Boric acid enhances Metarhizium anisopliae virulence in Blattella germanica (L.) by disrupting the gut and altering its microbial community

Extensive use of insecticides has caused widespread resistance in German cockroach (Blattella germanica) populations on a global scale. Biological control has potential to mitigate insecticide resistance, and Metarhizium anisopliae, an entomopathogenic fungus, has shown good efficacy against cockroaches alone and in combination with various insecticides, including boric acid. To investigate the mechanism(s) that underlie synergism between M. anisopliae and boric acid, we conducted dose-response assays with combinations of fungus and boric acid fed to cockroaches and histological observations of the midgut and we characterized the gut microbiome of treated cockroaches. The combination treatments were synergistic with co-toxicity factors >20 at 4 out of 12 treatments and LT50 values of 5 days at the highest concentration of boric acid. M. anisopliae reached the hemocoel faster when it was ingested with boric acid, likely because boric acid disrupted the epithelial cells of the midgut. The gut microbiome was also altered by these treatments. The abundance of Parabacteroides and Enterococcus, with known anti-inflammatory and antifungal activity, declined in boric acid and combination treatments, whereas Weissella, an opportunistic pathogen, significantly increased in these treatments. We conclude that two major mechanisms underlie this synergism: (1) boric acid facilitates the penetration of M. anisopliae by physically and chemically disrupting the midgut, and (2) by altering the gut microbiome, boric acid promotes survival and virulence of M. anisopliae in the harsh gut environment.

Effect of Boron on Pollen Attributes in Different Cultivars of Malus domestica L.

The effect of varying boron concentrations on in vivo pollen germination and tube penetration in four different apple cultivar crosses among ‘Golden Delicious,’ ‘Red Delicious,’ ‘Gala’ and ‘Fuji’ was evaluated. Boric acid (H3BO3) with two different concentrations: 1000 and 2000 mg L−1, was sprayed on the foliage long before the onset of flowering. Pollen–pistil interaction vis-a-vis pollen germination and tube penetration was evaluated using fluorescence microscopy technique, 72 and 120 h after manual pollination. Among different crosses, ♀Golden delicious × Red delicious♂ treated at 1000 mg L−1 concentration of boric acid showed maximum (27.39%) pollen germination and pollen tubes at different levels inside the style. In control without boron, only 6.49% germination was observed. Interaction of boron conc. × time depicted maximum pollen germination and tube number 120 hap. The present study demonstrates that foliar application of boron beyond 1000 mg L−1 on different apple cultivars reduces germination of pollen and development of pollen tubes down the style.

Hydration Effect of Boric Acid on the Strength of High-Performance Concrete (HPC)

Boron compounds are commonly used as a cementitious composite material for the attenuation of neutron and gamma radiation in HPC-M40. Boron compounds play a major role in the concrete for radiation shielding properties but addition of boric acid (H3BO3) to concrete drastically reduce hardening and strength. Commonly for radiation shielding of high thermal neutron boron based materials used in high purity concrete. In this study, different percentages of boric acid 1, 2, 3, 4 & 5% were added to the high-performance concrete (HPC) and the effects on hydration process and strength were determined. Boron compounds will modify the active sites in the cement material and increase the setting time. The hydration of cement in addition to boric acid in the high-performance concrete has been studied using, X-ray diffraction, Fourier Transfer Infrared Spectrometry (FT-IR) and Field Emission Scanning Electron Microscopy (FESEM). The addition of boric acid concentration into the concrete specimen it is very strength til 60th day of curing. At the end of curing days compressive strength dramatically improved.

Clean the Ni-Rich Cathode Material Surface With Boric Acid to Improve Its Storage Performance.

The existence of residual lithium compounds (RLCs) on the surface of layered Ni-rich materials will deteriorate the electrochemical properties and cause safety problem. This work presents an effective surface washing method to remove the RLCs from LiNi0.90Co0.06Mn0.04O2 material surface, via ethyl alcohol solution that contains low concentration of boric acid. It is a low-cost process because the filter liquor can be recycled. The optimal parameters including washing time, boric acid concentration, and solid–liquid ratio were systematically studied. It has been determined by powder pH and Fourier transform infrared spectra results that the amount of RLCs was reduced effectively, and the storage performance was significantly enhanced for the washed samples. The 150th capacity retentions after storing had increased from 68.39% of pristine material to 85.46–94.84% of the washed materials. The performance enhancements should be ascribed to the surface washing process, which removed not only the RLCs, but also the loose primary particles effectively.