Application of radiation processing for drinking water, wastewater, and groundwater treatment is ... more Application of radiation processing for drinking water, wastewater, and groundwater treatment is a cost effective process which may insure adequate availability of that resource worldwide. This paper summarizes the results of a Coordinated Research Project (organized by the IAEA) with participants from 10 countries with the purpose of describing the degradation mechanism of organic impurities, and establishing optimal treatment conditions. Decoloration, disinfection, microbiological and toxicological experiments are also mentioned. These experiments led to pilot plants and also to a large scale industrial realization of radiation technology.
The purpose of this work is to settle a laboratory for Iridium -192 sources production, that is, ... more The purpose of this work is to settle a laboratory for Iridium -192 sources production, that is, to determine a wire activation method and to build a hot cell for the wires manipulation, quality control and packaging. The paper relates, mainly, the wire activation method and its quality control. The wire activation is carried out in our nuclear reactor, IEA- R1m.
The aim of this work is to emphasize the importance of a previous study of the materials composit... more The aim of this work is to emphasize the importance of a previous study of the materials composition and behavior of any art work which will be treated by gamma radiation, as well as to use complementary procedures to prevent recontamination after the treatment, since this is a non residual method. As an example the object of study is a
A legislação brasileira requer que os substratos turfosos sejam pré-esterilizados através de radi... more A legislação brasileira requer que os substratos turfosos sejam pré-esterilizados através de radiação gama ( 60 Co), sendo recomendada a dose de 50 kGy para uma efetiva eliminação de patógenos e saprófitas, que podem competir com a bactéria introduzida. Recentemente, a utilização de feixe de elétrons foi considerada uma nova alternativa de radiação para préesterilização da turfa, com vantagens sobre a primeira técnica, por ser considerada ecologicamente mais segura e apresentar a vantagem de ser mais rápida. Há, porém, a desvantagem de ter menor profundidade de penetração da radiação em relação ao 60 Co. O presente trabalho comparou o método usando doses crescentes de radiação gama por 60 Co (0, 10, 20, 30, 50 e 50 kGy) e o método por feixe de elétrons (0, 10, 20, 30, 50 e 50 kGy). Nos dados experimentais observou-se um elevado número de células da bactéria Rhizobium tropici CM-01 Gus + inoculada em substratos turfosos submetidos aos dois processos de esterilização, sendo que ambos processos podem atender aos padrões mínimos requeridos pelas normas brasileiras e internacionais de qualidade de inoculantes pelo prazo de validade de 180 dias -acima de 1x10 7 ufc/g de substrato, após realizados os devidos de testes de sobrevivëncia com a bactéria inoculante. Pelos dados apresentados neste trabalho conclui-se que a esterilização por radiação por feixe de elétrons se apresenta como uma alternativa efetiva para a produção de inoculantes de alta qualidade, por controlar melhor os agentes antagonistas da bactéria.
Surgical gamma probes have been widely used in oriented surgery, to locate the sentinel lymph nod... more Surgical gamma probes have been widely used in oriented surgery, to locate the sentinel lymph nodes in breast cancer and malignant melanoma during the surgery. In this technique, the intra-operative localisation of the sentinel lymph node is carried out using a surgical gamma probe. A radiotracer, such as colloidal suspensions of 99m Tc in human albumin emitting γ-rays of 140 keV is administered (in the tumour site or close) in the patient, before operation, and the radiotracer travels from the tumour to the sentinel lymph node. Then the probe measures the labelled radioactivity, identifying and locating the sentinel lymph node once a visually occult disease, in order to remove it surgically. In this work, a pilot group of surgical gamma probes were developed at IPEN/CNEN-SP with high nationalisation indices, included the detector set. The probes final sizes were 14.0 mm diameter and 170 mm long and their characteristics were compared with imported probes and finally they were used in actual surgeries.
... Cláudio Boghi 1 , Celia M. Napolitano 1 , Danilo C. Ferreira 1 , Herman S. Zarate 2 and ... a... more ... Cláudio Boghi 1 , Celia M. Napolitano 1 , Danilo C. Ferreira 1 , Herman S. Zarate 2 and ... a) Studies for determination of the best way of blood bags load inside the irradiation chamber, with the intention to get the lower relation between maximum and minimum absorbed doses. ...
In this work, two computed tomography systems were developed for industrial application. The firs... more In this work, two computed tomography systems were developed for industrial application. The first one was of the first generation, which use a 5.08 cm (2") NaI(Tl) detector. The second was developed with a 40 cm bar of plastic scintillator detector using two phototubes in its extremities in order to be used as a sensitive position detector. In both systems a 60 Co source was used to carry out the CT experiments. The data acquisition board, the mechanical control interface and the software were specially developed in our laboratory to be used in this project. The tomography systems were tested using a phantom placed between the detector and a collimated 60 Co source. The source activity was of 12 MBq (325 µCi). The phantom used was the standard phantom designed and prepared by the University of Bergen (Norway). The phantom is composed of solid polypropylene with 400 mm diameter with two 50 mm diameter holes. The phantom was placed between the 60 Co source and the detector colli...
In industrial irradiators, the generated electromagnetic radiation or particles, such as gamma or... more In industrial irradiators, the generated electromagnetic radiation or particles, such as gamma or X rays and electrons interact with air during the irradiation of products. In this gas layer, these effects cause the radiolysis in the constituent atoms, affecting mainly the oxygen atoms. This interaction is similar to what occurs in the stratosphere, when the diatomic molecule of oxygen (O 2) absorbs ultraviolet radiation from the sun, breaking the connection and separating it into two highly reactive atoms, which combined with another molecule of oxygen produce ozone (O 3). Ozone, at high altitudes, is beneficial and protects us from ultraviolet radiation. At low altitudes, it is a highly oxidizing gas and harmful to living beings. Aiming to study the formation and behavior of this gas in gamma irradiators, the measurements were made at a Multipurpose Gamma Facility from IPEN / CNEN-SP, which has cobalt-60 sources with a total activity of 5.22 PBq.
A new type compact gamma irradiator was developed and installed at IPEN-CNEN/SP, it is classified... more A new type compact gamma irradiator was developed and installed at IPEN-CNEN/SP, it is classified as category IV irradiator according to International Atomic Energy Agency—IAEA. The originality of its design remains on the rotating concrete door, which integrates the shielding system with the product handling system, permitting the input and output of the products in a continuous way, without the necessity to lower the sources and open the irradiator chamber to change the batch. The licensed capacity of this irradiator is 37 PBq (1 MCi) and the water pool liner, manufactured in stainless steel, has 7.0 m deep and 2.7 m diameter. A sealed radiation source may be defined as a quantity of radioactive material sealed within non-radioactive material, which the confining barrier is intended to prevent leakage or escape of the radioactive material under normal handling conditions and also under foreseeable mishaps. The use of cobalt-60 radiation sources in a wet storage environment require...
Para complementar o levantamento radiométrico realizado no Irradiador Multipropósito do tipo comp... more Para complementar o levantamento radiométrico realizado no Irradiador Multipropósito do tipo compacto construído no Instituto de Pesquisas Energéticas e Nucleares (CNEN/SP-IPEN) [1] foram posicionados 12 dosímetros termoluminescentes, TLD, dentro da instalação em torno da câmara de irradiação e 8 unidades na área externa em pontos próximos ao prédio. Durante o segundo período de monitoração ocorreram a chegada de dois contêineres contendo fontes seladas de 60 Co (3,4 PBq e 9,2 Bq), o carregamento das fontes nos racks dentro da piscina de armazenamento e a irradiação de vários tipos de produtos. Os dosímetros CaSO 4 :Dy/PTFE vem sendo utilizados em várias instalações devido à sua robustez esensibilidade para fótons. As avaliações dos TLD foram conduzidos no Laboratório de Dosimetria Termoluminescente no Centro de Metrologia das Radiações. Utilizando-se a grandeza dosimetrica exposição para fótons em ar, os resultados mostraram que somente em um ponto o valor de exposição é mais alto que o nível de registro para indivíduos ocupacionalmente expostos e nos demais pontos os valores de exposição são próximos à radiação natural de fundo. O ponto onde a exposição é mais alta se deve ao fato da presença temporária do contêiner contendo fontes seladas de 60 Co (9,2 PBq) na parte de trás da blindagem do irradiador. Após a remoção do referido contêiner provavelmente a exposição diminuirá a valores da radiação natural de fundo. A grandeza operacional utilizada neste trabalho para a monitoração individual externa foi a dose equivalente para fótons, que é a grandeza oficialmente em uso no Brasil [2]. Pôde ser observado que a segurança radiológica da instalação é adequada tanto para indivíduos ocupacionalmente expostos quanto para indivíduos do público em condições normais de trabalho. É importante enfatizar que, em sendo os valores de exposição muito baixos dentro e nas proximidades da instalação, não existe impacto radiológico ao meio ambiente.
ABSTRACT The radiation processing technology for industrial and environmental applications has be... more ABSTRACT The radiation processing technology for industrial and environmental applications has been developed and used worldwide. In Latin America and the Caribbean and particularly in Brazil there are 24 and 16 industrial electron beam accelerators (EBA) respectively with energy from 200 keV to 10 MeV, operating in private companies and governmental institutions to enhance the physical and chemical properties of materials. However, there are more than 1500 high-current electron beam accelerators in commercial use throughout the world. The major needs and end-use markets for these electron beam (EB) units are R and D, wire and electric cables, heat shrinkable tubes and films, PE foams, tires, components, semiconductors and multilayer packaging films. Nowadays, the emerging opportunities in Latin America and the Caribbean are paints, adhesives and coatings cure in order to eliminate VOCs and for less energy use than thermal process; disinfestations of seeds; and films and multilayer packaging irradiation. For low-energy EBA (from 150 keV to 300 keV). For mid-energy EBA (from 300 keV to 5 MeV), they are flue gas treatment (SO2 and NOX removal); composite and nanocomposite materials; biodegradable composites based on biorenewable resources; human tissue sterilization; carbon and silicon carbide fibers irradiation; irradiated grafting ion-exchange membranes for fuel cells application; electrocatalysts nanoparticles production; and natural polymers irradiation and biodegradable blends production. For high-energy EBA (from 5 MeV to 10 MeV), they are sterilization of medical, pharmaceutical and biological products; gemstone enhancement; treatment of industrial and domestic effluents and sludge; preservation and disinfestations of foods and agricultural products; soil disinfestations; lignocellulosic material irradiation as a pretreatment to produce ethanol biofuel; decontamination of pesticide packing; solid residues remediation; organic compounds removal from wastewater; and treatment of effluent from petroleum production units and liquid irradiation process to treat vessel water ballast. On the other hand, there is a growing need of mobile EB facilities for different applications in South America.
Gamma-rays utilized as a food-processing treatment to eliminate insect contamination is well esta... more Gamma-rays utilized as a food-processing treatment to eliminate insect contamination is well established in food industries. Recent troubles in Brazilian cereal bars commercialization require a special consumer's attention because some products were contaminated by insects. To solve the problem, food-irradiation treatment was utilized as a safe and effective solution. The final product was free of insect contamination. The aim of
Polypropylene (PP) ®bers were grafted with methylmethacrylate. Eects of direct and pre-irradiatio... more Polypropylene (PP) ®bers were grafted with methylmethacrylate. Eects of direct and pre-irradiation method and monomer concentration on the degree of grafting were investigated. The grafted PP ®bers were characterized by swelling measurements, IR spectroscopy and by its mechanical and thermal properties. It was found that the direct method was more ecient than the indirect or pre-irradiation method and the monomer concentration for highest degree of grafting was 40% of MMA. Mechanical properties (tensile strength) and thermal stability decrease with grafting yield. Those changes were related to degradation of tie molecules between crystals and formation of rigid branches of PMMA on PP amorphous phase. #
For ages, herbs have been used as medicine and food. Nowadays, the interest in phytotherapeutics ... more For ages, herbs have been used as medicine and food. Nowadays, the interest in phytotherapeutics is increasing as well as the consumer attention. Some biochemical compounds synthesized by plants as alkaloids, phenolics, flavonoids, essential oils, tannins and vitamins, influence the composition of these plant pharmacologicals, which may produce various reactions in the human body. The microbial contamination in these raw plant materials is common, and the radiation processing is one appropriate technique for the reduction of microorganism. In herbs used as food products, the changes in total b-carotene and flavonoids upon the radiation treatment were tested. The powdered and dehydrated herbs were irradiated with 60 Co gamma rays applying doses of 0, 10, 20 and 30 kGy. The botanical species investigated were rosemary (Rosmarinus officinalis Linn! e), watercress (Nasturtium officinale R. Br), artichoke (Cynara scolymus Linn! e) and sweet basil (Ocimum basilicum Linn! e). The alterations in the active principles in the herbs following increasing doses of radiation were analyzed employing various methods of extraction and chromatography. r
A new small size gamma irradiator is being set up at Instituto de Pesquisas Energeticas e Nuclear... more A new small size gamma irradiator is being set up at Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/ SP), Brazil, with a revolutionary design. The developed technology for this facility consists of continuous tote box transport system, comprising a single concrete vault, where the automated transport system of products inside and outside of the irradiator utilizes a rotating door, integrated with the shielding, avoiding the traditional maze configuration. Covering 76 m 2 of floor area, the irradiator design is product overlap sources and the maximum capacity of Cobalt-60 wet sources is 37 PBq (1 MCi). The irradiator is being installed in a Governmental Institution and it will be used as a demonstration facility for manufacturers, who need an economic and logistic in-house irradiation system alternative. Also, it will be useful for supporting the local scientific community on development of products and process using gamma radiation, assisting the traditional and potential users on process validation, training and qualification of operators and radioprotection officers. r
Application of radiation processing for drinking water, wastewater, and groundwater treatment is ... more Application of radiation processing for drinking water, wastewater, and groundwater treatment is a cost effective process which may insure adequate availability of that resource worldwide. This paper summarizes the results of a Coordinated Research Project (organized by the IAEA) with participants from 10 countries with the purpose of describing the degradation mechanism of organic impurities, and establishing optimal treatment conditions. Decoloration, disinfection, microbiological and toxicological experiments are also mentioned. These experiments led to pilot plants and also to a large scale industrial realization of radiation technology.
The purpose of this work is to settle a laboratory for Iridium -192 sources production, that is, ... more The purpose of this work is to settle a laboratory for Iridium -192 sources production, that is, to determine a wire activation method and to build a hot cell for the wires manipulation, quality control and packaging. The paper relates, mainly, the wire activation method and its quality control. The wire activation is carried out in our nuclear reactor, IEA- R1m.
The aim of this work is to emphasize the importance of a previous study of the materials composit... more The aim of this work is to emphasize the importance of a previous study of the materials composition and behavior of any art work which will be treated by gamma radiation, as well as to use complementary procedures to prevent recontamination after the treatment, since this is a non residual method. As an example the object of study is a
A legislação brasileira requer que os substratos turfosos sejam pré-esterilizados através de radi... more A legislação brasileira requer que os substratos turfosos sejam pré-esterilizados através de radiação gama ( 60 Co), sendo recomendada a dose de 50 kGy para uma efetiva eliminação de patógenos e saprófitas, que podem competir com a bactéria introduzida. Recentemente, a utilização de feixe de elétrons foi considerada uma nova alternativa de radiação para préesterilização da turfa, com vantagens sobre a primeira técnica, por ser considerada ecologicamente mais segura e apresentar a vantagem de ser mais rápida. Há, porém, a desvantagem de ter menor profundidade de penetração da radiação em relação ao 60 Co. O presente trabalho comparou o método usando doses crescentes de radiação gama por 60 Co (0, 10, 20, 30, 50 e 50 kGy) e o método por feixe de elétrons (0, 10, 20, 30, 50 e 50 kGy). Nos dados experimentais observou-se um elevado número de células da bactéria Rhizobium tropici CM-01 Gus + inoculada em substratos turfosos submetidos aos dois processos de esterilização, sendo que ambos processos podem atender aos padrões mínimos requeridos pelas normas brasileiras e internacionais de qualidade de inoculantes pelo prazo de validade de 180 dias -acima de 1x10 7 ufc/g de substrato, após realizados os devidos de testes de sobrevivëncia com a bactéria inoculante. Pelos dados apresentados neste trabalho conclui-se que a esterilização por radiação por feixe de elétrons se apresenta como uma alternativa efetiva para a produção de inoculantes de alta qualidade, por controlar melhor os agentes antagonistas da bactéria.
Surgical gamma probes have been widely used in oriented surgery, to locate the sentinel lymph nod... more Surgical gamma probes have been widely used in oriented surgery, to locate the sentinel lymph nodes in breast cancer and malignant melanoma during the surgery. In this technique, the intra-operative localisation of the sentinel lymph node is carried out using a surgical gamma probe. A radiotracer, such as colloidal suspensions of 99m Tc in human albumin emitting γ-rays of 140 keV is administered (in the tumour site or close) in the patient, before operation, and the radiotracer travels from the tumour to the sentinel lymph node. Then the probe measures the labelled radioactivity, identifying and locating the sentinel lymph node once a visually occult disease, in order to remove it surgically. In this work, a pilot group of surgical gamma probes were developed at IPEN/CNEN-SP with high nationalisation indices, included the detector set. The probes final sizes were 14.0 mm diameter and 170 mm long and their characteristics were compared with imported probes and finally they were used in actual surgeries.
... Cláudio Boghi 1 , Celia M. Napolitano 1 , Danilo C. Ferreira 1 , Herman S. Zarate 2 and ... a... more ... Cláudio Boghi 1 , Celia M. Napolitano 1 , Danilo C. Ferreira 1 , Herman S. Zarate 2 and ... a) Studies for determination of the best way of blood bags load inside the irradiation chamber, with the intention to get the lower relation between maximum and minimum absorbed doses. ...
In this work, two computed tomography systems were developed for industrial application. The firs... more In this work, two computed tomography systems were developed for industrial application. The first one was of the first generation, which use a 5.08 cm (2") NaI(Tl) detector. The second was developed with a 40 cm bar of plastic scintillator detector using two phototubes in its extremities in order to be used as a sensitive position detector. In both systems a 60 Co source was used to carry out the CT experiments. The data acquisition board, the mechanical control interface and the software were specially developed in our laboratory to be used in this project. The tomography systems were tested using a phantom placed between the detector and a collimated 60 Co source. The source activity was of 12 MBq (325 µCi). The phantom used was the standard phantom designed and prepared by the University of Bergen (Norway). The phantom is composed of solid polypropylene with 400 mm diameter with two 50 mm diameter holes. The phantom was placed between the 60 Co source and the detector colli...
In industrial irradiators, the generated electromagnetic radiation or particles, such as gamma or... more In industrial irradiators, the generated electromagnetic radiation or particles, such as gamma or X rays and electrons interact with air during the irradiation of products. In this gas layer, these effects cause the radiolysis in the constituent atoms, affecting mainly the oxygen atoms. This interaction is similar to what occurs in the stratosphere, when the diatomic molecule of oxygen (O 2) absorbs ultraviolet radiation from the sun, breaking the connection and separating it into two highly reactive atoms, which combined with another molecule of oxygen produce ozone (O 3). Ozone, at high altitudes, is beneficial and protects us from ultraviolet radiation. At low altitudes, it is a highly oxidizing gas and harmful to living beings. Aiming to study the formation and behavior of this gas in gamma irradiators, the measurements were made at a Multipurpose Gamma Facility from IPEN / CNEN-SP, which has cobalt-60 sources with a total activity of 5.22 PBq.
A new type compact gamma irradiator was developed and installed at IPEN-CNEN/SP, it is classified... more A new type compact gamma irradiator was developed and installed at IPEN-CNEN/SP, it is classified as category IV irradiator according to International Atomic Energy Agency—IAEA. The originality of its design remains on the rotating concrete door, which integrates the shielding system with the product handling system, permitting the input and output of the products in a continuous way, without the necessity to lower the sources and open the irradiator chamber to change the batch. The licensed capacity of this irradiator is 37 PBq (1 MCi) and the water pool liner, manufactured in stainless steel, has 7.0 m deep and 2.7 m diameter. A sealed radiation source may be defined as a quantity of radioactive material sealed within non-radioactive material, which the confining barrier is intended to prevent leakage or escape of the radioactive material under normal handling conditions and also under foreseeable mishaps. The use of cobalt-60 radiation sources in a wet storage environment require...
Para complementar o levantamento radiométrico realizado no Irradiador Multipropósito do tipo comp... more Para complementar o levantamento radiométrico realizado no Irradiador Multipropósito do tipo compacto construído no Instituto de Pesquisas Energéticas e Nucleares (CNEN/SP-IPEN) [1] foram posicionados 12 dosímetros termoluminescentes, TLD, dentro da instalação em torno da câmara de irradiação e 8 unidades na área externa em pontos próximos ao prédio. Durante o segundo período de monitoração ocorreram a chegada de dois contêineres contendo fontes seladas de 60 Co (3,4 PBq e 9,2 Bq), o carregamento das fontes nos racks dentro da piscina de armazenamento e a irradiação de vários tipos de produtos. Os dosímetros CaSO 4 :Dy/PTFE vem sendo utilizados em várias instalações devido à sua robustez esensibilidade para fótons. As avaliações dos TLD foram conduzidos no Laboratório de Dosimetria Termoluminescente no Centro de Metrologia das Radiações. Utilizando-se a grandeza dosimetrica exposição para fótons em ar, os resultados mostraram que somente em um ponto o valor de exposição é mais alto que o nível de registro para indivíduos ocupacionalmente expostos e nos demais pontos os valores de exposição são próximos à radiação natural de fundo. O ponto onde a exposição é mais alta se deve ao fato da presença temporária do contêiner contendo fontes seladas de 60 Co (9,2 PBq) na parte de trás da blindagem do irradiador. Após a remoção do referido contêiner provavelmente a exposição diminuirá a valores da radiação natural de fundo. A grandeza operacional utilizada neste trabalho para a monitoração individual externa foi a dose equivalente para fótons, que é a grandeza oficialmente em uso no Brasil [2]. Pôde ser observado que a segurança radiológica da instalação é adequada tanto para indivíduos ocupacionalmente expostos quanto para indivíduos do público em condições normais de trabalho. É importante enfatizar que, em sendo os valores de exposição muito baixos dentro e nas proximidades da instalação, não existe impacto radiológico ao meio ambiente.
ABSTRACT The radiation processing technology for industrial and environmental applications has be... more ABSTRACT The radiation processing technology for industrial and environmental applications has been developed and used worldwide. In Latin America and the Caribbean and particularly in Brazil there are 24 and 16 industrial electron beam accelerators (EBA) respectively with energy from 200 keV to 10 MeV, operating in private companies and governmental institutions to enhance the physical and chemical properties of materials. However, there are more than 1500 high-current electron beam accelerators in commercial use throughout the world. The major needs and end-use markets for these electron beam (EB) units are R and D, wire and electric cables, heat shrinkable tubes and films, PE foams, tires, components, semiconductors and multilayer packaging films. Nowadays, the emerging opportunities in Latin America and the Caribbean are paints, adhesives and coatings cure in order to eliminate VOCs and for less energy use than thermal process; disinfestations of seeds; and films and multilayer packaging irradiation. For low-energy EBA (from 150 keV to 300 keV). For mid-energy EBA (from 300 keV to 5 MeV), they are flue gas treatment (SO2 and NOX removal); composite and nanocomposite materials; biodegradable composites based on biorenewable resources; human tissue sterilization; carbon and silicon carbide fibers irradiation; irradiated grafting ion-exchange membranes for fuel cells application; electrocatalysts nanoparticles production; and natural polymers irradiation and biodegradable blends production. For high-energy EBA (from 5 MeV to 10 MeV), they are sterilization of medical, pharmaceutical and biological products; gemstone enhancement; treatment of industrial and domestic effluents and sludge; preservation and disinfestations of foods and agricultural products; soil disinfestations; lignocellulosic material irradiation as a pretreatment to produce ethanol biofuel; decontamination of pesticide packing; solid residues remediation; organic compounds removal from wastewater; and treatment of effluent from petroleum production units and liquid irradiation process to treat vessel water ballast. On the other hand, there is a growing need of mobile EB facilities for different applications in South America.
Gamma-rays utilized as a food-processing treatment to eliminate insect contamination is well esta... more Gamma-rays utilized as a food-processing treatment to eliminate insect contamination is well established in food industries. Recent troubles in Brazilian cereal bars commercialization require a special consumer's attention because some products were contaminated by insects. To solve the problem, food-irradiation treatment was utilized as a safe and effective solution. The final product was free of insect contamination. The aim of
Polypropylene (PP) ®bers were grafted with methylmethacrylate. Eects of direct and pre-irradiatio... more Polypropylene (PP) ®bers were grafted with methylmethacrylate. Eects of direct and pre-irradiation method and monomer concentration on the degree of grafting were investigated. The grafted PP ®bers were characterized by swelling measurements, IR spectroscopy and by its mechanical and thermal properties. It was found that the direct method was more ecient than the indirect or pre-irradiation method and the monomer concentration for highest degree of grafting was 40% of MMA. Mechanical properties (tensile strength) and thermal stability decrease with grafting yield. Those changes were related to degradation of tie molecules between crystals and formation of rigid branches of PMMA on PP amorphous phase. #
For ages, herbs have been used as medicine and food. Nowadays, the interest in phytotherapeutics ... more For ages, herbs have been used as medicine and food. Nowadays, the interest in phytotherapeutics is increasing as well as the consumer attention. Some biochemical compounds synthesized by plants as alkaloids, phenolics, flavonoids, essential oils, tannins and vitamins, influence the composition of these plant pharmacologicals, which may produce various reactions in the human body. The microbial contamination in these raw plant materials is common, and the radiation processing is one appropriate technique for the reduction of microorganism. In herbs used as food products, the changes in total b-carotene and flavonoids upon the radiation treatment were tested. The powdered and dehydrated herbs were irradiated with 60 Co gamma rays applying doses of 0, 10, 20 and 30 kGy. The botanical species investigated were rosemary (Rosmarinus officinalis Linn! e), watercress (Nasturtium officinale R. Br), artichoke (Cynara scolymus Linn! e) and sweet basil (Ocimum basilicum Linn! e). The alterations in the active principles in the herbs following increasing doses of radiation were analyzed employing various methods of extraction and chromatography. r
A new small size gamma irradiator is being set up at Instituto de Pesquisas Energeticas e Nuclear... more A new small size gamma irradiator is being set up at Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/ SP), Brazil, with a revolutionary design. The developed technology for this facility consists of continuous tote box transport system, comprising a single concrete vault, where the automated transport system of products inside and outside of the irradiator utilizes a rotating door, integrated with the shielding, avoiding the traditional maze configuration. Covering 76 m 2 of floor area, the irradiator design is product overlap sources and the maximum capacity of Cobalt-60 wet sources is 37 PBq (1 MCi). The irradiator is being installed in a Governmental Institution and it will be used as a demonstration facility for manufacturers, who need an economic and logistic in-house irradiation system alternative. Also, it will be useful for supporting the local scientific community on development of products and process using gamma radiation, assisting the traditional and potential users on process validation, training and qualification of operators and radioprotection officers. r
Uploads
Papers by Paulo Rela