This study presents a novel use of an electron beam irradiation system for the gas phase synthesis of nanoparticles, and demonstrates that SiO2 nanoparticles can be synthesized in ambient conditions. The formation of SiO2 nanoparticles is confirmed by the vibrational modes shown in FT-IR spectra, and the binding energy of Si 2p in the X-ray photoelectron spectrum. In this work, nanoparticles with average diameters of 210 nm and 73 nm were produced. The average particle size was controlled by adjusting the residence time of the precursor vapor.

The atmospheric carbon dioxide levels are steadily increasing which requires urgent action for its capture, storage, and utilization. To mitigate CO2 effectively and economically research has been focused to improving CO2 capture and storage technologies. Conventional technologies possess a number of shortcomings including space limitations, high energy consumption, high cost as well as solvent handling problems. The ability of solid sorbents and membranes in CO2 separation provoked researchers to develop advanced sorbents and membranes mainly composed of polymers. In this preview important role of radiation technology in developing such materials has been discussed with special emphasis on the use of metal-organic frameworks as the state-of-the-art fillers in the preparation of mixed matrix membranes (MMMs) for capturing CO2. The use of ionizing radiation in converting CO2 into useful value-added products is explored in terms of radiation-induced modification of catalysts used in thermal, electro- and photo-induced reduction of CO2. Successful examples of radiation chemistry applied to the development of materials and processes in mitigating carbon footprint are discussed with a future outlook.

In the era of circular economies, municipal wastewater treatment plants (WWTPs) are viewed as resource recovery facilities. At the very minimum, the targeted resources are water, biogas, and phosphorus. However, municipal wastewater streams (sludge and effl uent) need to be adequately treated to eliminate the potential for the transmission of microbial pathogens including protozoa, bacteria, and viruses. This paper presents the results from a study demonstrating the use of electron beam technology for sludge hygenization and enhanced methane (biogas) production using municipal wastewater samples. Cogeneration of heat for fertilizer drying and granulation and electricity for powering the electron beam system are also demonstrated.

Radiation processing technologies aimed at ensuring the safety of gaseous and liquid effluents discharged to the environment have been developed. It has been demonstrated that radiation processing-based technologies for flue gas treatment (SOx and NOx removal) at coal and oil fired power plants, wastewater purification, and sludge hygienization and biohazards control can be effectively deployed to mitigate environmental degradation. Byproducts of flue gas purification and sludge hygenization are high value fertilizer, which is a great contribution of radiation technology to circular economy scheme implementation. Emerging technologies are now focused to encourage ballast water and ship diesel off-gases treatment to follow recent standards introduced by the International Maritime Organization. Therefore, all these technologies are an important supplement of nuclear technology in preserving a clean environment for our global future.

Worldwide, there are over 1700 electron beam (EB) units in commercial use, providing an estimated added value to numerous products, amounting to 100 billion USD or more. High-current electron accelerators are used in diverse industries to enhance the physical and chemical properties of materials and to reduce undesirable contaminants such as pathogens, toxic byproducts, or emissions. Over the past few decades, EB technologies have been developed aimed at ensuring the safety of gaseous and liquid effluents discharged to the environment. It has been demonstrated that EB technologies for flue gas treatment (SO x and NO x removal), wastewater purification, and sludge hygienization can be effectively deployed to mitigate environmental degradation. Recently, extensive work has been carried out on the use of EB for environmental remediation, which also includes the removal of emerging contaminants such as VOCs, endocrine disrupting chemicals (EDCs), and potential EDCs.

Polychlorinated biphenyls are toxic compounds which have accumulated in river sediments in Eastern Slovakia. Bioaccumulation could cause even cancer. Radiation degradation with electrons is new and perspective method to dechlorinate PCBs in sediment matrix. We tested the influence of two difference chemical pretreatments and electron irradiation on PCB contaminated sediments.

Endocrine disrupting chemicals (EDCs) and potential EDCs are mostly man-made, found in various materials such as pesticides, additives or contaminants in food, and personal care products. EDCs have been suspected to be associated with altered reproductive function in males and females increased incidence of breast cancer, abnormal growth patterns and neuro-developmental delays in children and changes in immune function. A number of processes were investigated regarding their potential for removing of endocrine disrupters. Those processes are ferric chloride coagulation, powdered activated carbon, magnetic ion exchange combined with microfiltration or ultrafiltration, as well as nanofiltration, and reverse osmosis. They show some good removal of EDCs in aqueous solution, but do not show good efficiency when EDCs are in sludge. High energy ionizing radiation has the ability to remove the EDCs with a very high degree of reliability and in a clean and efficient manner. The ionizing radiation interacts with EDCs both directly and indirectly. Direct interaction takes place with EDCs, and the structure of EDCs is destroyed or changed. During indirect interaction, radiolysis products of water result in the formation of highly reactive intermediates which then react with the target molecules, culminating in structural changes. For confirmation of radiation reduction of EDCs in industrial sludge, a pilot scale experiment up to 50 kGy of electron beam was conducted with samples from the textile dyeing industries. The experimental result showed over a 90% reduction of nonylphenol (NP) at absorbed doses of around 10 kGy.

The pilot scale electron beam flue gas treatment (EBFGT) plant was constructed at Saudi Aramco's Refinery in Jiddah, Saudi Arabia. The plant was designed to treat 2000Nm3/h of flue gas emitted from a heavy fuel oil fired boiler. A unique mobile electron accelerator unit (600keV, 20kW) made by EB TECH Co., Ltd., Korea was used as a beam source. The pilot plant operation proved the high potential of the technology for simultaneous control of sulfur dioxide (SO2) and nitrogen oxides (NOx) emissions. The obtained removal efficiencies reached 98.5% for SO2 and 83.1% for NOx. Two types of byproduct collection devices – cartridge bag filter and electrostatic precipitator – were tested. The obtained byproduct was a high quality fertilizer that can be used directly or as a substrate for NPK blends manufacturing. The soluble part of the byproduct was almost pure ammonium sulfate (98% to 99%) with some amount of ammonium nitrate. The content of heavy metals in the byproduct was very low and lower than the allowed standards by two orders of magnitude. The results of the research are the basis for the design of a full industrial scale EBFGT plant for treatment of flue gas from heavy fuel oil combustion.

Due to the necessity of pilot scale test facility for continuous treatment of wastewater and gases on site, a mobile electron beam irradiation system mounted on a trailer has developed. This mobile electron beam irradiation system is designed for the individual field application with self-shielded structure of steel plate and lead block which will satisfy the required safety figures of International Commission on Radiological Protection (ICRP). Shielding of a mobile electron accelerator of 0.7MeV, 30mA has been designed and examined by Monte Carlo technique. Based on a 3-D model of electron accelerator shielding which is designed with steel and lead shield, radiation leakage was examined using the Monte Carlo N-Particle Transport (MCNP) Code. Simulations with two different versions (version 4c2 and version 5) of MCNP code showed agreements within statistical uncertainties, and the highest leakage expected is 5.5061×10−01 (1±0.0454) μSv/h, which is far below the tolerable radiation dose limit for occupational workers. This unit could treat up to 500m3 of liquid waste per day at 2kGy or 10,000Nm3 of gases per hour at 15kGy.

The melon and cotton aphid, Aphis gossypii, is a polyphagous insect pest. This study compared the development, reproduction, DNA damage, recovery, and gene expression in imidacloprid-resistant (IMI-R) and -susceptible (S) strains of A. gossypii by electron beam irradiation. When 1st instar nymphs were irradiated with 100 Gy, the fecundity (nymphs of F1 generation) of the resultant adults were completely inhibited. When adults were irradiated with 200 Gy, the number of total 1st instar nymphs produced per adult was 3.0±1.7 and 1.9±1.4 in the S and IMI-R strains, respectively, but adult development was completely suppressed. However, electron beam irradiation did not affect adult longevity in either the S or IMI-R strain. There was no statistically significant difference between the effect of irradiation on the S and IMI-R strains. Therefore, electron beam irradiation at 200 Gy could be used as a phytosanitary irradiation treatment for both S and IMI-R strains of A. gossypii. The DNA damage caused by electron beam irradiation was evaluated by an alkaline comet assay. Exposure to an electron beam (50 Gy) induced DNA damage that was repaired to a similar level as the untreated control group (0 Gy) over time. However, at more than 100 Gy, the DNA damage was not completely repaired. The expression of P450, HSP70, cuticle protein, and elongation factor genes were higher in the IMI-R strain than in the S strain.

PURPOSE:A beam-blocker composed of multiple strips is a useful gadget for scatter correction and/or for dose reduction in cone-beam CT (CBCT). However, the use of such a beam-blocker would yield cone-beam data that can be challenging for accurate image reconstruction from a single scan in the filtered-backprojection framework. The focus of the work was to develop an analytic image reconstruction method for CBCT that can be directly applied to partially blocked cone-beam data in conjunction with the scatter correction.METHODS:The authors developed a rebinned backprojection-filteration (BPF) algorithm for reconstructing images from the partially blocked cone-beam data in a circular scan. The authors also proposed a beam-blocking geometry considering data redundancy such that an efficient scatter estimate can be acquired and sufficient data for BPF image reconstruction can be secured at the same time from a single scan without using any blocker motion. Additionally, scatter correction method and noise reduction scheme have been developed. The authors have performed both simulation and experimental studies to validate the rebinned BPF algorithm for image reconstruction from partially blocked cone-beam data. Quantitative evaluations of the reconstructed image quality were performed in the experimental studies.RESULTS:The simulation study revealed that the developed reconstruction algorithm successfully reconstructs the images from the partial cone-beam data. In the experimental study, the proposed method effectively corrected for the scatter in each projection and reconstructed scatter-corrected images from a single scan. Reduction of cupping artifacts and an enhancement of the image contrast have been demonstrated. The image contrast has increased by a factor of about 2, and the image accuracy in terms of root-mean-square-error with respect to the fan-beam CT image has increased by more than 30%.CONCLUSIONS:The authors have successfully demonstrated that the proposed scanning method and image reconstruction algorithm can effectively estimate the scatter in cone-beam projections and produce tomographic images of nearly scatter-free quality. The authors believe that the proposed method would provide a fast and efficient CBCT scanning option to various applications particularly including head-and-neck scan.

The image of the current non-destructive testing system using a high energy accelerator is limited to conventional two-dimensional metaphysical information. Requirements for the present manufacturing industry are growing rapidly and include quantitative measurements, high-density component model extraction, reverse process development and precision inspection to meet the needs for the verification of manufactured goods. Therefore, industrial three-dimensional high-penetration tomography has emerged as the most promising method. In this study, in order to evaluate the applicability of a MeV-level high-energy accelerator, we developed a three-dimensional tomography system using a 450 kV X-ray generator. Evaluation of the three-dimensional tomography image is based on measurements of the penetration and the image resolution for high-energy X-rays.

This study determined hydrocarbons induced by gamma and electron beam irradiation of ground beef. The samples were irradiated with 0, 2.5, 5, 7.5, 10, 15, and 20 kGy dosages of gamma-rays and an electron beam. The lipid contents were extracted by hexane and the induced hydrocarbons were separated and identified by gas chromatography–mass spectrometry. The analytical method was validated by characterization of detection limits, linearity, precision, and recovery; satisfactory results were obtained in all cases. The major hydrocarbons detected in irradiated ground beef samples were pentadecane and 1-tetradecene from palmitic acid, heptadecane, and 1-hexadecene from stearic acid, and 8-heptadecene and 1,7-hexadecadiene from oleic acid. The induced hydrocarbons were detected at irradiation levels above 2.5 kGy but not in the absence of irradiation. The induced hydrocarbons showed an increase with radiation dosage, but the concentration was slightly higher for gamma rays than for the electron beam. The 1-tetradecene, 8-heptadecene, and 1,7-hexadecadiene were detected as the major hydrocarbons and showed good linearity with irradiation level. It was concluded that these major hydrocarbons are suitable markers to distinguish irradiated and unirradiated ground beef.

Seed sprouts are susceptible to microbial contaminations, which might cause foodborne illnesses. In this study, gamma- and electron beam (e-beam)-irradiated (0-3kGy) Chinese cabbage seeds (Brassica rapa ssp. Pekinensis) and their sprouts were investigated for the physicochemical, functional and microbiological qualities during storage. The irradiated seeds and their sprouts showed better overall microbial quality compared with nonirradiated samples; however, their hygienic quality profiles were same during storage of sprouts. The contents of ascorbic acid, carotenoid, chlorophyll and total phenolics of the seeds increased during germination but negligible changes were found during postharvest storage. Gamma irradiation and e-beam had similar effects on the physicochemical quality of Chinese cabbage seed sprouts with few exceptions (low germination rate of e-beam-treated seeds). These effects should be considered to obtain acceptable hygienic, nutritional and sensory attributes of irradiated Chinese cabbage seeds.Practical ApplicationsThe sprouted seeds widely used for human consumption are the suspect carriers of bacterial pathogens, which can outbreak sprout-related foodborne illnesses. Irradiation treatment is a promising technology to increase shelf life of sprouts and reduce bacterial pathogen contamination with minimum concession of nutritional and sensory aspects. However, it is significant to establish the effect of applied irradiation dose on the seed germination, sprout length, quality parameters and overall acceptability.

In computed tomography (CT) imaging, radiation dose delivered to the patient is one of the major concerns. Many CT developers and researchers have been making efforts to reduce radiation dose. Sparse-view CT takes projections at sparser view-angles and provides a viable option to reducing radiation dose. However, a fast power switching of an x-ray tube, which is needed for the sparse-view sampling, can be challenging in many CT systems. We have recently proposed a novel alternative approach to sparse-view circular CT that can be readily incorporated in the existing CT systems. Instead of switching the x-ray tube power, we proposed to use a multi-slit collimator placed between the x-ray source and the patient to partially block the x-ray beam thereby reducing the radiation. In this study, we performed a simulation study based on numerically acquired projection data to demonstrate a feasibility of using a multi-slit collimator in a helical CT. The XCAT phantom was used and a numerical collimator has been made to apply on the projection data. Numerical multi-slit collimator was designed to have equal size of slit-openings and radio-opaque rectangular areas, and the length dimension of the slits is perpendicular to the rotation axis. For image reconstruction, we used a total-variation minimization (TV) algorithm which has shown its out-performance in many sparse-view CT applications. We demonstrated that the proposed multiple fan-beam helical CT can provide a useful low-dose scanning option.

반응표면분석법을 이용하여 적양배추 종자의 전자선 처리조건과 재배조건에 따른 새싹채소의 이화학적 및 관능적 품질특성을 분석하여 유통에 적합한 최적조건을 모색하였다. 수분함량의 경우 회귀식의 $R^2$가 0.9638이었고 조사선량 및 재배기간에 많은 영향을 받고 있었다. Total phenolics 함량은 회귀식의 $R^2$가 0.9117이었고 조사선량에 많은 영향을 받았으며, carotenoid 함량($R^2$=0.8338)의 경우 조사선량, 재배기간, 저장기간의 순으로 조건 변수의 영향력이 작용하였다. 관능적 품질 역시 전자선 조사선량에 가장 크게 영향을 받아 선량의 증가에 따라 관능평점이 감소하는 경향을 보여주었다. 재배 및 저장조건의 최적화를 위해 total phenolics 함량 및 전반적 기호도를 superimposing한 결과 최적조건은 조사선량 2.2-3.8 kGy, 재배기간 3.0-4.0일 및 저장기간 2.0-3.0일 범위로 예측되었다. This study was carried out to find the optimal conditions for red cabbage seed sprouts in terms of their physicochemical and sensory qualities by electron-beam irradiation, cultivation and storage using the response surface methodology (RSM). Moisture content ($R^2$=0.9638) was affected by irradiation dose and cultivation time. Total phenolics content ($R^2$=0.9117) was mainly affected by irradiation dose, but carotenoid content ($R^2$=0.8338) was affected in the order of irradiation dose, cultivation time and storage time. Sensory properties were also affected by irradiation dose, and thus scores decreased as irradiation dose increased. The optimum conditions estimated by superimposing total phenolics content and overall acceptance were 2.2-3.8 kGy of the irradiation dose, 3.0-4.0 days of cultivation and 2.0-3.0 days of storage.

Electron accelerators were introduced in Korea during 1970s, firstly for research and later for insulated wire and cable production, and at present, over 60 electron accelerators are in commercial use providing several billion USD annually in Korean industries, mainly for wire and cable productions, thermo-shrinkable materials, foam sheets, coating and curing, sterilization of medical products, environmental protections, and others. With the increasing needs in the automobile and electronics industries, the applicable area of electron accelerator will be extended widely in future. Electron Accelerators are the most common means of radiation processing and they are used in diverse industries to enhance the physical and chemical properties of materials and to reduce undesirable contaminants, such as pathogens or toxic by-products of materials. Electron accelerators are reliable and durable electrically-sourced equipment that can produce ionizing radiation when it is needed for a particular commercial use.

Electron Accelerators are the most common means of radiation processing, and they are used in diverse industries to enhance the physical and the chemical properties of materials and to reduce undesirable contaminants, such as pathogens or toxic by-products of materials. Fifteen thousand [1,500] electron accelerators are commercially used in the world, and this number is eight or nine times greater than the number of Gamma irradiation facilities. Electron accelerators are reliable and durable electrically-sourced equipment that can produce ionizing radiation when it is needed for a particular commercial use. Electron accelerators were introduced in Korea during the 1970s, firstly for research and later for insulated wire and cable production. At present, over sixty electron accelerators are in commercial use, providing several billion USD annually in Korean industries, mainly for purposes such as, productions of wires, cables, thermo-shrinkable materials, foam sheets, and coating, curing of materials, sterilization of medical products, environmental protection, and others. With the increasing needs in the automobile and electronics industries, applicable areas for electron accelerator will be extended greatly in the future.

Textile dyeing processes consume large amount of water, steam and discharge filthy and colored wastewater. A pilot scale e-beam plant with an electron accelerator of 1MeV, 40kW had constructed at Daegu Dyeing Industrial Complex (DDIC) in 1997 for treating 1,000m3 per day. Continuous operation of this plant showed the preliminary e-beam treatment reduced bio-treatment time and resulted in more significant decreasing TOC, CODCr, and BOD5. Convinced of the economics and efficiency of the process, a commercial plant with 1MeV, 400kW electron accelerator has constructed in 2005. This plant improves the removal efficiency of wastewater with decreasing the retention time in bio-treatment at around 1kGy. This plant is located on the area of existing wastewater treatment facility in DDIC and the treatment capacity is 10,000m3 of wastewater per day. The total construction cost for this plant was USD 4M and the operation cost has been obtained was not more than USD 1M per year and about USD 0.3 per each m3 of wastewater.