Design of a combined ozone/electron beam process for waste water and economic feasibility of the process

A design of a combined ozone/electron beam irradiation process for treating a 50 m³/h waste water stream from a molasses processing is discussed. Moreover, a cost evaluation of such a process in comparison to a conventional ozonation/biology treatment process has been performed to assess the potential of the irradiation process for technical use. Although the result of this comparison is not bad for the irradiation process an implementation into a full scale plant would not seem to be the thing to do in the present case.     

Improvement of municipal wastewaters by electron beam accelerator in Brazil

Radiation processing of municipal sewage and sludge has been considered not only for disinfection but also for solids and organic matter removal in Brazil. The improvement of irradiated systems were demonstrated by the elimination of indicator bacteria and by the reduction on the total bacteria count, on the chemical and biochemical oxygen demand from raw sewage and biologically treated effluents. The selected doses of radiation to be applied to sewage and sewage sludge are in the range of 3.0 to 4.0 kGy to sewage and 4.0 to 6.0 kGy to sewage sludge.     

Remotion of organic compounds of actual industrial effluents by electron beam irradiation

Organic compounds has been a great problem of environmental pollution, the traditional methods are not effecient on removing these compounds and most of them are deposited to ambient and stay there for long time causing problems to the environment. Ionizing radiation has been used with success to destroy organic molecules. Actual industrial effluents were irradiated using IPEN's electron beam wastewater pilot plant to study organic compounds degradation. The samples were irradiated with and without air mixture by different doses. Irradiation treatment efficiency was evaluated by the Cromatography Gas Analyses of the samples before and after irradiation. The studied organic compounds were: phenol, chloroform, tetrachloroethylene (PCE), carbon tetrachloride, trichloroethylene (TCE), 1,1-dichloroethane, dichloromethane, benzene, toluene and xilene. A degradation superior to 80% was achieved for the majority of the compounds with air addition and 2kGy delivered dose condition. For the samples that were irradiated without air addition the degradation was higher.     

A study on chemical composition of spices irradiated by electron beam

Quantitative changes in common organic acids and inorganic acids from spices irradiated by electron beam were studied by Dionex-4000i ion chromograph. The results showed that the acids content of either chilli or the five-spice powder⁽³⁾ irradiated with a dose of 9.94 kGy did not undergo significant changes in comparison with the control samples. The flavour composition in the five-spice powder irradiated by electron beam was also determined by Finnigan MAT-8230B gas chromatograph-mass spectrometer, and compared to the results by heating treatment (120°C, 30min). The comparison indicated that the effect of electron beam treatment on flavour composition was less than that of heating.     

Crosslinking of recycled polyethylene by gamma and electron beam irradiation

Recycling of polymeric materials is usually accompanied by degradation and deleterious properties. Irradiation crosslinking of recycling low density polyethylene by electron beam and gamma rays could be the solution to improve their properties. This paper presents a comparison on the effects of gamma and electron irradiation on virgin and recycled polyethylene. Their mechanical, thermal and chemical properties were analyzed. VPE samples shown higher crosslinking percentages than RPE samples in all range of doses studied, unirradiated RPE samples had higher values on their tensile properties than VPE. Percentage crystallinity was similar in all range of doses studied.     

10MeV 25KW industrial electron LINAC

A 10MeV 25KW plus class electron LINAC was developed for sterilisation of medical devices. The LINAC composed of a standing wave type single cavity prebuncher and a 2m electro-plated travelling wave guide uses a 5MW 2856MHz pulse klystron as an RF source and provides 25KW beam power at the Ti alloy beam window stably after the energy analysing magnet with 10MeV plus-minus 1 MeV energy slit. The practical maximum beam power reached 29 KW and this demonstrated the LINAC as one of the most powerful S-band electron LINACs in the world. The control of the LINAC is fully automated and the “One-Button Operation” is realised, which is valuable for easy operation as a plant system. 2 systems have been delivered and are being operated stably.     

电子束辐照与电化学还原联用技术——一种用于煤炭直接液化的新方法

对电子束辐照与电化学联用技术提高煤炭液化率的新型方法进行了研究。利用高能电子束对煤炭样品进行辐照,并通过四氢呋喃萃取出辐照后的可能产物并计算其提取率。实验结果发现,提取产率随着辐照剂量的增加而增加,并得到在氧气气氛下25 kGy的最佳辐照条件。辐照的样品进一步在氢氧化钠电解液中电化学还原液化,并采用元素分析法、傅里叶红外光谱法、阴极极化曲线法、核磁共振法和计时电流法等来检测辐照对煤炭电化学还原的影响。     

Graft polymerization of acrylamide onto LLDPE film by electron beam pre-irradiation in air and argon. II. Influence of mohr's salt

LLDPE film pre-irradiated by electron beam (EB) in air and argon was grafted in an aqueous acrylamide solution containing Mohr's salt in the concentration range 0.0025–2% The grafting rate and yield were strongly dependent on the Mohr's salt concentration, mainly as a result of chain termination. The exponential grafting rate dependence on the pre-irradiation dose was quite insensitive to a hundred-fold variation in Mohr's salt concentration. © 1995 John Wiley & Sons, Inc.     

Improvement of plant parameters of the ROBO gamma irradiation facility due to design modification

Two industrial scale, “ROBO” type ⁶⁰Co gamma irradiation facilities have recently been put into operation in Syria and Peru, and the dosimetry commissioning of both plants have been carried out to determine dose distribution within products and to calculate plant parameters such as efficiency, dose uniformity ratio and throughput. There are some design modifications between the two plants in connection with the location of the carriers with respect to the source plaque and also to each other. The effect of these construction modifications on the plant parameters is discussed in the analysis of the dose distribution data measured in the carriers with depth and height among the four irradiation rows on both sides of the source plaque. The plant parameters were also calculated for different product densities using the technical data of the facilities, and the calculated and measured results were compared to each other.     

The revival of electron beam irradiation curing of epoxy resin—materials characterization and supportive cure studies

Polymeric composite manufacturing is a large, rapidly growing and energy consuming industry, where there is an obvious and compelling need for innovative curing technologies conforming to energy efficiency and environmental protection trends. This has led to many research efforts to consider, or in some cases re‐consider, irradiation curing of polymer composites. However, there is still a stifling lack of knowledge of the fundamental mechanisms to obtain homogeneity in the irradiation curing of composites. The key issue of the irradiation curing process, i.e. homogeneous curing affected by electron beam dose and initiator concentration for an epoxy resin is the focus of this paper. The temperature profiles, microstructure, curing degree gradient, and thermomechanical properties of electron beam‐ irradiated epoxy resin were profiled and analyzed, and the results indicated that curing degree in the epoxy resin showed a relatively steady region and an accelerated decrease along the depth direction. It is revealed that there existed an optimal range of concentration of the initiator for irradiation curing of an epoxy resin system. The inhomogeneity in the irradiation‐induced crosslinking structure could be abated by adopting the properly applied irradiation energy and the matching between the irradiation dose and the concentration of the initiator. It can be deduced that for most of the composite products with large thickness, layer upon layer irradiation or irradiation from two sides could be more efficient to obtain a homogeneous crosslinking structure. Copyright © 2009 John Wiley & Sons, Ltd.     

The study of electron beam flue gas treatment for coal-fired thermal plant in Japan

The fundamental research work with simulated coal-fired flue gas was performed in JAERI to get basic data for electron beam treatment of flue gas from thermal power plants in Japan. The standard condition of the experiments was set to be the same as that of next large scale pilot test in Nagoya. The concentrations of NO_x and SO_x were 225 ppm and 800 ppm, respectively. The temperature of the system was 65°C. The effect of multiple irradiation was observed for NO_x removal. The target SO_x and NO_x removals (94% and 80%, respectively) with low NH₃ leakage (less than 10 ppm) were achieved at 9 kGy irradiation with 0.9 NH₃ stoichiometry during 7 hours continuous operation. The facility for the pilot plant (12,000 Nm³/hr) has just built at the site of Shin-Nagoya power plant of Chubu Electric Power Company and will be started in full operation in November 1992.     

Influence of gas flow patterns on NOx removal efficiency

Dose distribution in flue gas irradiation vessel is not uniform due to limited electron penetration range. This phenomena influence overall NO_x removal efficiency is observed in the process. The remarkable increase in the efficiency can be achieved by multistage gas irradiation and gas mixing between stages. The results of modelling for longitudinal beam scanning as applied at EPS Kawêczyn pilot plant are presented in the paper. These are the basis for process vessel upscaling.     

Ultrahigh‐molecular‐weight‐polyethylene‐fiber surface treatment by electron‐beam‐irradiation‐induced graft polymerization and its effect on adhesion in a styrene–butadiene rubber matrix

Aiming to develop a high‐performance fiber‐reinforced rubber from styrene–butadiene rubber (SBR), we applied a special technique using electron‐beam (EB)‐irradiation‐induced graft polymerization to ultrahigh‐molecular‐weight‐polyethylene (UHMWPE) fibers. The molecular interaction between the grafted UHMWPE fibers and an SBR matrix was studied through the evaluation of the adhesive behavior of the fibers in the SBR matrix. Although UHMWPE was chemically inert, two monomers, styrene and N‐vinyl formamide (NVF), were examined for graft polymerization onto the UHMWPE fiber surface. Styrene was not effective, but NVF was graft‐polymerized onto the UHMWPE fibers with this special method. A methanol/water mixture and dioxane were used as solvents for NVF, and the effects of the solvents on the grafting percentage of NVF were also examined. The methanol/water mixture was more effective. A grafting percentage of 16.4% was the highest obtained. This improved the adhesive force threefold with respect to that of untreated UHMWPE fibers. These results demonstrated that EB irradiation enabled graft polymerization to occur even on the inert surface of UHMWPE fibers. However, the mechanical properties of the fibers could be compromised according to the dose of EB irradiation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2595–2603, 2004     

Microstructure analysis of a bronze–steel electron beam weld

An electron beam welded joint of bronze and steel has been investigated by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The phases and the resulting microstructure in the different zones of the joint have been characterised in detail and compared to hardness. The fine grained microstructure of the weld zone is partly dominated by the directed solidification of the melt. It mainly consists of the α-copper solid solution phase, the intermetallic δ phase Cu₃₁>Sn₈> as well as the bainitic and the martensitic steel phase. This mixture results in a considerably increase in hardness compared to base materials. The heat affected zone of bronze shows a refinement of the used dendritic cast material in a very small area. In the heat affected zone of the mild steel the change of microstructure depends on the distance from the weld zone due to the influence of thermal energy impact and heat dissipation. A maximum of hardness is reached nearby the weld due to the formation of bainite and martensite. The resulting hardness profile is asymmetrical.     

Preparation of poly(ε-caprolactone)-co-poly(acrylic acid) by radiation-induced grafting

Acrylic acid was grafted onto poly(ε-caprolactone) (PCL) films by using electron beam (EB) preirradiation technique. The effect of reaction time, monomer concentration, radiation dose, time between irradiation and grafting, radiation atmosphere, and polymer crystallinity on the extent of grafting were studied. Silver and tin ions were attached to the grafted chains in order to study the grafting process. The irradiation in air was initially more rapid, but the final extent of grafting was the same when irradiated in nitrogen atmosphere. Maximum grafting extents exceeding 400% could be obtained. The optimal grafting was obtained at an acrylic acid to water ratio of 30 : 70. The grafting process could be initiated at a dose as low as 12 kGy. The grafting process proved to start at the surface and was extended into the bulk with time. The ability to form crystals was reduced as the grafting extent increased. The water uptake of the poly(ε-caprolactone)-graft-poly(acrylic acid) was increasing with increasing grafting extent, but reached a maximum of ca 100% for all grafting extents above 85%. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1805–1812, 1998     

Detection of irradiated food: DNA fragmentation in grapefruits

Employing the simple microgel electrophoresis of single cells - ‘comet assay’ - on grapefruit seeds enabled a rapid identification of irradiated fruits. Fruits were exposed to radiation doses of 0, 0.1, 0.2, 0.3, 0.4 and 0.5 kGy covering the range of potential commercial irradiation for insect disinfestation and quarantine purposes. Seeds were isolated, crushed, and the cells embedded in an agarose layer. After lysis of the cells, they were subjected to microgel electrophoresis for 2.5 minutes, and then stained. Fruits irradiated with 0.2 kGy and higher doses showed typical DNA fragmentation, the DNA fragments stretching or migrating out of the cells forming a tail towards the anode, giving the damaged cells an appearance of a comet. With increasing dose a longer extension of the DNA from the nucleus towards the anode is observed. Undamaged cells will appear as intact nuclei without tails. The DNA comet assay is thus a rapid and inexpensive screening technique to detect irradiated grapefruits. Suspected samples may subsequently be analysed by officially validated methods for detection of irradiated foods.     

Improvements of physical and mechanical properties of electron beam irradiation—crosslinked EVA foams

In this work, ethylene–vinyl acetate (EVA) copolymer foams were prepared and crosslinked by using high‐energy electron beam (e‐beam) radiation (10 MeV). The effect of parameters such as irradiation dose, the contents of foaming agent, radiation activator, and radiation sensitizer on improvement of physical and mechanical properties of the EVA foamed samples were investigated. The foams were obtained through a four‐step process of melt mixing, forming, crosslinking, and foaming. During the melt mixing process EVA was compounded with different amounts of azodicarbonamide (ADCA) as a blowing agent, zinc oxide (ZnO) as a radiation activator, and trimethylol propane‐trimethacrylate (TMPTMA) as a radiation sensitizer. The samples were compression molded into flat sheets at low temperature (110°C) and were then radiation‐crosslinked by 20–80 kGy e‐beam. Finally, the crosslinked samples were converted to foams by a high temperature (210°C) compression molding process. The foamed samples were analyzed in terms of gel content, density, compression molding set, tensile properties, and micro‐structural features. It was found that an increase in absorbed radiation dosage increases crosslink density, elasticity, percentage recovery, tensile strength, and compression properties of the EVA foams. Due to the increased recovery the percentage of compression set was reduced. Similarly increasing the TMPTMA content in the formulation increased the crosslink density and the resulting mechanical properties. Contrary to these findings, addition of ADCA led to the formation of extra gases which in turn reduced the crosslink density, and resulted in the deterioration of the mechanical properties and hence an increase in the compression set. However, addition of ZnO and TMPTMA led to the formation of smaller and more uniform cell size with improved mechanical properties. Copyright © 2008 John Wiley & Sons, Ltd.     

Rheological changes in irradiated chicken eggs

Pathogenic bacteria may cause foodborne illnesses. Humans may introduce pathogens into foods during production, processing, distribution and or preparation. Some of these microorganisms are able to survive conventional preservation treatments. Heat pasteurization, which is a well established and satisfactory means of decontamination/disinfection of liquid foods, cannot efficiently achieve a similar objective for solid foods. Extensive work carried out worldwide has shown that irradiation is efficient in eradicating foodborne pathogens like Salmonella spp. that can contaminate poultry products. In this work Co-60 gamma irradiation was applied to samples of industrial powder white, yolk and whole egg at doses between 0 and 25 kGy. Samples were rehydrated and the viscosity measured in a Brookfield viscosimeter, model DV III at 5, 15 and 25°C. The rheological behaviour among the various kinds of samples were markedly different. Irradiation with doses up to 5 kGy, known to reduced bacterial contamination to non-detectable levels, showed almost no variation of viscosity of irradiated egg white samples. On the other hand, whole or yolk egg samples showed some changes in rheological properties depending on the dose level, showing the predominance of whether polimerization or degradation as a result of the irradiation. Additionally, irradiation of yolk egg powder reduced yolk color as a function of the irradiation exposure implemented. The importance of these results are discussed in terms of possible industrial applications.     

Modification of microstructures and physical properties of ultra high molecular weight polyethylene by electron beam irradiation

An ultra high molecular weight polyethylene was irradiated with the electron beam at dose levels ranging from 100 kGY to 1 MGy. The microstructures of the irradiated samples were characterized by FTIR, gel fraction measurement, DSC, and small‐ and wide‐angle X‐ray scattering. For the mechanical properties, a static tensile test and creep experiment were also performed. The crosslinking and the crystal morphology changes were the main microstructural changes to influence the mechanical properties. It was found that 250 kGy appeared to be the optimal dose level to induce crosslinks in the amorphous area and recrystalliztion in the crystal lamellae. At doses above 250 kGy, the electron beam penetrates into the crystal domains, resulting in crosslinks in the crystal domains and reduction in the crystal size and crystallinity. The static mechanical properties (modulus, strength) and the creep resistance were enhanced by the electron beam irradiation. The stiffness rather correlated with the degree of crosslinks while the strength with the crystal morphology. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3019–3029, 2005     

Consumer attitudes to radiation and irradiated potatoes at “radiation fair” in Osaka, Japan

“Radiation Fair” has been held in summer vacation season in August for more than 10 years in Osaka, the largest city of western Japan, for the purpose of public education and information transfer of radiation and radiation-related technology. We distributed questionnaires to the visitors for recent 3 years to inquire their status toward radiation and irradiated products including irradiated potatoes as well as impression toward the displays. According to the survey results, more than 60% of the kids visitors were satisfied with this exhibition as informative, more than half of the older visitors (16 years old and upward) indicated that they recognized the word of “radiation” when they were at elementary school and the most significant sources of this information were school lessons and the mass media. Consumer's image toward radiation seems to shift to more “positive” when correct knowledge about radiation is given. More than half of consumers did not know “irradiated potatoes” but the percentage indicating that irradiated potatoes was definitely hazardous was less than 10%.