PAULO DE SOUZA SANTOS

PAULO DE SOUZA SANTOS

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Gamma radiation processing for disinfection of a 19th century photo album
2021 - NAGAI, M.L.E.; SANTOS, P.S.; PARRON, I.; LEE, F.M.; VASQUEZ, P.
Development of methodologies for decontamination, reuse and improvement of the properties of respiratory protective equipment using ionizing radiation
2020 - VASQUEZ, P.A.S.; MORAIS, F.; LIMA, F.S.; SANTOS, P.S.; MORAES, O.; ARTAXO, P.; JOHN, V.M.; NAGAI, M.L.E.; OLIVEIRA, M.J.A.; CATALANI, L.H.; KODAMA, Y.; OTUBO, L.
Effect of ionizing radiation on the color of featherwork
2019 - VIEIRA, ANA C.D.; KODAMA, YASKO; OTUBO, LARISSA; SANTOS, PAULO de S.; VASQUEZ, PABLO A.
Featherwork collections are usually stored and managed by ethnographic museums. Even though the featherwork manufacturing is still practiced by the indigenous communities, the offer of raw material and the contact with the surrounding society ended up reducing the production scale of such objects. Consequently, the preservation of the culture heritage is very important, particularly in museums. Biodegradation can affect featherworks mainly by xylophagous insects and moths’ action. The tropical Brazilian weather contributes to the contamination and proliferation of insects and fungi making the preservation conditions difficult. The use of gamma radiation for the disinfection of cultural heritage objects and archived materials has shown to be a safe process and an excellent alternative to traditional methods usually involving high persistent and toxic chemical pesticides. In this work are presented the preliminary results of the ionizing radiation effects on the color and morphological properties of a featherwork from the Museum of Archeology and Ethnology of the University of São Paulo (MAE/USP). Samples of feathers were selected from the artifact and irradiated with gamma rays at the Multipurpose Gamma Irradiation Facility at IPEN, applying absorbed doses between 0.5 kGy to 200 kGy. Samples were firstly chosen according to feather colors, photographed and analyzed using colorimetry with CIELAB 1976 color space scale and scanning electron microscopy (SEM), just after and 48 hours after the irradiation process. The results shown had no significant changes on color and morphological properties within the disinfection absorbed dose range applied.
Effect of ionizing radiation on the color of botanical collections
2019 - LIMA, LENI M.P.R.; KODAMA, YASKO; OTUBO, LARISSA; SANTOS, PAULO de S.; VASQUEZ, PABLO A.
Conservation and preservation strategies are essential to manage botanical collections specially for dried herbarium specimens also known as exsiccates, usually referring to a set of identified specimens belonging to taxa and distributed among all herbaria around the world. Particularly, these collections are very sensitive to the attack of fungi and insects. In recent years, disinfection by ionizing radiation has become an effective strategy to preserve cultural heritage objects and archived materials with excellent results. In this work, the effects on color properties of gamma radiation on exsiccates samples were studied. Thus, six exsiccates, botanical pressed and dehydrated samples were selected from the Dom Bento José Pickel Herbarium (SPSF), situated at São Paulo (Brazil). Three of these samples comes from Asteraceae family and were collected in 1946, 1984 and 1986, while three other samples belong to Solanaceae family and were collected in 1953, 1984 and 2007. Families of selected botanical collections are very susceptible to biodegradation. The irradiation was performed at the Multipurpose Gamma Irradiation Facility at IPEN applying absorbed doses of 1 kGy, 6 kGy and 10 kGy, which are values of absorbed dose for disinfestation and disinfection. Results were analyzed using colorimetry with CIELAB color space scale and scanning electron microscopy. The results showed that there were no significant changes on colorimetric morphological properties of the samples.
Irradiation protocol for cultural heritage conservation treatment
2019 - NAGAI, MARIA L.E.; SANTOS, PAULO de S.; VASQUEZ, PABLO A.
Ionizing radiation supplied by cobalt-60 is an excellent alternative tool to the traditional process of decontamination of cultural and historical materials, mainly because of its biocidal action. Analyzing the occurrence of requests for treatment materials from cultural institutions with ionizing radiation for fungal decontamination in the Multipurpose Gamma Irradiation Facility of the Nuclear and Energy Research Institute - CTR/IPEN, there was a need to establish a protocol for the care of institutions and individuals carrying cultural and historical collections. The objective of the present study was the establishment of an efficient and reproducible model of an irradiation protocol for the treatment of cultural heritage materials in industrial irradiators. One of the main conditions of effective decontamination, resulting in the least possible deterioration of the materials due to the treatment, is the homogeneity of the mass of the materials to be treated. In this sense, it is important to establish and follow a protocol for the effective processing of ionizing radiation and to respect the ethical principles of conservation and restoration activities. The proposed protocol can also be applied to other types of files and collections. The decision to treat ionizing radiation should be conducted by professionals of conservation of cultural goods in agrément with professionals of the area of application of ionizing radiation. The objective of the protocol is to be a practical guide, from the detection of the problem to the final cleaning, so that conservatives and professionals of the irradiation can act in a collaborative and objective way to reach the objective of the treatment.
Radioactive sealed sources production process for industrial radiography
2017 - SANTOS, PAULO de S.; NGUNGA, DANIEL M.G.; CAMARA, JULIO R.; VASQUEZ, PABLO A.S.
Since 1983, the Sealed Source Production Laboratory at the Nuclear and Energy Research Institute has been providing products and services to the private and governmental Brazilian users of industrial radiography and nucleonic control systems. Radioactive sealed sources are commonly used in nondestructive tests as radiography to make inspections and verify the internal structure and integrity of materials and in nucleonic gauges to control level, density, viscosity, etc. in on-line industrial processes. One of the most important activities carried out by this laboratory is related to the inspection of source projectors devices used in industrial radiography and its constituent parts as well as remote handle control assembly drive cable and guide tube systems. The laboratory also provide for the users iridium-192, cobalt-60 and selenium-75 sealed sources and performs quality control tests replacing spent or contaminated radiative sources. All discard of radioactive source is treated as radioactive waste. Additionally, administrative and commercial processes and protocols for exportation and transport of radioactive material are developed by specialized departments. In this work are presented the mean processes and procedures used by the Sealed Source Production Laboratory such as the arrival of the radioactive material to the laboratory and the source projectors, mechanical inspections, source loading, source leaking tests, etc.
The effect of gamma radiation on the structure of graphene oxide and graphene oxide functionalized with amino-PEG
2017 - SOARES, JAQUELINE J.S.; JACOVONE, RAYNARA M.S.; SANTOS, PAULO S.; ZAIM, MARCIO H.; FARIA, DALVA L.A. de; SAKATA, SOLANGE K.
The functionalization of graphene oxide (GO) with polyethylene glycol (PEG) has been widely used in drug delivery systems. This nanocomposite exhibits excellent stability in the presence of high concentrations of salts and proteins and shows to be less toxic than its raw form in vitro and in vivo. However, it must be sterilized before use in the medical field and the gamma irradiation shows a promising option for this purpose. Sterilization by ionizing energy through gamma rays, generated by Cobalt-60 self-disintegration, consists in exposing the materials to short electromagnetic waves. The irradiation process provides substantial advantages when compared to thermal and chemical processes such as more precise control of the process, production of products with superior qualities, lower energy consumption and less environmental pollution. In this work the effect of gamma radiation on the structure of GO and GO functionalized com Amino-PEG (GO-PEG-NH2) irradiated with different doses (15, 25, 35 and 50 kGy) and rate dose 7.31 kGy.h-1 was evaluated. The analyses were performed by Fourier-transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The results showed that the methods for the synthesis of GO and GO-PEG-NH2 was effective since there was confirmation of the surface oxidation of materials and functionalization with the PEG-NH2 and the sterilization by gamma radiation does not caused any defects on materials.
C-188 CO-60 sources installation and source rack loading optimization processes in a gamma irradiation facility
2017 - SANTOS, PAULO de S.; VASQUEZ, PABLO A.S.
Since 2004, the Multipurpose Gamma Facility at the Nuclear and Energy Research Institute has been providing services on radiation processing for disinfection and sterilization of health care and disposable medical products as well to support research studies on modification of physical, chemical and biological properties of several materials. Recently, there was an increment in irradiation of the Cultural Heritages. This facility uses C-188 double-encapsulated radioactive Cobalt-60 sources kwon as pencils from manufactures outside of country. The activity of the cobalt sources decays into a stable nickel isotope with a half-life around 5.27 years, which means a loss of 12.3% annually. Then, additional pencils of Cobalt-60 are added periodically to the source rack to maintain the required capacity or installed activity of the facility. The manufacturer makes shipping of the radioactive sources inside a high density container type B(U) , by sea. This one involves many administrative, transport and radiation safety procedures. Once in the facility, the container is opened inside a deep pool water to remove the pencils. The required source geometry of the facility is obtained by loading these source pencils into predetermined diagram or positions in source modules and distributing these modules over the source rack of the facility. The dose variation can be reduced placing the higher activity source pencils near the periphery of the source rack. In this work are presented the procedures for perform the boiling leaching tests applied to the container, the Cobalt-60 sources installation, the loading processes and the source rack loading optimization.
Preservation of photographic and cinematographic films by gamma radiation- preliminary analyses
2017 - NAGAI, MARIA L.E.; SANTOS, PAULO S.; OTUBO, LARISSA; OLIVEIRA, MARIA J.A.; VASQUEZ, PABLO A.S.
Brazilian weather conditions affect directly tangible materials causing deterioration notably getting worse by insects and fungi attack. In this sense, gamma radiation provided from the cobalt-60 is an excellent alternative tool to the traditional preservation process mainly because it has biocidal action. Radiation processing using gamma radiation for cultural heritage materials for disinfection has been widely used around the world in the last decades. Many cultural heritage objects especially made on paper and wood were studied in scientific publications aiming mechanical, physical and chemical properties changes. Over the last fifteen years, the Multipurpose Gamma Irradiation Facility of the Nuclear and Energy Research Institute located inside the Sao Paulo University campus has been irradiated many collections of archived materials, books, paintings and furniture. Adequate storage of photographic and cinematographic materials is a challenge for conservators from preservation institutions. Contamination by fungi is one of leading causes of problem in photographic and cinematographic collections. Several Sao Paulo University libraries have been affected by fungi in their photographic and cinematographic collections making it impossible to research on these materials either manipulate them for health and safety reasons. In this work are presented preliminary results of effects of the ionizing radiation in photographic and cinematographic films. Selected film samples made on cellulose acetate were prepared and characterized by FTIR-ATR spectroscopy. Samples were irradiated by gamma rays with absorbed dose between 2 kGy and 50 kGy. Irradiated samples were analyzed by UV-VIS spectroscopy and electron microscopy techniques. Results shown that disinfection by gamma radiation can be achieved safely applying the disinfection dose between 6 kGy to 15 kGy with no significant change or modification of main properties of the constitutive materials.
Dose rate mapping near the sources racks
2011 - SANTOS, PAULO de S.; NAPOLITANO, CELIA M.; FERREIRA, DANILO C.; MEDEIROS, SALOMAO A.; SILVA, MANOEL E.; OMI, NELSON M.