Irradiated Powder Research Articles

The bioprotective role of irradiated hibiscus against harmful effects of using repeatedly frying edible oil.

Repeatedly frying process of dietary edible oil has a potential role in the generation of free radicals. Therefore, questions have always been raised as to whether, there is an efficient and economical method to reduce the harmful effects of repeated use of frying edible oil. Since hibiscus has been stated to have a wide variety of therapeutic effects, it was important to investigate its properties against harmful effects of free radicals. The current study aspires to find out whether irradiated powder of hibiscus has a protective role against adverse effects of repeated use of frying edible oil. Thirty-five adult male albino rats were equally assigned into five groups. First group"G1" was fed with normal diet as control group, meanwhile, group"G2" the diet mixed with fresh oil, "G3" diet mixed with repeatedly frying oil only, "G4" diet mixed with frying oil treated with hibiscus and "G5" diet mixed with frying oil treated with irradiated hibiscus. Feeding duration was six weeks. Fatty acid analyses of oil as well as peroxide values were determined. Blood and liver samples were collected for biochemical analyses as well as histological study. Repeatedly heated cooked oil has significant increases in peroxide value, acid value, free fatty acid and both conjugated diene and triene compared with repeatedly frying oil treated with hibiscus. Also there are significant increases in cholesterol and triglyceride and impaired in liver functions in "G3"compared with others. In addition, relative to the hibiscus groups, there is a substantial reduction in oxygen consumption in "G3". Both hibiscus as well as irradiated hibiscus attract attention in order to play a vital and economical role against harmful effects of frequent use of frying edible oil on some biological functions but, irradiated hibiscus was more effective.

Mechanical properties of cement mortar with gamma-irradiated recycled plastic powder, pellet, and fiber

This study aimed to investigate the impact of gamma irradiated recycled polyethylene terephthalate (PET) pellets, powder, and fibers on the mechanical performance and ductility of cementitious mortar. The sensitivity to gamma irradiation was explored by varying the irradiation rate and total dose. The recycled PET additives employed in this experiment consisted of pellets and their different application forms: powder and fiber, containing 30 % recycled raw materials polymerized through a chemically recycled method. For comparison, plain mortar composite and virgin PET mortar composite were used as controls. When PET pellets partially replaced the aggregate, the compressive strength of the composite decreased significantly as the volume fraction of pellets increased. Conversely, specimens partially replaced by PET powder showed an overall increase in compressive strength compared to the control specimens, regardless of the volume fraction of powder, gamma irradiation rate, or total dose, with no change in ductility. To assess changes in tensile strength and ductility of the recycled PET fibers under different gamma irradiation rates and total doses, direct fiber tensile tests were conducted. The gamma-irradiated fiber specimens exhibited a slight increase in strength and ductility. This information allowed for the calibration of the tensile material constitutive relationship of PET fibers, which was subsequently used in nonlinear finite element analysis. The study also investigated the variation in direct tensile, compressive, and flexural strengths with different volume fractions of fiber. The results indicated that the strength enhancement was minimal, but the direct tensile and flexural tensile analyses predicted an enhancement.

Intrinsic emissions and formation of electron-hole trapping centres in excited Li2SO4

Vacuum ultraviolet and thermal activation spectroscopies were used to study the nature of intrinsic emission and the mechanisms of the formation of electron and hole trapping centres in irradiated Li2SO4 powders and crystals. The obtained results along with excitation spectra showed that recombination emission at 3.8–4.2 eV and 4.5–5.5 eV occurs when an electron passes from the second and third sub-bands of the valence band formed from the 2p state of oxygen to the conduction band. It has been determined that Li2SO4 electron and hole trapping centres are created when electrons are trapped in the SO42– anionic sites. The holes are localised in the form of SO4 – radicals. The spectral position and intensity of individual emission bands are dependent on the crystallographic arrangement of localised holes.

Use of irradiated PET plastic waste for partially replacing cement in concrete?

Portland cement used in the manufacture of concrete is responsible for an estimated 5–8% of the global CO2 emissions. Recently published work (Schaefer et al., 2018) claims that γ-irradiated PET waste powder can be used as a partial replacement of cement in concrete for reducing its CO2 footprint. More specifically, exposure of PET to γ-irradiation at a dosage of 100 kGy alters its crystal structure and chemical composition, which in turn leads to a smaller reduction in concrete strength compared to non-irradiated PET waste. Hence, making it possible for irradiated PET waste to be used as a raw ingredient in the manufacture of concrete while at the same time diverting significant quantities of PET waste from landfills. The aim of this research was to independently assess and verify the above claims. For this purpose, the effect of different low irradiation dosages (0, 10 and 100 kGy) and different replacement levels (2.5 %, 5 % and 10 % by volume) of cement by PET waste on the consistency and mechanical strength of pastes and mortars was determined in a laboratory investigation. XRD, TGA and DSC were also used to study the effect of irradiation on the microstructure of raw PET waste and the microstructure of paste and mortar samples containing irradiated PET waste powder. Our results indicate that use of γ-irradiated PET waste (exposed to an irradiation dosage of up to 100 kGy) for partially replacing cement does not lead to a significant recovery of mechanical strength lost when non-irradiated PET waste is used.

Thermoluminescence of beta irradiated SrHfO3 powders synthesized by the Pechini-type sol-gel method

Here, we report on the thermoluminescence response of beta irradiated SrHfO3 powders synthesized by the Pechini-type sol-gel process. Powders calcined at 900 °C for 6 and 8h exhibited the orthorhombic phase of SrHfO3. The intensity TL response of SrHfO3 samples, exposed to beta irradiation doses from 0.085 to 1530 Gy, was found to increase with the irradiation dose. The TL signal of both samples showed a linear behavior in the range of 2.55–51 Gy and a sublinear behavior for higher irradiation doses. At the dose of 25.5 Gy, the TL response of the sample processed with a calcination time of 6h had the best repeatability with a standard deviation of 3.48% and the lowest fade (12.85%) in the first 48 h. The Tmax-Tstop process, initial rise method and glow curve fitting by computerized deconvolution were employed to determine the trap distribution and kinetic parameters. The TL glow curves of the samples were conveniently fitted by five glow peaks of first and second orders with activation energies ranging from 0.56 to 0.99 eV. Overall, the TL response of the samples showed to be influenced by the density and distribution of defects, mainly originated by oxygen and cation vacancies.

One‐step fabrication of Li2TiO3 ceramic pebbles using pulsed YAG laser

AbstractA large amount of Li‐containing ceramic breeder pebbles is packed in the solid breeding blanket of a nuclear fusion reactor. Several pebble fabrication technologies have been proposed in previous studies, including wet process, emulsion method, extrusion spheronization, additive manufacturing, and melt process. However, a simple, energy‐effective, and scalable fabrication technology remains to be developed for the automated mass production and reprocessing of used radioactive pebbles post‐operation. Selective laser melting potentially enables the quick and automated fabrication of breeder pebbles. Herein, we employ a high‐power density pulse laser to produce ceramic breeder pebbles. A pulsed YAG laser was irradiated over a lithium metatitanate (Li2TiO3) powder bed in air, and the corresponding temperature was monitored using fiber‐type infrared pyrometers. Spherical Li2TiO3 pebbles were successfully fabricated in a single step with an average diameter of 0.78 ± 0.13 μm and the sintering density of 87.4% ± 5.6% (input power: 7.9 J/pulse). The irradiated Li2TiO3 powder melted and turned spherical under surface tension and rapidly solidified, resulting in uniaxial fine grains and a decrease in the degree of long‐range cation ordering.

Effect of high γ-irradiation dosage on physico-chemical, functional and emulsion properties of almond gum powder

Almond gum is a natural biopolymer produced by Almond tree that is non-toxic, biodegradable, and biocompatible. These features make it suitable for applications in the food, cosmetic, biomedical, and packaging industries. To ensure its wide application in these fields, green modification process is necessary. Gamma irradiation is often used as a sterilisation and modification technique, due to its high penetration power. Thus, evaluating its effects on the physicochemical and functional properties of gum after exposure is important. To date, limited studies have reported the use of high dose of γ-irradiation on the biopolymer. Therefore, the present study demonstrated the effect of a high dose of γ-irradiation (0, 24, 48, and 72 kGy) on the functional and phytochemical properties of almond gum powder. The irradiated powder was studied for its color, packing, functional, and bioactive properties. The results revealed a significant increase in water absorption capacity, oil absorption capacity, and solubility index. However, a decreasing trend was observed in the foaming index, L value, pH, and emulsion stability with the radiation dose. Besides, sizable effects were observed in the IR spectra of irradiated gum. Phytochemical properties were significantly improved with an increase in dose. The emulsion was prepared from irradiated gum powder, where the highest creaming index was observed at 72 kGy and a decreasing trend in zeta potential. These results suggested that γ-irradiation treatment is a successful method to generate desirable cavity, pore sizes, functional properties, and bioactive compounds. This emerging approach could modify the natural additive with distinct internal structure for specific uses in wide range of food, pharmaceutical and other industrial applications.

Influence of Short-Pulse Microwave Radiation on Thermochemical Properties Aluminum Micropowder.

The thermochemical properties of Al micropowder after exposure to microwave irradiation were investigated. The Al micropowder was exposed to microwave irradiation in air with a frequency of 2.85 GHz, a power density of 8 W/cm2, and a pulse duration of 25 ns and 3 µs. The thermochemical parameters of the irradiated metal powders were determined by the method of thermal analysis at the heating in air. It was found that an increase in the duration of microwave pulses and irradiation time leads to the thermal annealing of the metal particles, and the thermal processes of melting and sintering begin to dominate over non-thermal processes. The specific thermal effect of irradiated Al micropowder oxidation increases from 7744 J/g to 10,154 J/g in comparison with the unirradiated powder. The modeling of thermal heating processes of aluminum (Al) micropowder under the action of pulsed microwave radiation has been performed. It is shown that with an increase in the duration of microwave pulses and irradiation time, a significant heating of the Al micropowder occurs, leading to its melting and sintering. The results of modeling on the action of microwave radiation on the Al micropowder were compared with experimental results.

Physics-based computational modeling and time-resolved imaging of plasma plume generated by nanosecond laser interaction with a bed of micro metallic powder

Although continuous lasers see frequent applications in selective laser melting or sintering, lasers with short pulse durations (such as those with nanosecond scale durations) possess potential advantages that may include good spatial resolutions and small heat-affected zones. Previous work on selective laser sintering with nanosecond lasers has been reported, particularly for laser micro sintering. At a sufficiently high intensity, a nanosecond (ns) laser pulse can generate a plasma plume from its irradiated metallic powder bed surface. The plasma plume evolution, such as the pressure it generates on the surface of the powder bed, may significantly influence the sintering process in the powder bed. However, physics-based modeling work for plasma generated by nanosecond-pulsed laser interaction with a metallic micro powder bed has been seldomly seen in literatures according to the knowledge of the authors’. Such modeling work has been reported in this paper for a ~4-ns laser pulse interaction with a cobalt micro powder bed, integrated with time-resolved plasma imaging using an intensified CCD (ICCD) camera with nanosecond scale gate widths for the model validation. For the conditions investigated, the model-predicted plasma plume evolutions agree reasonably well with the ICCD imaging results for the given period of comparison. This has reasonably supported the hypothesis posed in this paper (which has been rarely tested according to the knowledge of the authors’) that a short ns laser pulse-induced plasma from a metallic micro powder bed below the critical temperature can be reasonably well described by solving gas dynamic equations in the gaseous phase together with solving the heat transfer equation in the powder bed condensed phase, where the coupling is via the Knudsen layer (KL) relations for vaporization at the interface between the two phases. The model calculations show that in comparison with the bulk cobalt situation, the ns laser pulse can induce more significant surface vaporization from the cobalt powder bed, leading to a plasma plume with typically higher peak temperatures and densities in the simulated period. The plume can generate a short total pressure pulse with a ~491-MPa peak magnitude on the surface of the powder bed.

Laser-assisted transformation of a phenol-based resin to high quality graphene-like powder for supercapacitor applications

Synthesis of high-quality graphene-like structures by means of an eco-friendly, cost effective, one-step and scalable method is highly sought after. Some of these traits have been successfully addressed in recent studies employing laser irradiation in the synthesis process, however, reports on laser-assisted high-quality graphene growth overwhelmingly rely on the rather costly polyimide precursor. In this study, we report laser-mediated synthesis of high-quality graphene powder, originating from a phenol-based resin. Raman spectroscopy and X-ray diffraction findings suggest turbostratic, i.e., rotationally faulted, stacking of graphene layers, while the porous structure of the produced material is revealed by scanning electron microscopy. X-ray photoelectron spectroscopy was employed to probe the chemical composition of the materials before and after irradiation, and revealed the high C/O ratio value (22.6) in the irradiated powder. Moreover, the potential of these graphene-like structures in energy storage applications are investigated in aqueous supercapacitors, using both three- and two- electrode configurations. The excellent conductivity is validated from both sheet resistance measurements 40Ohmsq-1 and the very low ohmic losses during galvanostatic charge discharge measurements. The two-electrode device showed a capacitance of 17.2 Fg−1 at 10 mVs−1, a fairly good rate performance 67% up to 200 mVs−1 and excellent cycling stability (87.2% after 20,000 cycles).

Measurements of the emanation of 37Ar and 39Ar from irradiated rocks and powders

Measurements of the emanation of 37Ar and 39Ar from irradiated rocks and powders

Effect of storage time on the microbial and physicochemical properties of gamma irradiated turmeric powder under various atmospheres of packaging

Irradiation process has recently found a special place in reducing microbial contamination of foodstuffs. However, there are still ambiguities about the effect of irradiation on the physicochemical properties and bioactive compounds of foods during storage. In this study, the influence of gamma irradiation at doses 0, 5, 10, and 15 kGy on the microbial load and physicochemical properties of turmeric powder were studied during one year storage at room temperature under air and modified atmosphere (vacuum and N2). The results showed that irradiation effectively reduced the microbial contamination of turmeric powder and it could provide the safety and microbial desirability of the samples for 1 year at 10 kGy dose. By increasing the storage time and progress of oxidation processes, phenolic compounds (PCs) decreased in all samples. Subsequently, the curcumin, dimethoxycurcumin and bisdemethoxycurcumin contents as curcuminoids were diminished 61.5, 62.1, and 59.1% after one year of storage, respectively. The IC50 (DPPH•, FRAP, and ABTS•+) of the extracts were in the range of (117.9–244.5 μg/ml), (41.5–85.3 μg/ml), and (206.4–505.2 μg/ml), respectively during 12 months of storage and the highest antioxidant activity of the extracts was obtained after four months of storage at a dose of 10 kGy (p < 0.05). These results confirm that the effect of storage time on the physicochemical properties of turmeric powder was higher than the effect of irradiation and packaging atmosphere.

Thermoluminescence dosimetric characteristics of terbium doped barium metaborate phosphors

Rare earth doped barium metaborate (BaB2O4) polycrystalline phosphors were synthesized by the solid-state method. Among these, the BaB2O4:Tb phosphor showed a favorable thermoluminescence (TL) glow curve with good sensitivity. TL dosimetric characteristics were studied for BaB2O4:Tb by optimizing the concentration of the Tb dopant at 0.45 mol%. The powder XRD results confirm the formation of stable crystalline material with rhombohedral structure. The TL glow curve of gamma irradiated powder samples revealed two major peaks at 485 K and 620 K. The gamma dose response of this phosphor has been studied from 200 mGy to 20 kGy. For the 485 K peak, the response is found to be linear up to 1 Gy, then there is a supralinearity up to 250 Gy followed by a sublinear response with a linearity index varying from 1 to 1.4 (max.) and finally reducing to 0.9. The TL kinetic parameters such as the activation energy (E), frequency factor (s), and order of the kinetics have been obtained by initial rise, peak shape, and glow curve deconvolution methods. The order of the kinetics for the TL peak has been found to be 2.25 for 485 K and 2 for 620 K. The dosimetric studies showed that BaB2O4:Tb is suitable for dose measurements in high radiation areas, like glove box, hot cells, gamma irradiators etc., except for low energy gammas and x-rays.

Gamma radiation induced microwave absorption properties of Ultra-thin barium titanate (BaTiO3) ceramic tiles over X-Band (8.2–12.4GHz)

We report the enhancement of microwave absorption properties in BaTiO3 ceramics induced by exposing under high energy gamma radiation at 5 kGy, 10 kGy and 15 kGy, gamma-ray doses in a properly shielded Co60 γ-radiation chamber. The tetragonality ratio (c/a) decreases with increasing gamma dose on powder samples together with the reduction of grain size from ~2 μm to ~0.5 μm. Further, the irradiated BaTiO3 powder based ceramic tiles are fabricated and electromagnetic (EM) measurements suggest increase in imaginary permittivity and loss tangent values (tanδe) at resonance frequency of ~8.8 GHz. Reflection loss (RL) plots of BT tiles showed enhancement in microwave loss at higher gamma radiation doses. As per the customized requirements, two type of extremely thin ceramic tiles are obtained viz. Resonating (RL> 40 dB at 9.6 GHz) and wide-band (RL> 8 dB over entire X-band) for their possible use for MW attenuation on different objects/platforms.

Preparation and characterisation of irradiated waste eggshells as oil adsorbent

Adsorption method had been developed by using natural organic adsorbent for the removal of oil because of its ability to bind the oil molecules into the surface of adsorbent. In this study, chicken eggshells waste was used and it undergoes irradiation process with four different amount of dose which was 0.5 kGy, 1.0 kGy, 1.5 kGy, and 2.0 kGy by using Gamma Cell Irradiator. Three equipment had been used for the characterization process which were the Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDX), and Fourier-Transform Infrared Spectroscopy (FTIR). The adsorption experiment was conducted to calculate the sorption efficiency by using different mass of samples. The result showed that irradiated chicken eggshells powder with 2.0 kGy amount of radiation dose has a best performance as oil adsorbent.

Exploring the Potentialities of Photoinduced Glycation to Steer Protein Functionalities: The Study Case of Freeze-Dried Egg White Proteins/Carbohydrates Mixtures.

The capacity of UV-C light to induce glycation and modify functional properties of systems containing freeze-dried egg white proteins and carbohydrates with increasing molecular weight (i.e., glucose, maltose, trehalose and maltodextrin) was studied. Color changes induced by light exposure were taken as typical indicators of glycation. Samples were then analyzed for selected physical (critical concentration, particle size and viscosity), chemical (ovalbumin content) and technofunctional properties (gelling temperature and foaming capacity). The presence of sugars during exposure to UV-C light promoted intense browning and decreased ovalbumin content by circa 30%. Concomitantly, up to a 3-fold increase in critical concentration of the aqueous suspensions of the irradiated protein-carbohydrate powders and changes in particle size were detected. These modifications were consistent with the development of non-enzymatic browning reactions upon UV-C light irradiation. Photoinduced glycation was associated to a decrease in viscosity, a tendency to form gel at temperature lower by up to 8 °C and a better capacity of foam stabilization. The intensity of these changes seems to be affected by the nature of the carbohydrates reacting with proteins, with longer carbohydrates able to produce systems with higher foam stability capacity.

Heavy metal release from irradiated LDPE/nanometal composite films into food simulants

• Nanometal (ZnO, Cu or Ag) embedded LDPE films were prepared and characterized. • The effect of gamma irradiation on heavy metal release from LDPE films was evaluated. • The irradiated LDPE films (with solvent contact) released more heavy metals. • Such phenomenon was attributed to the accelerated metal oxidation under irradiation. Low-density polyethylene (LDPE) films containing three types of nanometals (ZnO, Cu, or Ag) were prepared and characterized. A release experiment was carried out on the nanocomposite films subjected to three treatments: no irradiation, gamma irradiation with solvent contact (10 kGy), and gamma irradiation without solvent contact. The release of heavy metals from the nanocomposite films into three types of solvents (water, 95 % ethanol, and 3 % acetic acid) was recorded at room temperature. In general, gamma irradiation was likely to promote the release of heavy metals. The release amount of heavy metals depended on the type of nanometal and solvent. An increase in release amount of Zn and Cu was observed in 95 % ethanol and Ag in all types of solvents at the end of the experiment after the film samples were treated with gamma irradiation (with solvent contact during irradiation). The increase in heavy metal release was attributed to the accelerated surface oxidation of nanometals after irradiation, as confirmed by XPS analysis on the irradiated Ag powders.

A dual natural lithium formate/L-alanine EPR dosimeter for a mixed radiation field in a boron neutron capture therapy irradiation facility

Standard commercial L-alanine pellets and specially prepared natural lithium formate monohydrate powder samples of specific granulometry were irradiated in a 60Co gamma-ray irradiation plant and in the mixed field (thermal neutrons and gamma photons) of a boron neutron capture therapy (BNCT) experimental facility. The γ-doses applied with the 60Co source range from 0.1 to 50 kGy, while those in the BNCT facility go from ~7 Gy to 150 Gy. The thermal neutron fluences range from 1012 neutrons cm−2 to 2 1013 neutrons cm−2. The irradiation of materials promotes the creation of stable electronic defects (generally free radicals) which constitute paramagnetic centers that can be detected and quantified by electron paramagnetic resonance (EPR). After irradiation, the EPR characterization of the samples was performed by determining the EPR intensity of the spectrum relative to a reference standard constituted by Mn2+ impurities diluted into a MgO single crystal. As expected, L-alanine has revealed to be largely insensitive to thermal neutrons fluence in the investigated range. On the contrary, it is shown that the EPR intensity of irradiated natural lithium formate monohydrate powders is clearly sensitive to thermal neutrons and has a linear dependence with the γ-dose. We propose a dual dosimeter by combining L-alanine pellets and formate powders that would allow to determine the γ-dose and thermal neutron fluence in a selected position of the BNCT irradiation facility. Moreover, we demonstrate that the 6Li enrichment that has been proposed in the literature to enhance the performance of lithium-based EPR dosimeters is not crucial in our case. Instead, the natural isotopic abundance of lithium is large enough to obtain a satisfactory sensibility to thermal neutrons in our BNCT facility for fluencies >1012 neutrons cm−2.

Long-Term Photostability in Terephthalate Metal-Organic Frameworks.

Prolonged (weeks) UV/Vis irradiation under Ar of UiO-66(Zr), UiO66 Zr-NO2 , MIL101 Fe, MIL125 Ti-NH2 , MIL101 Cr and MIL101 Cr(Pt) shows that these MOFs undergo photodecarboxylation of benzenedicarboxylate (BDC) linker in a significant percentage depending on the structure and composition of the material. Routine characterization techniques such as XRD, UV/Vis spectroscopy and TGA fail to detect changes in the material, although porosity and surface area change upon irradiation of powders. In contrast to BCD-containing MOFs, zeolitic imidazolate ZIF-8 does not evolve CO2 or any other gas upon irradiation.

Long‐Term Photostability in Terephthalate Metal–Organic Frameworks

AbstractProlonged (weeks) UV/Vis irradiation under Ar of UiO‐66(Zr), UiO66 Zr‐NO2, MIL101 Fe, MIL125 Ti‐NH2, MIL101 Cr and MIL101 Cr(Pt) shows that these MOFs undergo photodecarboxylation of benzenedicarboxylate (BDC) linker in a significant percentage depending on the structure and composition of the material. Routine characterization techniques such as XRD, UV/Vis spectroscopy and TGA fail to detect changes in the material, although porosity and surface area change upon irradiation of powders. In contrast to BCD‐containing MOFs, zeolitic imidazolate ZIF‐8 does not evolve CO2 or any other gas upon irradiation.