Unirradiated Ones Research Articles

Optical properties of Makrofol under various alpha fluences

The optical properties of Makrofol samples are investigated under various fluences of alpha exposure (2 MeV at 5×102, 103, 5×103, 104 , 5×104, 105, 5×105 and 106 alphas.cm2 alongside the unirradiated ones (pristine). Several analyses, including UV–visible, diffused reflectance spectroscopy (DRS), photoluminescence (PL), Fourier transform infrared/attenuated total reflectance (FTIR-ATR), X-ray photoelectron spectroscopy (XPS) and sessile drop technique, are carried out to reveal the subsequent variations in the optical features of the irradiated polymer foils. The optical transmittance of the irradiated samples notably increases against the pristine ones, while it undergoes a+ plateau over various fluences. Additionally, the scattering events are more prominent in pristine samples over UV (240–400 nm) and IR (900–1040 nm) compared to the irradiated ones. While there are negligible physical alterations on the polymer surface, the photoluminescence emission gradually decreases with increasing alpha fluences in the irradiated samples mainly due to the reduction in the population of the aromatic rings. The latter is also verified by means of the surface chemical analyses such as XPS, FTIR-ATR and sessile drop/contact angle measurements. XPS reveals that the alpha particles give rise to the successive scissions of C–C and CO bonds and the consequent recombination events in the form of C–O bonds, evidenced by the changes in their abundance percentages. Concurrently, the surface hydrophilicity initially elevates up to a certain fluence and then reduces at higher fluences, indicating a couple of competitive mechanisms are involved in the context of the interactions of the alpha particles with the Makrofol polycarbonate (PC).

Utilization of agro waste activated carbons as carbon black replacement in electron beam irradiated styrene butadiene rubber composites

Purpose This study aims to prepare activated carbon (AC) and activated biochar (BC) from sugarcane bagasse (SCB) can be used as carbon black (CB) replacement for styrene butadiene rubber (SBR) composites cured by electron beam (EB) radiation. Design/methodology/approach This study is carried out to investigate the effect of partial replacement of CB (as traditional filler) by AC or BC prepared from low-cost agricultural wastes (SCB) to improve the properties of SBR rubber cured by EB radiation (doses from 25 to 150 kGy). Findings The results indicated that the addition of AC or BC leads to improve the physical and mechanical properties of SBR with increasing irradiation dose [especially at concentration of 10 parts per hundred part of rubber (phr) from BC]. Also in this study, this paper examines how exposure of SBR rubber composites to ultraviolet (UV) radiation changes the mechanical properties for these composites, to do that, the specimens were examined before and after they were exposed to UV radiation for 300 h. The results showed that, the irradiated SBR composites, UV exposure, exhibit better retention in mechanical properties as compared with unirradiated ones, and the samples loaded with CB hybrid with ACs had an increased value of tensile strength (TS) retention as compared with blank sample. Originality/value The importance of this study is that, the production of AC from SCB offers a huge opportunity to overcome the problem of the disposal of SCB.

Physicochemical and antimicrobial characteristics of polypropylene-based nanocomposite containing SiO2-Ag nanoparticles prepared by gamma irradiation

This article evaluates the physicochemical and antimicrobial properties when silver-coated silica (SiO2-Ag) nanoparticles as active nanofiller are incorporated into the polypropylene (PP) thermoplastic matrix. The silica (SiO2) nanoparticles were prepared by precipitation method using sodium silicate. After that, silver-coated silica (SiO2-Ag) nanoparticles were synthesized by gamma radiation technique. X-ray diffraction (XRD), Infrared spectroscopy analysis (FTIR) and Transmission electron microscopy (TEM) analysis clarified the formation of SiO2-Ag nanoparticles. SiO2-Ag nanoparticles has a particle size with an average of 70 nm. The melt mixing procedure operated to fabricate PP thermoplastic nanocomposites with various ratios of 1.0, 2.0, and 3.0 part per hundred resin (phr) of the SiO2-Ag nanoparticles. To examine the effect of ionizing radiation on the prepared PP/SiO2-Ag nanocomposites, the samples were exposed to 20 kGy of gamma-irradiation. FTIR, XRD, mechanical analysis, thermogravimetric analysis (TGA), and scanning electron microscope (SEM) were utilized to characterize the physico-chemical alterations of the PP when loaded with SiO2-Ag nanoparticles. It is found that PP/1.0 phr SiO2-Ag nanocomposite revealed superior physico-chemical characteristics than the other two components. The irradiated specimens revealed superior tensile strength (TS) and elastic modulus (EM) over unirradiated ones, whereas inverse effects were predominant in case elongation at break (E%). Tmax of the native PP increased from 335°C to nearly 370°C of PP/1.0 phr SiO2-Ag nanocomposite. It is established that the fabricated PP/SiO2-Ag nanocomposites exhibited potent antimicrobial activity and can be a good candidate for food packaging applications.

Morphological, structural and mechanical characteristics of laser-treated pure lead

Abstract The impact of high-intensity visible radiation on the morphological, structural, and mechanical characteristics of pure lead has been examined via the irradiation of a continuous-wave diode laser on its samples. SEM and X-ray diffractometers were used to analyze the surface and structural morphology of the irradiated samples. The appearance of the burning effects, redeposition of material, and melt pools were checked after the irradiations in the SEM analysis. On the other hand, through the diffractometric X-ray analysis, the targeted sample’s d-spacing, grain size, and dislocation line density were resolved. To understand the mechanical characteristics of lead, the change in hardness of the materials was tested as a function of exposure duration using the micro-Vickers hardness tester, and the resulting outcomes were compared with those of unirradiated ones. The hardness of lead is enhanced as the exposure time increases, and this is accompanied by a continuous reduction of the grain size.

Studies on the effects of highenergy electron beam irradiation on the Mechanical properties of Magnesium hydroxide filled HDPE/Mg(OH)2/TCA-27 composites

The effect of irradiation electron beam at dose of 150 kGy,on the mechanical properties of
 high density polyethylene (HDPE) mixed with various amounts of magnesium hydroxide (Mg(OH)2) composites as filler have been studied here. It has been found that the highenergy electron beam irradiation has much effect on the mechanical properties of the
 HDPE/Mg(OH)2/TCA-27 composites. The tensile strength and elastic modulus are increased greater than the unirradiated ones. Meanwhile, the increasing content of the Mg(OH)2 in composites. The structure of the SEM of the unirradiated HDPE/ Mg(OH)2/TCA-27 shows poorly mechanical properties of compositeswhich are compared to irradiated ones. The Comparison of properties of composites filled with irradiated and unirradiated Magnesium hydroxide establishes than irradiated of Magnesium hydroxide which imparts better reinforcing properties than unirradiated filler of composites. The properties under consideration are tensile strength, (%) elongation at break, elastic modulus, hardness . Tensile strength isimproved by 6.67% , elastic modulus is improved by 42.86%, while hardness is improved by 0.85%, at ( 0.37 ) volume fraction .

Electron spin resonance (ESR) spectroscopy study of gamma-irradiated dried white mulberry (Morus Alba L.) fruits

Two different groups of dried fruits of white mulberry (Morus Alba L.) sold in Turkish markets were investigated by the X-band ESR spectroscopy technique for irradiation detection purposes. No resonance signals were detected in the ESR spectra of the un-irradiated samples. After irradiation, identical multi-line resonance signals were induced in the ESR spectra of both types of samples, except for the intensities. At doses of 2 and 10 kGy, the long-term stabilities of the radiation-induced radicals at room temperature were investigated over a storage period of about 100 days. The results obtained show that the ESR technique can be used to distinguish irradiated white mulberry fruits from un-irradiated ones.

Total Ionizing Dose Effects on Long-Term Data Retention Characteristics of Commercial 3-D NAND Memories

This article evaluates the data retention characteristics of irradiated multilevel-cell (MLC) 3-D NAND flash memories. We irradiated the memory chips by a Co-60 gamma-ray source for up to 50 krad(Si) and then wrote a random data pattern on the irradiated chips to find their retention characteristics. The experimental results show that the data retention property of the irradiated chips is significantly degraded when compared to the un-irradiated ones. We evaluated two independent strategies to improve the data retention characteristics of the irradiated chips. The first method involves high-temperature annealing of the irradiated chips, while the second method suggests preprogramming the memory modules before deploying them into radiation-prone environments.

Impact of gamma radiation and multi-walled carbon nanotubes on the mechanical and acoustical properties of reinforced sisal fiber/polyester resin composites

In this work, the effect of exposure to 5 kGy of Gamma radiation and the addition of Multi-walled carbon nanotubes (MWCNT) in different concentration 0, 0.2, 0.4 and 0.6 wt% to sisal fiber/unsaturated polyester resin (SF-UP) composites (40/60) on the mechanical and acoustical properties was investigated. An enhancement in the mechanical properties was achieved by addition MWCNT up to 0.4%, and then decreased at 0.6%. Also, irradiation of the composite manifested an enhancement in the mechanical properties more than unirradiated ones. The tensile strength and flexural strength of irradiated SF-UP composite which contains 0.4% MWCNT were higher than unirradiated SF-UP composite which contains 0% MWCNT by 73.2 and 91.9%, respectively. The addition of MWCNT and exposure to 5 kGy of gamma radiation increased both the storage modulus and the Tg while the damping factor (tan δ) decreased. Increasing the MWCNT % enhanced the sound absorption at the higher frequencies (0.6% MWCNT (unirradiated)∼0.9 within 5000–6300 Hz), while the irradiation shifted the highest absorption toward lower frequencies (0.6% MWCNT (irradiated)∼0.63 within 2500–3150 Hz). The produced composite displayed appreciable mechanical and acoustical properties which makes it as a new partner for many advanced industrial applications.

Comparative impact of gamma radiation on reinforced nitrile rubber with graphite and agro waste activated carbons

Abstract In this article, graphite fine powder and two types of activated carbon (AC) namely based-on waste corn and sugarcane bagasse were implemented as reinforcers for the nitrile rubber (NBR). Both types of AC were prepared through a low-temperature chemical carbonization treatment. Each type of these fillers, at 5, 10, and 15 wt%, was mixed with NBR on a rubber mill and pressed under heat to develop sheets to be gamma irradiated at 100 kGy. Filler characterization using Fourier Transform Infrared spectrophotometer (FTIR) spectroscopy and scanning electron microscopy (SEM) were discussed. X-ray diffraction (XRD) proved that graphite has a crystalline structure but corn and bagasse ACs have amorphous nature. Furthermore, dynamic light scattering (DLS) analysis was used to determine the particle size of the studied fillers. In addition, mechanical properties, XRD, thermal stability, and SEM of the prepared unirradiated or irradiated NBR‒composites were investigated. The physicomechanical features of the NBR matrix could be enhanced by the presence of reinforcing fillers, even at relatively low filler loading. The composites filled with graphite showed superior mechanical parameters and also have the highest thermal stability as indicated by their high-temperature mass loss (Tm). Generally, irradiated samples expressed grander properties than unirradiated ones as a result of the radiation-induced crosslinking structures.

Effects of gamma radiation and Bacillus thuringiensis on F1 progeny of Cydia pomonella

Summary The codling moth [Cydia pomonella L. (Lepidoptera: Tortricidae)] is the main pest in most apple orchards in Syria. It causes billions of dollars in loss of fruit crops every year. The present work examined the effects of gamma radiation and Bacillus thuringiensis (BT) on F1 progeny of C. pomonella. The experimental design was based on two factors, namely F1 offspring produced by males irradiated at a dose of 150 Gy, and artificial diet of BT-treated larvae. The first offspring of unirradiated and irradiated C. pomonella males, F1, were from parents treated with a commercial formulation of Bacillus thuringiensis BT (Dipel® 2X). F1 progeny of unirradiated was significantly less susceptible to BT than that of irradiated parents. The results showed high mortality in F1 progeny of C. pomonella when gamma radiation and BT were applied together. The LC50 in F1 progeny was 2.5 ppm for irradiated parents, while it was 13 ppm for unirradiated ones. A significant reduction in the fecundity and egg hatchability of F1 progeny of irradiated parents compared to unirradiated ones was observed. This study demonstrated that for F1 progeny the combination between Inherited Sterility Technique and BT can be useful to achieve an integrated pest management program of codling moth.

Influence of Ultraviolet Radiation on Mechanical Properties of a Photoinitiator Compounded High Vinyl Styrene-Butadiene-Styrene Block Copolymer.

Ultraviolet curing of elastomers is a special curing technique that has gained importance over the conventional chemical crosslinking method, because the former process is faster, and thus, time-saving. Usually, a suitable photoinitiator is required to initiate the process. Ultraviolet radiation of required frequency and intensity excites the photoinitiator which abstracts labile hydrogen atoms from the polymer with the generation of free radicals. These radicals result in crosslinking of elastomers via radical–radical coupling. In the process, some photodegradation may also take place. In the present work, a high vinyl (~50%) styrene–butadiene–styrene (SBS) block copolymer which is a thermoplastic elastomer was used as the base polymer. An attempt was made to see the effect of ultraviolet radiation on the mechanical properties of the block copolymer. The process variables were time of exposure and photoinitiator concentration. Mechanical properties like tensile strength, elongation at break, modulus at different elongations and hardness of the irradiated samples were studied and compared with those of unirradiated ones. In this S-B-S block copolymer, a relatively low exposure time and low photoinitiator concentration were effective in obtaining optimized mechanical properties. Infrared spectroscopy, contact angle and scanning electron microscopy were used to characterize the results obtained from mechanical measurements.

Electron beam irradiation induced changes in local structure of simulated waste bearing sodium borosilicate glasses

Time differential perturbed angular correlation (TDPAC) and Extended X-ray absorption fine structure (EXAFS) studies have been carried out on electron beam (EB) irradiated sodium borosilicate (NBS) and simulated waste oxide loaded sodium borosilicate (SNBS) glasses with a view to investigate the effect of self β-irradiation in vitrified high level waste. NBS and SNBS glasses were synthesized and doped with 1.5% HfO2. For TDPAC studies the glasses were doped with 181Hf probe, while for EXAFS studies measurements were carried out at and around Hf LIII edge. TDPAC and EXAFS acquisition were performed before and after electron beam irradiation doses up to 10 MGy for both NBS and SNBS glasses. Fourier transforms of the TDPAC spectra show broad frequency distribution reminiscent of the disordered glass matrix, with increase in hyperfine interaction frequency in irradiated glasses with respect to unirradiated ones as well as with increasing EB dose. On the other hand, the width of the frequency distribution was found to decrease with EB dose. No change in asymmetry of the electric field gradient was observed in irradiated glasses with respect to unirradiated ones. These observations indicate that while there is no indication of appearance of micro-crystallinity in the glasses up to EB dose of 10 MGy, local structural changes around Hf do take place with EB irradiation in both the glasses. No change in metric parameters (Hf-O bond distance and coordination number of Hf) was observed from EXAFS measurements on both NBS and SNBS glasses up to EB dose of 10 MGy.

Effect of gamma irradiation and subsequent cold storage on the development and predatory potential of seven spotted ladybird beetle Coccinella septempunctata Linnaeus (Coleoptera; Coccinellidae) larvae

Seven spot ladybird beetle, (Coccinella septempunctata) is a widely distributed natural enemy of soft-bodied insect pests especially aphids worldwide. Both the adult and larvae of this coccinellid beetle are voracious feeders and serve as a commercially available biological control agent around the globe. Different techniques are adopted to enhance the mass rearing and storage of this natural enemy by taking advantage of its natural ability to withstand under extremely low temperatures and entering diapause under unfavorable low temperature conditions. The key objective of this study was to develop a cost effective technique for enhancing the storage life and predatory potential of the larvae of C. septempunctata through cold storage in conjunction with the use of nuclear techniques, gamma radiations. Results showed that the host eating potential of larvae was enhanced as the cold storage duration was increased. Gamma irradiation further enhanced the feeding potential of larvae that were kept under cold storage. Different irradiation doses also affected the development time of C. septempuntata larvae significantly. Without cold storage, the lower radiation doses (10 and 25 GY) prolonged the developmental time as compared to un-irradiated larvae. Furthermore, the higher dose of radiation (50GY) increased the developmental time after removal from cold storage. This study first time paves the way to use radiation in conjunction with cold storage as an effective technique in implementation of different biological control approaches as a part of any IPM programs

Enhancement of Luminescence Behaviour of Colloidal ZnO Quantum Dots Coated with SiO2 Irradiated by Ni+7 Ion

ZnO quantum dots of average size 10 nm are embedded in a matrix (polyvinyl alcohol (PVA)) following chemical route. They are irradiated by 100 MeV Ni7+ ion beam with fluences 1 × 1011, 3 × 1011, 1 × 1012 and 3 × 1012 ions/cm2. The optical absorption edge of irradiated quantum dots reveal negligible red shift with an increase in fluences with respect to that of unirradiated (virgin) ones. This fact clearly indicates no significant change in particle diameter under ion irradiation and is confirmed by high resolution transmission electron microscopy (TEM). AFM study also reveals the r.m.s surface roughness of the particles. It has also been observed that irradiated quantum dots produce similar type of photo luminescence and electroluminescence like virgin samples but the emission intensity increases remarkably after irradiation due to creation of large numbers oxygen vacancies by the ion beam.

Investigation on the radiolytic stability of polybenzimidazole-based polymeric resins for the recovery of lanthanides, actinides, palladium from aqueous medium

Radiolytic stability of polymeric resins is an important aspects in nuclear materials processing. The different dosage of gamma radiation was subjected to meta-polybenzimidazole (m-PBI), para-polybenzimidazole (p-PBI) and pyridine-m-PBI based polymeric resins, which was taken for the present radiolytic stability investigation. Irradiated polymers were characterized by FT-IR, SEM and TGA analysis. Extraction of U(IV) and Pd(II) as a function of nitric acid concentration using 50, 100 and 150 kGy gamma irradiated polymeric resins was carried out and static capacity was also investigated for the gamma irradiated polymeric resins and compared with their unirradiated ones. In addition, the extraction behaviour of radionuclides, namely, plutonium, americium and europium as a function of HNO3 concentration utilizing both unirradiated and 150 kGy gamma irradiated polymeric resins was studied for the first time. Results indicated that FT-IR spectra of both unirradiated and 150 kGy irradiated resins are similar. TGA analysis revealed 50% and 20% weight loss for pyridine-m-PBI, m-PBI, respectively. The distribution ratio values decreases with increase in gamma irradiation. The uranium and palladium static capacities were found to be 30 and 182 mg/g resin, respectively. The overall results indicated that p-PBI resin has higher extraction efficiency and exhibits better radiation resistant behaviour as compared to pyridine-m-PBI and m-PBI.

Effect of carbon ion irradiation on the structural, mechanical and electrical properties of polycrystalline tungsten

To investigate the effects of carbon ion irradiation on the structural, mechanical and electrical properties of polycrystalline tungsten, four tungsten specimens were irradiated by 5 MeV carbon ions (C+2) at various doses ranging from 0.5 × 1015 to 3 × 1015 ions cm−2 for different exposure times. X-ray diffraction analysis confirmed the slight structural modification by increase or decrease in diffracted peak intensity, crystallite size and lattice strains upon ion irradiation. In addition, there was no substantial evidence of new phase/s in α-tungsten at high energy ions. Initially, at a lower dose rate of 0.5 × 1015 ions cm−2, the average surface hardness and electrical resistivity were found to decrease due to the increase of crystallite size. However, elevated dosed (≥1 × 1015 ions cm−2) specimens show a significant increase in their surface hardness and electrical resistivity in comparison to un-irradiated ones. The variation of surface hardness and electrical resistivity of irradiated tungsten is well correlated with crystallographic modifications, which is ascribed to the generation, recombination, augmentation, and annihilation of ion-induced defects.

Effects of gamma radiation on the impact strength of polypropylene (PP)/high density polyethylene (HDPE) blends

Abstract Polypropylene (PP) blends with the other polymer, like polyethylene (PE), is normally used as for improving PP impact strength. In this paper, we wanted to improve the PP/high density polyethylene (HDPE) impact strength by increasing the compatibility of PP/HDPE with gamma irradiation process that the un-irradiated ones were also used for comparison. It was obvious that the impact strength increased when the HDPE (10 phr) was added into the PP matrix, compared with neat PP. Meanwhile, the irradiated ones had higher impact strength than that of un-irradiated PP/HDPE blends. This was contributed to the finer compatibility in γ-irradiated PP/HDPE blends, seen from the SEM. Furthermore, the FTIR data also confirmed that the 1,4-butanediol diacrylate (BDDA) was grafted on the backbone of PP/HDPE blends by γ radiation. It speculated that this correlated with the compatibilization improvement in γ-irradiated PP/HDPE blends. Finally, the possible mechanism after γ-irradiation was also proposed in this paper.

Irradiated rubber composite with nano and micro fillers for mining rock application

Abstract In this work, nanosilica and micro carbon black (CB) as a fillers were used to improve the properties of styrene butadiene rubber/natural rubber blends (SBR/NR) crosslinked by γ radiation. Nanosilica was prepared from silica sand and used as eco-friendly material. These composites were characterized by field emission scanning electron microscopy (FESEM) and the measurements of the physic-mechanical and thermal properties were measured. Field emission scanning electron microscopy showed that the composites reinforced by nanosilica and the measurements of the CB are uniformly dispersed in the blends matrix. The results showed that the physico-mechanical and thermal properties were improved indicating a good interaction between the fillers and rubber matrix. The volume fraction measurements confirmed the formation of crosslinking network structure. Meanwhile, the reinforcement of SBR/NR blend loaded with nanosilica showed improved mechanical than blend loaded with both the nanosilica/carbon black and the CB alone. The highest enhancement was obtained for the three fillers by using a concentration of 35 phr at a dose of 150 kGy of γ-irradiation. Thermogravimetric analysis (TGA) indicated that the thermal stability of SBR/NR blend reinforced by nanosilica is higher than those blends reinforced with combined filler the silica. It was also found that the irradiated SBR/NR nanocomposites were more stable than the un-irradiated ones.

The mechanical, thermal and morphological properties of γ-irradiated PLA/TAIC and PLA/OvPOSS

In the present work, various blend ratios of poly (lactic acid) (PLA), triallylisocyanurate (TAIC) and octavinyl-POSS (OvPOSS) were prepared by melt compounding in an Xplore microcompounder and molded by an Xplore microinjection molding device. POSS is a new generation organic/inorganic hybrid nanoparticle having possibility to improve the performance of polymers without sacrificing mechanical and thermal properties. TAIC and OvPOSS were used as crosslinking agents. After the compounding process, PLA, PLA/TAIC and PLA/OvPOSS composites were exposed to a gamma irradiation at various adsorbed doses ranging from 0 to 100 kGy. The properties of neat PLA, PLA/TAIC and PLA/OvPOSS composites were investigated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) and tensile testing. Results showed that both chain scission reactions and formation of network structure occurred simultaneously after gamma irradiation. The highest gel formation was obtained from PLA composites including 3 wt% OvPOSS at the dose of 100 kGy. DSC results indicated that a sharp decrease in the degree of crystallinity (Xc%) of PLA in the presence of TAIC and OvPOSS was obtained after gamma irradiation process. All irradiated composites exhibited lower elongation at break and higher E-Modulus values at any irradiation doses. TGA results showed that irradiated samples were more thermally stable than the unirradiated ones. Moreover, the heat deflection temperature (HDT) of PLA in the presence of TAIC and OvPOSS was found higher than that of neat PLA. Brittle surface morphology of composites after gamma irradiation process was obtained from SEM analysis.

Enhanced Efficiency in Swift Heavy Ion Irradiated CdS Quantum Dots Sensitized Solar Cell

The influence of high energy ion beam [swift heavy ion (SHI)] on CdS quantum dots that are used as a sensitizer in a solar cell is studied in this letter. A 100-MeV copper ion beam is selected for irradiation experiment with doses of $1\times 10^{11}$ and $3\times 10^{11}$ ions/cm2. With an increase in the dose, the optical absorption edge of irradiated quantum dots reveals a little red shift with respect to that of unirradiated (pristine) ones. The irradiated quantum dots are introduced as a sensitizer on a ZnO photoelectrode solar cell. An increase in the current density is observed for irradiated samples at a lower dose, while at a higher dose, the current density decreases. In addition, the other parameters, like open circuit voltage, fill factor, and photo-conversion efficiency, are also reported for the SHI-irradiated quantum dot sensitized solar cell.