RESUMO RACIONAL: O tumor sólido pseudopapilar do pâncreas tem sido relatado na literatura com mais frequência nas últimas duas décadas. A cirurgia continua sendo o tratamento indicado, sendo o fígado o local mais frequente de metástases. OBJETIVOS: Apresentar a opção de tratamento cirúrgico de paciente feminino, 18 anos, com lesão sólida no corpo e cauda do pâncreas associada a lesões metastáticas em ambos os lobos hepáticos. MÉTODOS: Dois procedimentos cirúrgicos foram agendados. No primeiro procedimento foi realizada pancreatectomia corpo-caudal com esplenectomia, associada à ressecção de 3 lesões do lobo esquerdo do fígado. A hepatectomia direita foi realizada seis meses após, evoluindo sem complicações. RESULTADOS: O paciente continua sem queixas clínicas no último retorno, e a ressonância magnética do abdomem realizada 28 meses após o segundo procedimento não mostra lesões hepáticas ou na cavidade abdominal. CONCLUSÕES: O conhecimento do comportamento biológico dos tumores, a evolução e os riscos de recidiva, permitem a indicação de técnicas cirúrgicas mais racionais e que melhor beneficiam os pacientes.

ABSTRACT BACKGROUND: Solid pseudopapillary tumor of the pancreas has been frequently reported in the past two decades. Surgery remains the treatment of choice, with the liver being the most frequent site of metastases. AIMS: The study aimed to present an option of surgical treatment for an 18-year-old female patient with a solid lesion in the body and tail of the pancreas associated with metastatic lesions in both hepatic lobes. METHODS: Two surgical procedures were scheduled. In the first procedure, body-caudal pancreatectomy with splenectomy was performed, associated with the resection of three lesions of the liver's left lobe. A right hepatectomy was performed 6 months later, progressing without complications. RESULTS: The patient continues without clinical complaints on the last return, and abdominal magnetic resonance performed 28 months after the second procedure does not show liver or abdominal cavity lesions. CONCLUSIONS: The knowledge on the biological behavior of tumors, evolution, and recurrence risks allows the indication of more rational surgical techniques that best benefit patients.

RESUMO - RACIONAL: Apesar da recomendação atual que o cistoadenoma seroso deva ser tratado de forma conservadora, significativa parte dos pacientes com essa condição ainda é operada por dúvida diagnóstica. OBJETIVO: Analisar causas da baixa acurácia diagnóstica do cistoadenoma seroso. MÉTODOS: Estudo retrospectivo de portadores de cistoadenoma seroso de um banco de dados de dois ambulatórios de cirurgia hepatopancreaticobiliar entre 2006 e 2020. Foram incluídos pacientes com lesões típicas de cistoadenoma seroso aos exames de imagem (tomografia computadorizada, ressonância magnética e ecoendoscopia) e pacientes que o anatomopatológico confirmasse esse diagnóstico. RESULTADOS: 27 pacientes foram incluídos. 85,18% eram do sexo feminino. A idade média foi de 63,4 anos. Apenas um apresentava sintomas típicos de pancreatite. A Ressonância magnética foi o exame mais realizado (62,9%). A lesão era única em 88,9% e o tamanho médio foi 4 cm. O aspecto típico microcístico foi encontrado em 66,6% dos casos, os demais foram considerados atípicos. A ecoendoscopia foi realizada em 29,6%. O valor médio de antígeno carcinoembrionário nos pacientes submetidos à punção do cisto foi de 198,25 ng/mL. O tratamento cirúrgico foi realizado em 10 casos (37%). Em 7, a causa cirúrgica foi a suspeita do cistoadenoma mucinoso mediante identificação de lesões atípicas (unilocular com ou sem septos e macrocística). Em 2, a suspeita de neoplasia papilar intraductal mucinosa com “fatores preocupantes” foi a indicação cirúrgica. O último foi submetido à cirurgia por lesão de aspecto sólido e suspeita de câncer. O índice de complicações > ou = Clavien-Dindo 2 foi 30%, o índice de fístula pancreática clinicamente relevante (B e C) foi 30%. A mortalidade foi nula. CONCLUSÃO: A apresentação morfológica atípica do cistoadenoma seroso, particularmente lesões uniloculares e macrocísticas, é a principal responsável pela indicação cirúrgica. Apenas a implementação de novos, eficientes e reprodutíveis métodos diagnósticos poderá reduzir o número de cirurgias desnecessárias nesses pacientes.

ABSTRACT - BACKGROUND: Many patients with serous cystadenoma of the pancreas (SCP) underwent surgery due to diagnostic doubt. AIM: The aim of this study was to analyze the causes of low accuracy in diagnosing SCP. METHODS: This is a retrospective study of patients with SCP from a database of two hepatopancreatic biliary surgery outpatient clinics between 2006 and 2020. Patients with typical SCP lesions in imaging exams (e.g., tomography, magnetic resonance imaging [MRI], and endoscopic ultrasound [EUS]) and patients whose pathological testing confirmed this diagnosis were included. RESULTS: A total of 27 patients were included in this study. Most patients were women (85.18%), and the mean age was 63.4 years. Only one patient had typical pancreatitis symptoms. MRI was the most performed method (62.9%). The lesion was single in 88.9%, and the average size was 4 cm. The typical microcystic aspect was found in 66.6%. EUS was performed in 29.6% of cases. The mean carcinoembryonic antigen value in patients undergoing cyst puncture was 198.25 ng/mL. Surgical treatment was performed in 10 cases (37%). The cause of surgery in seven of these cases was due to a suspicion of mucinous cystadenoma based on an identification of atypical lesions (unilocular with or without septa and macrocystic) in imaging exams. A suspicion of intraductal papillary mucinous neoplasm with “worrying factors” was the indication for surgery in two cases. The last case underwent surgical treatment for a solid-looking lesion which was suspected of cancer. The complication rate ≥Clavien-Dindo 2 was 30%, and the clinically relevant pancreatic fistula rate (B and C) was 30%. Mortality was nil. CONCLUSION: The atypical morphological presentation of SCP, particularly unilocular and macrocystic lesions, is the main indication for surgery. Only the implementation of new, efficient, and reproducible diagnostic methods can reduce the number of unnecessary surgeries among these patients.

ABSTRACT Composite materials using vegetal fibers and industrial waste are being applied in different areas and structures, requiring, more and more, researches that highlight their characteristics. In this context, the study of manufacturing techniques becomes increasingly necessary in order to use the appropriate tools and obtain the best conditions of the materials. Thus, this article demonstrates the behavior of the materials, which used the polyester resin with ground paper residue to generate the two composites studied in this paper, Polyester/smaller paper (PO/ PME) and Polyester/large paper (PO/PMA). These two materials were molded by hot compression and subjected to manufacturing processes. Joinery equipment were chosen for the experimentation of cutting, drilling, screw insertion and sanding to analyze the performance of these composite materials. As a general result, it can be observed that the composites maintained their physical integrity, because the particles of the load remained well anchored in the matrix in the two composite materials tested, giving the finish an aspect without damages, cracks or imperfections after the operations. Therefore, it is concluded that the materials created can be submitted to the manufacturing techniques evaluated in this article, reinforcing previous studies that suggest its use in the development of products such as furniture, table tops, decorative objects and others. Thus, this study contributes to Designer has knowledge of the potential of the material and make the best use of it.

RESUMO As placas de circuito impresso (PCIs) são as partes mais valiosas dos resíduos eletrônicos, pois possuem uma considerável quantidade de metais com potencial de recuperação. Processos de reciclagem com o intuito de recuperar metais de PCIs têm despertado interesse ultimamente. Contudo, uma fração destes resíduos não é completamente aproveitada e tem destino incerto, como ocorre para a fração não-metálica e o pó gerados durante os processos de recuperação de metais. O foco deste estudo foi o emprego do pó gerado nos processos de cominuição mecânica, separação granulométrica, magnética e eletrostática de PCIs controladoras e indicadoras de temperatura de câmaras frias, para obter compósitos de matriz de polipropileno (PP) com diferentes teores de pó de PCIs, 5, 10 e 20% em massa. Os materiais foram pesados, misturados, moldados por injeção e posteriormente caracterizados por ensaios de tração, dureza Shore D, espectroscopia de infravermelho, análise termogravimétrica e microscopia eletrônica de varredura. Os resultados dos ensaios de tração e dureza indicaram propriedades levemente superiores às do PP puro, exceto para a deformação na ruptura, que foi reduzido em até 2,7 vezes para a amostra com 20% de resíduo. O desenvolvimento de compósitos utilizando o pó de PCIs se mostrou viável em aplicações onde as propriedades resistência à tração, rigidez e dureza são determinantes, mesmo para um elevado teor de resíduo (20%) agregado.

ABSTRACT Printed Circuit Boards (PCBs) are the most valuable parts of e-waste because they have a considerable amount of metals with recovery potential. Recycling processes aimed at recovering metals from PCBs have aroused great interest recently. However, there is a fraction of this waste that is not utilized and has uncertain destination, e.g. the non-metallic fraction and the dust generated during metal recovery processes. The focus of this study was to employ the powder generated in the mechanical comminution, granulometric, magnetic and electrostatic separation processes of controller and temperature indicator PCBs of cold rooms to obtain polypropylene (PP) matrix composites with distinct PCBs powder content, 5, 10 and 20% in weight. The sample was collected during the mechanical comminution processes. The materials were weighed, mixed, injection molded and later characterized using tensile tests, Shore D hardness, infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. Results of the tensile and hardness tests showed properties slightly superior to pure PP, except for strain at break, which was reduced up to 2.7 times for the sample with 20% of residue. In all, the development of composites using the powder of PCBs was considered feasible for applications where tensile strength, stiffness and hardness are important, even for a large amount of residue added (20%).

RESUMO O poliestireno expandido (EPS) é um polímero reciclável amplamente utilizado na fabricação de embalagens para isolamento acústico, proteção de bens de consumo duráveis e na indústria da construção civil. O PS é facilmente reciclável com o aumento da temperatura, podendo dar origem a novos materiais. Entretanto suas propriedades térmicas podem ser afetadas, principalmente se acrescidos de fibras naturais. Diante desse contexto, esse trabalho tem como objetivo estudar as propriedades térmicas dos compósitos de poliestireno reciclado reforçados com fibra de celulose do bagaço de cana-de-açúcar. Os compósitos de PS reciclados contendo 10 e 20% (m/m) de celulose de bagaço foram obtidos por extrusão e caracterizados por análise térmica: Análise Termogravimétrica (TGA), Calorimetria Exploratória Diferencial (DSC), Análise Dinâmico-Mecânica (DMA) e Temperatura de Deflexão Térmica (HDT). Os resultados mostraram que as fibras ricas em lignina residual atuaram como reforço melhorando a rigidez do material com a adição das fibras, bem como promoveram o aumento da temperatura de deflexão térmica. Já a estabilidade térmica dos compósitos é intermediária entre a fibra e matriz, diminuindo com o aumento do teor de fibras. Portanto, conclui-se que a utilização de EPS como matriz na obtenção de compósitos reforçados com fibras naturais é viável e sugere o uso deste resíduo como uma excelente alternativa para o setor de reciclagem.

ABSTRACT Expanded polystyrene (EPS) is a recyclable polymer widely used in the manufacture of packaging for acoustic insulation, protection of durable consumer goods and in the construction industry. The PS is easily recyclable with increasing temperature, giving new materials. However, thermal properties can be affected, mainly if added of natural fibers. In this context, this work objective to study the thermal properties of recycled polystyrene composites reinforced with cellulose fibers from sugarcane bagasse. The recycled composites of PS reinforced 10 and 20 wt% cellulose bagasse were obtained by extrusion, and characterized by thermal analysis thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and heat deflection temperature (HDT). The results showed that the fibers rich in residual lignin act as reinforcement improving the stiffness of the material with the addition of the fibers, as well as promoted the increase of the heat deflection temperature for the composites. The thermal stability of the composites is intermediate between the fiber and matrix, decreasing with the increase of fibers content. Therefore, it is concluded that the use of EPS as a matrix in the obtainment composites reinforced with natural fibers is viable and suggest the use of this residue as an excellent alternative for the recycling industry.

Abstract Carbon Fiber Reinforced Polymer (CFRP) cables, due to their outstanding performance in terms of specific stiffness and strength, are usually found in civil construction applications and, more recently, in the Oil & Gas sector. However, experimental data and theoretical solutions for these cables are very limited. On the contrary, several theoretical and numerical approaches are available for isotropic cables (metallic wire ropes), some of them with severe simplifications, nonetheless showing good agreement with experimental data. In this study, experimental tensile results for 1×7 CRFP cables were compared to a simplified analytical model (assumed transversally isotropic) and to a 3D finite element model incorporating the experimental uncertainty in important input parameters: longitudinal elastic modulus, Poisson’s ratio, static friction coefficient and ultimate tensile strain. The average experimental breaking load of the cable was 190.25 kN (coefficient of variation of 1.74%) and the agreement with the numerical model predictions were good, with an average-value deviation of –1.15%, which is lower than the experimental variations. The simplified analytical model yielded a discrepancy above 10%, indicating that it needs further refinement although much less time consuming than the numerical model. These conclusions were corroborated by statistical analyses (i.e. Kruskal–Wallis and Mann-Whitney).

This work addresses the use of piassava fibers (PF) as reinforcement for recovered polypropylene (PPr) in the manufacturing of composites. The composites were molded with variable amounts of PF (10, 20 and 30 wt%), with and without maleic anhydride functionalized polypropylene (MAPP) (10 wt%) as compatibilizer. The composites were characterized using mechanical tests (flexural, tensile, impact and hardness), thermal analyses (thermogravimetric analysis and differential scanning calorimetry), along with evaluations of heat deflection temperature, melting flow index, density and morphology. Tensile and flexural strength of composites increased with PF content, but impact strength decreased, since the material became stiffer. The use of MAPP in the formulations yielded superior properties, showing good fiber/matrix interaction. In all, the use of PF as reinforcement in PPr was considered an interesting way of reducing solid waste and to reinforce plastics, being a possible alternative for the substitution of wood in WPC composites.

ABSTRACT Resin Transfer Molding (RTM) process is commonly used to produce high quality polymeric composites with simple or complex geometries in small to large sizes. In RTM process a preformed reinforcement is positioned inside the mold cavity. This dry reinforcement is actually a fibrous porous media whereby resin will flow. The mold is then closed and resin is injected. After complete impregnation of the reinforcement, resin cure process takes place. Numerical simulation is a very useful tool for mold design and process optimization, however resin and reinforced medium physical properties must be precisely determined. Medium permeability is probably the most important and most difficult parameter to be evaluated. In this work it is proposed a numerical/experimental methodology to determine transverse permeability in reinforcements used within RTM process. PAM-RTM software was chosen to simulate resin flow through the reinforced medium. Proposed methodology uses the inverse parameter estimation method to calculate the unknown permeability. Newton-Raphson method was used to solve the associated algebraic equation system, on which PAM-RTM software is used to calculate resin injection times. Results have shown that with previous knowledge (taken from literature or obtained experimentally) of the in-plane permeabilities ( Kxx and Kyy ), physical properties of the resin (ρ, µ), medium porosity (ε) and total filling time (t) it is possible to estimate transverse permeability in thick pieces. It was also performed a numerical study about the influence of transverse permeability in resin flow inside the mold. This study predicted several possible problems that may occur when transverse permeability is much smaller than in-plane permeabilities. Finally, it is possible to state that mold design and proper fibrous reinforcement choice can be optimized when numerical techniques are used.

ABSTRACT Concerns for the environment are recurrent in our society, and research on low impact materials such as those produced from waste is an alternative. This work is based on the reuse of scrap paper and rice hulls aiming to increase the life cycle of these waste products and to find better destination. Composites with a volumetric filler content (dispersed phase) of 80% were produced via compression molding using polyurethane (PU) based on castor oil or polyester resin as matrix, in four distinct families: polyester/rice hulls, PU/rice hulls, polyester/paper and PU/paper. The following tests were performed: water sorption, contact angle, hardness, impact and tensile testing. Scanning electron microscopy (SEM) was used for fracture morphology study. Basic visual analysis showed greater void content for the rice hull composites, making them less aesthetically appealing compared to paper. It was observed in the case of PU matrix the filler greatly influenced the rigidity since this pure material was more flexible compared to pure polyester. Filler incorporation decreased tensile strength of the polyester matrix but significantly increased that of the PU matrix.

This study focuses on the use of waste cotton fiber from the textile industry to produce composites with unsaturated polyester and to evaluate the performance of glass (G) / cotton (C) fiber laminates, particularly their mechanical and dynamic mechanical properties. Distinct stacking sequences were studied but the overall fiber content was kept constant. In general, hybrid laminates exhibited intermediate mechanical properties compared to those of the pure laminates, and optimum performance was obtained when the glass fiber mats were placed on the surfaces of the composite. Furthermore, some hybrid laminates exhibited superior dynamic mechanical performance, even compared to the pure glass laminate. Lower tan delta peak height (related to better fiber-matrix interaction) values and higher Tg were reported for the [C/G/ G ¯]s and [G/C/ C ¯]s samples which, together with the [G/C/ G ¯]s sample, exhibited the best results for reinforcement effectiveness and loss modulus peak height. Therefore, it is found possible to partially replace the glass fiber by waste cotton fiber considering that the final product may be optimized for mechanical property, which requires glass fiber at the surface of the laminate, or for dynamic mechanical properties, that allows higher cotton fiber content.

Este trabalho tem por objetivo a busca por técnicas alternativas para diminuir a incidência de vazios em resinas poliméricas e, por consequência, em materiais compósitos. Foram produzidas formulações diferentes utilizando resina epóxi à base de éter diglicidílico do Bisfenol A, endurecedor de poliamina alifática com e sem a adição de diferentes aditivos desaerantes a base de éteres e ésteres modificados. As formulações produzidas foram submetidas a condições extremas de agitação e processamento, sendo posteriormente avaliadas quanto a incidência de bolhas e vazios, densidade, propriedades mecânicas, morfológicas e térmicas. Os resultados foram bastante positivos quanto à diminuição da quantidade e do tamanho de poros pela utilização de técnicas de desgaseificação a vácuo e pelo uso de aditivos desaerantes.

This study aims alternative techniques to reduce the incidence of voids in polymeric resins and in composite materials. Different formulations were prepared using epoxy resin based on bisphenol A diglycidyl ether and an aliphatic polyamine hardener, with and without the addition of different degasing agents based on modified esters and ethers. The formulations produced were subjected to extreme agitation and processing conditions and we evaluated the incidence of bubbles and voids, density, mechanical, morphological and thermal properties. The results were very positive. We observed the decrease in number and size of pores by the use of vacuum degassing techniques and degasing agent additives.

Este trabalho tem como objetivo estudar o efeito de cordonéis de poliéster, poliamida, poliaramida e híbrido poliamida/poliaramida como reforço de elastômeros utilizados na fabricação de mangotes. O comportamento do tubo elastomérico reforçado com cordonéis sob pressão interna foi simulado com análise por elementos finitos (FEA) utilizando-se elementos chamados reinforcement bars. Foram realizados ensaios para se obter as propriedades em tração dos cordonéis para alimentar o modelo. O cordonel de poliaramida apresentou a maior tensão de ruptura, o de poliamida maior deformação na ruptura, e o híbrido apresentou valores intermediários. O critério de falha adotado para o tubo consistiu na análise do nível de carga no cordonel. Foram avaliadas, principalmente, a pressão e a deformação de ruptura do tubo elastomérico simulado frente à variação do ângulo de orientação dos cordonéis. Os resultados mostraram que ângulos próximos a 55° tornam o tubo mais resistente porém menos rígido no sentido longitudinal.

This work investigates the effect of polyamide, polyester, polyaramid and hybrid (polyamide and polyaramid) cords as reinforcement for elastomers used in the production of marine hoses. The behavior of the elastomeric pipe reinforced with these cords under internal pressure was simulated with finite element analysis (FEA) using elements called reinforcement bars. To obtain input data for the model, tensile properties of the cords were evaluated. The polyaramid cord showed the highest ultimate stress, the polyamide the largest elongation at break, and the hybrid cord showed intermediate values. The failure criterion adopted for the pipe consisted of examining the allowable force in the cord. The analyses focused on the variation of pressure and strain at burst of the pipe with the orientation angle of the cords along the elastomeric tube. The results showed that angles close to 55° yielded stronger pipes but less rigid in their longitudinal direction.

In this study, polymer composites using low-density polyethylene (LDPE) and layered hydroxide salts (LHS) were synthesized. The following compositions of LHS were obtained Zn5(OH)8(An-)2/n.yH2O, where A was varied in order to obtain hydrophilic (A = NO3-) or hydrophobic (A = DDS- - dodecyl sulfate or DBS- - dodecyl benzene sulfonate). Synthesis was carried out by co-precipitation in alkaline medium and drying, being followed by characterization via Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy. A variable amount of filler was then incorporated into the LDPE via extrusion, which was then injection molded to obtain specimens for evaluating tensile properties (Young's modulus, tensile strength, strain at break and toughness). For comparison, the sodium salts of the surfactants (NaDDS and NaDBS) were also used as fillers in LDPE. The X-ray diffraction results indicated that the hydrophobic LHS were exfoliated in the polymer matrix, whereas the hydrophilic LHS was only delaminated. In the LDPE composites, melting and crystallization temperatures were nearly constant, along with the crystallinity indexes. The mechanical properties were mainly varied when the organophilic LHS was used. Overall, fillers based on LHS, especially those containing hydrophobic anions, may be interesting alternatives in the production of reinforced thermoplastics.