Landfill leachate is a global problem that has attracted considerable attention from researchers in different areas. It is crucial to develop optimized treatment strategies for landfill leachate, given the need to minimize or eliminate... more
Landfill leachate is a global problem that has attracted considerable attention from researchers in different areas. It is crucial to develop optimized treatment strategies for landfill leachate, given the need to minimize or eliminate negative environmental impacts resulting from the inadequate disposal of solid waste, as determined by legislation. Landfill leachate is primarily composed of humic substances, which may associate with other toxic molecules and are recalcitrant to the conventional treatments used in Brazil. This study assessed the photocatalytic degradation of carbonaceous materials in leachate collected from the Cachoeira Paulista municipal landfill, São Paulo State, Brazil. Sunlight was used as energy source without additional light inputs. Experiments were carried out in a thin-film fixed-bed reactor, using metal plates coated with paints formulated for this purpose. Paints had a low additives loading, including that of photocatalysts. We investigated the photocata...
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The treatment of leachate from landfills is an important issue from an environmental point of view, as such leachates are classified as hazardous materials. This issue has received the attention of researchers in several regions of the... more
The treatment of leachate from landfills is an important issue from an environmental point of view, as such leachates are classified as hazardous materials. This issue has received the attention of researchers in several regions of the world, especially in developing countries. Conventional biological treatment of leachate from mature landfills has not yielded consistent results, mainly because of the recalcitrance of humic substances. Little is known about the kinetic complexity of leachate treatment by oxidative methods, representing a barrier to process scale-up from benchtop experiments. In this study, a modeling approach was applied to describe the photodegradation of humic substances in a plug flow reactor connected to a stirred tank. The kinetic model provided an R2 of 0.974. Rate constants for humic acids (HA) and fulvic acids + humans (FAH) were 2.96 and 1.03 × 10− 3 min− 1, respectively. Statistical models for the degradation reaction had R2 values of 0.96 for HA and 0.99 ...
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The aim of this work is to present radar cross section (RCS) measurements of a panel constituted of a flat aluminum plate with and without radar absorbing materials (RAM) type thin rubber sheets, in the range of 8 – 12 GHz. Two different... more
The aim of this work is to present radar cross section (RCS) measurements of a panel constituted of a flat aluminum plate with and without radar absorbing materials (RAM) type thin rubber sheets, in the range of 8 – 12 GHz. Two different loads were evaluated in the RAM formulation: 1. Magnetic (ferrites - MnZn, NiZn and MgZn based), and 2. Dielectric (conducting polymers - polyaniline based). The measurements
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This article aims to demonstrate the gains obtained with the change of process flow between the compaction and sintering in the powder metallurgy process, aiming to eliminate the stock in process between these operations. The rationale... more
This article aims to demonstrate the gains obtained with the change of process flow between the compaction and sintering in the powder metallurgy process, aiming to eliminate the stock in process between these operations. The rationale used for changing the flow was structured in the use of the WCM (World Class Manufacturing) methodology with the integration of the LCS Pillars (Logistic and Customer Service) managed by logistics and EEM (Early Equipment Management, managed by industrial engineering. In order to demonstrate the results of the integration between the two pillars, a case study was carried out in an industry in the automotive sector located in ABC São Paulo, where the results obtained prove the expected improvements with the elimination of the WIP stock between the two operation. The present work demonstrates the problems related to this stock, how they were solved, and the results obtained.
The aim of present work is to present the synthesis of a PAA which will be used as interphase in the high performance thermoplastic composites manufacturing. For the composites manufacturing, the PAA is solubilized in a base and used in... more
The aim of present work is to present the synthesis of a PAA which will be used as interphase in the high performance thermoplastic composites manufacturing. For the composites manufacturing, the PAA is solubilized in a base and used in manufacture of suspension prepregging technique. The PAA studied was synthetized by using the BTDA dianhydride and Bis-P diamine reagents. In the present work, are presented the results by DSC (differential scanning calorimetry), TGA (thermogravimetric) and SEM (scanning electron microscopy) analyses that confirmed the synthesis. The DSC and TGA techniques indicated the glass transition (~248°C) and decomposition (~401°C) temperatures. These results show that the PAA/PI of type BTDA/Bis-P can be used as interphase in preparing of thermoplastic composites under broad window processing temperature.
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ABSTRACT
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The efficiency of recently developed RAM (Radar Absorbing Materials) based on conducting polymers in sheet texture has been investigated by X-band (8 to 12 GHz) scattering measurements and, also by determination of their complex... more
The efficiency of recently developed RAM (Radar Absorbing Materials) based on conducting polymers in sheet texture has been investigated by X-band (8 to 12 GHz) scattering measurements and, also by determination of their complex dielectric constant by a waveguide method. This paper presents the experimental methodology used to characterize RAM based on a conducting polymer called polyaniline. The correlation between
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... of Carbon Fiber/PEI Composites Based on Aqueous Polymeric Suspension of Polyimide Liliana Burakowski Nohara1, 2, Geraldo Maurício Cândido2 ... and secondary aircraft structure, radomes and stealth panels for military use and snow... more
... of Carbon Fiber/PEI Composites Based on Aqueous Polymeric Suspension of Polyimide Liliana Burakowski Nohara1, 2, Geraldo Maurício Cândido2 ... and secondary aircraft structure, radomes and stealth panels for military use and snow boards (Offringa, 1996; Jenkins, 1999). ...
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The efficiency of recently developed RAM (Radar Absorbing Materials) based on conducting polymers in sheet texture has been investigated by X-band (8 to 12 GHz) scattering measurements and, also by determination of their complex... more
The efficiency of recently developed RAM (Radar Absorbing Materials) based on conducting polymers in sheet texture has been investigated by X-band (8 to 12 GHz) scattering measurements and, also by determination of their complex dielectric constant by a waveguide method. This paper presents the experimental methodology used to characterize RAM based on a conducting polymer called polyaniline. The correlation between
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This work is aimed at presenting the synthesis of a poly (amic acid) (PAA) to be used as interphase precursor in the manufacturing of high performance thermoplastic composites. Thermoplastic composites comprising a rigid reinforcement and... more
This work is aimed at presenting the synthesis of a poly (amic acid) (PAA) to be used as interphase precursor in the manufacturing of high performance thermoplastic composites. Thermoplastic composites comprising a rigid reinforcement and a ductile matrix have their mechanical properties strongly dependent on the load transfer mechanism between the reinforcement and matrix. For this reason, the interface/interphase region
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Physical Optics (PO) is used to calculate Radar Cross Section (RCS) of flat plate and dihedral corner reflectors. The numerical results obtained via simulation are used to compare the RCS measured for these targets recovered and... more
Physical Optics (PO) is used to calculate Radar Cross Section (RCS) of flat plate and dihedral corner reflectors. The numerical results obtained via simulation are used to compare the RCS measured for these targets recovered and non-recovered with Radar Absorbing Materials (RAM). All simulations and experiments are effectuated in a frequency of 10 GHz. Experimental measurements using Radar Cross Section (RCS) confirm the accuracy of the analytical calculation for flat plate and dihedral corner reflectors. The RAM performance is analyzed for each target separately. The RAM used to recover the flat plate and dihedral corner was developed at Divisao de Materiais IAE/CTA.
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Due to the great need for reducing production costs, productivity increasing quality improvement of products, the study had its start drafting surface treatment of dies process development, where the first step was a market study looking... more
Due to the great need for reducing production costs, productivity increasing quality improvement of products, the study had its start drafting surface treatment of dies process development, where the first step was a market study looking for the treatment types and their applications. These treatments are intended to stabilize the production process so that there are no variations on the production and increasing the useful life of dies and their appropriate tools. It was determined through analysis, that the parts had problems in dies drawing which influenced on productivity, quality and cost. It had been realized that those parts had similar problems and the treatments could generally minimize such problems. The following step was to apply the treatment of dies and tools, and then realized that the results achieved certain goals, managing to stabilize the stamping process of those parts.
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... I Departamento de Engenharia Aeronáutica e Mecânica, Instituto Tecnológico de Aeronáutica -ITA, Centro Técnico Aeroespacial, 12228-904 São José dos Campos - SP, Brazil II Departamento de Física, Instituto Tecnológico de Aeronáutica -... more
... I Departamento de Engenharia Aeronáutica e Mecânica, Instituto Tecnológico de Aeronáutica -ITA, Centro Técnico Aeroespacial, 12228-904 São José dos Campos - SP, Brazil II Departamento de Física, Instituto Tecnológico de Aeronáutica - ITA, Centro Técnico Aeroespacial ...
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ABSTRACT The use of polyamic acid (PAA) precursor as interphase in polymer composites is one of the many applications of polyimides (PIs). In this work, composites based on poly (ether-ether-ketone)(PEEK) and carbon fibers were prepared... more
ABSTRACT The use of polyamic acid (PAA) precursor as interphase in polymer composites is one of the many applications of polyimides (PIs). In this work, composites based on poly (ether-ether-ketone)(PEEK) and carbon fibers were prepared using two manufacturing ...
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ABSTRACT Resumo Os Materiais Absorvedores de Radiação Eletromagnética (MARE) são obtidos com base no processamento de matrizes poliméricas aditadas com partículas específicas ao uso de absorvedor. Este trabalho tem por objetivo... more
ABSTRACT Resumo Os Materiais Absorvedores de Radiação Eletromagnética (MARE) são obtidos com base no processamento de matrizes poliméricas aditadas com partículas específicas ao uso de absorvedor. Este trabalho tem por objetivo determinar o coeficiente de reflexão em guia de ondas (S 11 com placa metálica) de MARE à base de ferritas de MnZn, na faixa de freqüências de 8-12 GHz, tendo como variável a concentração, em massa, da ferrita em uma matriz de resina epóxi. Foram obtidas micrografias da superfície das amostras, avaliando-se a dispersão da ferrita na matriz de resina epóxi. Os resultados obtidos mostram a influência do aumento da atenuação do sinal incidente no material em função do aumento da concentração da ferrita de MnZn. Palavras-chaves Material absorvedor de radiação eletromagnética, caracterização eletromagnética, guia de ondas, ferrita de microondas.