Abstract: Ferrous alloys stand out for their use in various branches of the mechanical industry, as they encompass a series of mechanical properties that directly influence their application. For their implementation to be successful, they must have a suitable microstructure, which provides steel with sufficient mechanical characteristics so that it can withstand various types of efforts resulting from its implementation. Heat treatments are responsible for developing this microstructure in a controlled manner, through a set of heating and cooling operations with controlled conditions of temperature, time, atmosphere and cooling speed, in order to change their properties or give them some features. One of the most conventional treatments used worldwide to impart mechanical resistance to steels is the quenching treatment, which consists of heating the metal to austenitization temperature, kept at the same temperature for a certain time and after cooling it rapidly in a liquid medium. great efficiency in the extraction of heat, which can be water, saline solutions, polymeric solutions and oils, in order to form a new microstructure, harder but more fragile than its initial state, called martensite, which after tempering, has its stress-free internal structure, increasing its toughness. The most common cooling medium of the last decades is mineral oil, which due to its viscosity, has excellent capacity to extract heat, but it is a great villain when it comes to environmental issues, an example of this is the increase of water contamination. underground, where mineral oils are the most abundant contaminants present in the analyzed samples of these sources. Due to these and other environmental problems, studies have been developed to obtain an alternative cooling medium as effective as mineral oil, but which has less environmental impact. One solution to this problem is to use compound oils from renewable and biodegradable sources such as vegetable oils. Therefore, this work studies the effects of tempering on SAE 1045 carbon steel and AISI 420 martensitic stainless steel, using biodegradable soy and castor oil as cooling medium. For this, the viscosity of the oils was measured at room temperature and heated to 70 °C, temperatures at which tempering treatments were performed on 10 x 20 x 20mm rectangular section specimens. The specimens were cut, embedded and polished to be characterized by optical micrograph and Vickers microhardness. The results showed that biodegradable oils have excellent stability to bath temperature variation and can be applied over large temperature ranges due to their high flash points. Regarding the hardness and microstructure formed inside the specimen, the vegetable oils were also efficient, presenting values very similar to mineral oil, being soy oil more efficient than castor oil due to its low viscosity influencing hardness of the pieces and also in the formation of martensite. Biodegradable oils have proven to be an alternative.

BARTOLOMEI, S.S.; BARTOLOMEI, M.R.; SILVA, F.A.; OLIVEIRA, A.A. Use of biodegradable oils as an alternative cooling in quenching treatment. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020. Disponível em: http://repositorio.ipen.br/handle/123456789/31898. Acesso em: $DATA.

Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.

Como referenciar este item

Abstract: In this work, graphene oxide (GO) was synthesized by the modified Hummers method and was used as support for palladium nanoparticles to study its electrochemical behavior. The main objective was the incorporation of Pd on the graphene oxide by the electron beam irradiation at 40kGy and 80kGy doses. The GO-Pd nanocomposite was characterized by thermogravimetry analysis (TGA), X-ray diffraction (XRD), electron transmission microscopy (TEM), zeta potential analysis and cyclic voltammetry (CV). The results were satisfactory, indicating success in incorporating the metal in the GO surface. CV studies were conducted using screen printed electrode modified with nanocomposite, SPE/GO-Pd, at a scan rate of 50 mVs-1, potentials range from -0.5 V until 1.0 V in KCl medium (0.05 mol.L-1) adding aliquots of 4 mmol L ?1 ferricyanide solution and its results showed a linear increase in the current. It can therefore be inferred that palladium /graphene oxide nanocomposites have a potential for sensors.

CARNEIRO, F.W.; KAWABATA, V.J.; JACOVONE, R.M.; ANGNES, L.; GARCIA, R.H.; SAKATA, S.K. The synthesis of palladium nanoparticles by electron beam into graphene oxide and its electrochemical behavior. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020. Disponível em: http://repositorio.ipen.br/handle/123456789/31892. Acesso em: $DATA.

Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.

Como referenciar este item

Abstract: Eleven [Eu2(L)3(H2O)x]·y(H2O) complexes with aliphatic dicarboxylate ligands (L: OXA, MAL, SUC, GLU, ADP, PIM, SUB, AZL, SEB, UND, and DOD, where x=2–6 and y=0–4) were synthesized and characterized by elemental and thermal analysis, FTIR spectroscopy and powder X-ray diffraction. The obtained data confirms the ligand to metal ratio, the hydration degree, the coordination mode and that the complexes are crystalline. The oddeven effect was observed for the final dehydration temperature of the Eu3+ complexes (Fig. 1). Moreover, the effect was also observed in the experimental and theoretical photoluminescent properties such as the intensity parameters, Ω2 and Ω4 (Fig. 2) and the emission intrinsic quantum yield, QLnLn (Fig. 3) of the Eu3+ complexes. The odd-even effect on the Ω2 and Ω4 values could be explained by using an extension of the dynamic coupling mechanism, herein named the ghost-atom (GA) model, in which the long-range polarizabilities (α*) were determined by simulating the presence of a ghost atom in the middle of each ligand carbon chain and the localized molecular orbital approach. The GA approach is an extension of the Bond Overlap Model (BOM) [1].

ASSUNCAO, ISRAEL; NETO, ALBANO; MOURA JUNIOR, RENALDO; PEDROSO, CASSIO; SILVA, IVAN; FELINTO, MARIA C.; TEOTONIO, ERCULES; MALTA, OSCAR; BRITO, HERMI. The influence of the odd-even effect of aliphatic dicarboxylate ligands on the photoluminescent properties of europium complexes. In: PREQUEL SYMPOSIUM ON ADVANCED TECHNOLOGIES AND MATERIALS, October 13-15, 2020, Online. Abstract... 2020. Disponível em: http://repositorio.ipen.br/handle/123456789/32677. Acesso em: $DATA.

Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.

Como referenciar este item

Abstract: Nanomaterials doped with rare earth ions have attracted great attention due to their unusual optical and electronic properties which leads these materials to be looked at as potential materials for application in the fields of high performance luminescent devices, lighting, magnets, catalysts, medical diagnostics, markers biological luminescent, etc. The advantages of using lanthanide ions as luminescent markers are numerous: it is a safe, low cost method, has higher specificity, the tests are more sensitive and the luminescence can be measured quickly, with a high degree of sensitivity and accuracy. [1-3] Among the methods used in obtaining nanocrystals can be mentioned: coprecipitation, sol-gel, microemulsion, microwave, polymer precursor, among others. In recent years, the polymer precursor (Pechini) and combustion methods are being used with greater emphasis due to the race to obtain nanoparticulate compounds, with homogeneous morphology in order to improve the performance of luminescent materials with application in nanotechnology. The Ba(1-x)WO4:xEu3+ powders were synthesized using the Pechini method, where the solutions of the salts of the Ba2+ and Eu3+ percussors in the form of NO3 ions. The 1: 4 citric acid and ethylene glycol solutions were added in the form of heat and heat to form a polymer resin, the pH being adjusted to 7 with ammonium hydroxide so that a brown, transparent resin . This resin was heated at 300°C for 2 hours, resulting in a black mass, which was prepared for the preparation of the precursor in powder form. The precursor was calcined at a preset temperature of 900°C for the production of barium tungstate.

MOREIRA, R.P.; FELINTO, M.C.; BRITO, H.F. Synthesis of tungstates nanoparticles with luminescent properties. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020. Disponível em: http://repositorio.ipen.br/handle/123456789/31881. Acesso em: $DATA.

Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.

Como referenciar este item

Abstract: Protein-based nanoparticles have been proved a promissing alternative for the loading and delivery of chemotherapeutic agents, radiopharmaceutics and other drugs of interests, constituting a less toxic therapeutic option due to its biocompatibility and low or null side effects. The use of radiation to crosslink or form covalent bonds enables the controll of the crosslinking process, without the need for crosslinking agents, as well as provides sterilizations simultaneously, withouth generating toxic compounds or products. The present work targets the synthesis an purification of albumin-based nanocarrier crosslinked by gamma radiation for biomedical applications. For such purpose, albumin nanoparticles were synthesized using BSA at 20% ethanol (v/v) in 50 mM phosphate buffer on an ice bath prior to and after irradiation. Samples were exposed to gamma radiation at a minimun absrobed dose of 10 kGy at 5kGy.h-1 and purified using a SuperdexTM 200 Increase 10/300GL for isolating the crosslinked protein (high molecular weight) from the native BSA. After the purification, the fractions were characterized by electrophoresis, Uv, fluorescence and dynamic light scaterring. The nanoparticles were obtained in the range of 25-40 nm and purified into fractions of high molecular weight and the native ones. The high molecular weight fractions presented increased bityrosine levels if compared to the fraction corresponded to the native BSA. The yields of nanoparticle formation remains to be determined, but our results provided a clear evidence of the formation of radiation-crosslinked BSA nanoparticles and the role of bityrosine in the nanoparticle assembly.

RIELLO, F.N.; VARCA, G.H.; LIMA, C.S.; FREITAS, L.F.; FERREIRA, A.H.; LUGAO, A.B. Synthesis and purification of albumin-based nanoparticles crosslinked by radiation. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020. Disponível em: http://repositorio.ipen.br/handle/123456789/31873. Acesso em: $DATA.

Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.

Como referenciar este item

Abstract: Rare earths have improved their importance owing to optical properties not only in the research area, but also in industrial and technological areas. Due to it higher luminescent intensity, Eu3+ complexes are among the most studied rare earth complexes that present luminescence, due to the structures of their energy levels. Combination with high molar absorptive ligands can promote a high emission of the Eu3+ ions. The present study concerns to luminescent doped polymers from methyl polymethacrylate (PMMA) used as a matrix for the development of luminescent films. The rare earth complex [Eu (tta)3 (H2O)2] was synthesized and used as a precursor for the synthesis of the secondary complex [Eu (tta) 3 (TPPO)2]. Silver nanoparticles synthesized and encapsulated in luminescent polymeric system showed distint luminescence behavior in the presence of those nanoparticles. After synthesis, the films were characterized. Investigation of the thermal behavior used differential exploratory calorimetry (DSC) and thermogravimetric analysis (TGA) techiniques. The characteristic fine emissions of the metal ion from the 5D0 ? 7FJ transitions (J = 0-4) indicated the incorporation of Eu3+ ions from both complexes in the matrix. The films showed the increase of the luminescence intensification of secondary complex in relation to the precursor complex. When encapsulating the silver nanoparticles to the luminescent systems, the luminescence intensity of these materials increased under conditions of low concentrations of the complex.

PARRA, D.F.; LIMA, V.d.; LUGAO, A.B.; COTRIM, M.H. Synthesis and characterization of encapsulation of silver nanoparticles with luminescent methyl polymethacrylate (PMMA). In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020. Disponível em: http://repositorio.ipen.br/handle/123456789/31893. Acesso em: $DATA.

Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.

Como referenciar este item

Abstract: Conventional food packaging is in general, not recyclable, based on practically undegradable petroleum-derived polymers, and consequently not selectively collected. Concerns over their environmental impact and sustainability issues posed by their production and disposal and trends have increased interest and driven the effort to generate biobased and biodegradable packaging to replace or complement the conventional ones. The aims of this work are to investigate the development of biocomposite films composed of biodegradable polylactic acid(PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blend and cellulose nanowhiskers extracted from agro-waste and evaluate their potential use in sustainable food packaging application. Biocomposite films based on biodegradable PLA/PBAT blend containing 1-2 wt. % of cellulose nanowhiskers extracted from agro-waste were prepared by melt extrusion, using a twin-screw extruder machine and blown extrusion process. To evaluate the potential use in food packaging applications, the cellulose nanowhiskers' content on the morphological, mechanical and thermal properties of the as obtained biocomposite films has been assessed. In addition, cellulose nanowhiskers were characterized by TEM, DLS, XRD, and TG. The results showed that cellulose nanowhiskers addition leads to an important increase in thermal degradation temperature, melting enthalpy and tensile properties of biocomposite films. The increases in the melting enthalpy can be attributed to the increase in the crystallinity of PBAT/PLA biocomposite as a result of cellulose nanowhiskers' addition. Morphology and thermal tests were related to the properties of the films and confirmed that cellulose nanowhiskers were homogeneously dispersed into the matrix. Based on the results, this research demonstrated that the use of biodegradable polymer blend and cellulose nanowhiskers extracted from agro-waste represents an interesting alternative for the production of flexible biocomposite films for sustainable food packaging applications and for the development of eco-friendly technologies.

MOURA, E.A.; SANTOS, B.S.; OLIVEIRA, R.R.; RODRIGUES, R.C. Synergistic effect of polylactic acid(PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blend and cellulose nanowhiskers for sustainable packaging applications. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020. Disponível em: http://repositorio.ipen.br/handle/123456789/31897. Acesso em: $DATA.

Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.

Como referenciar este item

Abstract: The ion exchange / sorption method is one of the most popular and attractive methods used to treat effluents containing heavy metals. The peculiar chemical characteristics, associated to the nanoscale of the structural network with the presence of natural nanotubes, as is the case of paligorsquita, makes it a potential candidate to meet the requirements of high sensitivity and selectivity in the extraction of heavy ions in wastewater. In the process of developing materials with sorption properties for the incorporation and subsequent immobilization of heavy ions in the same matrix, the most important steps are the generation of active sites, together with increased specific surface area. The parameters and conditions for the activation process of the natural Palygorskite nanotubes aiming to the sorption and immobilization of nickel ions present in wastewater from industrial activities were determined. Paligoskite from Piaui State Brazil, was used as raw material. The characterized and the acid activation process were selected for this development. Subsequent heat treatments were carefully selected conditions by thermal analysis (ATD/TG) to avoid collapse of the nanotubes. The results obtained of maximum sorption capacity for nickel on activated natural nanotubes were very promising. Structural folding observed in the clay may surely important contribution for the heavy metal immobilization processes. Finally, the optimization of the acid activation process is fundamental to improve the sorption’s capacities in solid-liquid medium for extraction specifics metals by activated natural nanotubes.

MELLO-CASTANHO, S.; PARRA SILVA, J.; YAMAGATA, C. Surface activation of Palygoskite nanotubes for wastewater treatment. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020. Disponível em: http://repositorio.ipen.br/handle/123456789/31903. Acesso em: $DATA.

Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.

Como referenciar este item

Abstract: There are several protocols for the synthesis of gold nanoparticles, and lately there is a trend for green methods in order to minimize the environmental impacts. The reduction of gold salts by epigallocatechin 3 gallate, for instance, generates stable and uniform nanoparticles without the use of toxic compounds, and so does the radiolytic synthesis protocol. For medical purposes, proteins like albumin and papain are useful coating agents, providing a better biological effectiveness. Here we present a comparison of different synthetic and protein coating protocols for gold nanoparticles regarding their stability in different NaCl concentrations and pH, aiming for the development of nanoparticles that are able to be administered in physiologic solutions to patients. The nanoparticles were synthesized via EGCG (2 mg mL 1) reduction of gold salt (5 mmol L 1) in phosphate buffer pH 7.0. Those nanoparticles were coated or not with albumin or papain (1 mg mL 1) using mercaptopropionic acid. Other protein coated gold nanoparticles were synthesized radiolytically by mixing 5 mmol L 1 NaAuCl4 with 1 mg mL 1 bovine serum albumin (BSA) or papain and 0.1 mol L 1 tert butanol. The solutions were irradiated with 10 kGy (60Co source, 5 kGy h 1) and the resulting suspensions were stored until use. The suspensions were added in 96 well plates to solutions with different pH and NaCl concentrations, and their absorption spectra were taken periodically to verify their stability. It was observed that BSA gold nanoparticles synthesized by both protocols were stable in concentrations of NaCl varying from 0.1% to 14.4% up to 72h. The papain gold nanoparticles synthesized by both protocols were stable in concentrations of NaCl varying from 0.1% to 14.4% up to 48h, but in 72h there was evidence of instability in the lowest and highest NaCl concentrations. The nanoparticles coated just with EGCG (without proteins) were stable in all NaCl concentrations and times, except in the highest concentration after 72h. Regarding the pH, BSA gold nanoparticles and papain gold nanoparticles synthesized radiolytically, as well as EGCG gold nanoparticles were stable at least in pH varying from 5 to 11, in all times analyzed. In conclusion, all the nanoparticles tested are able to be administered to patients in physiological solutions, which have pH around 7.4 and NaCl concentrations around 0.9%, without the risk of aggregation and loss of biological activity.

FREITAS, L.F.; CRUZ, C.C. da; BATISTA, J.G.; VARCA, G.H.; LUGAO, A.B.; PIRES, M.A. Stability of gold nanoparticles in different ionic concentrations and pH: a comparison among synthetic protocols. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020. Disponível em: http://repositorio.ipen.br/handle/123456789/31868. Acesso em: $DATA.

Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.

Como referenciar este item