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Performance evaluation of packing materials in the removal of hydrogen sulphide in gas-phase biofilters: Polyurethane foam, sugarcane bagasse, and coconut fibre

PANTOJA FILHO, Jorge Luis Rodrigues; SADER, Leandro Takano; DAMIANOVIC, Marcia Helena Rissato Zamariolli; FORESTI, Eugenio; SILVA, Edson Luiz
Fonte: ELSEVIER SCIENCE SA Publicador: ELSEVIER SCIENCE SA
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.99%
The main objective of this work was to investigate three packing materials (polyurethane foam, sugar-cane bagasse, and coconut fibre) for biofiltration of a gaseous mixture containing hydrogen sulphide (H(2)S). Mixed cultures were obtained from two sources, aerated submerged biofilters and activated sludge, and were utilised as inoculums. Biofilters reached 100% removal efficiency after two clays of operation. The empty bed residence time was 495 for each of the biofilters. The reactors were operated simultaneously, and the inlet concentrations of H(2)S varied between 184 and 644 ppmv during the long-term continuous operation of the biofilters (100 clays). Average removal efficiencies remained above 99.3%, taking into consideration the entire period of operation. Average elimination capacities reached by the biofilters packed with polyurethane foam, coconut fibre, and sugarcane bagasse were in the range of 17.8-66.6; 18.9-68.8, and 18.7-72.9g m(-3) h(-1), respectively. Finally, we concluded that the packing materials tested in this work are appropriate for the long-term biofiltration of hydrogen sulphide. (C) 2010 Elsevier B.V. All rights reserved.; CNPq; FAPESP; CAPES

Influence of carbon source and inoculum type on anaerobic biomass adhesion on polyurethane foam in reactors fed with acid mine drainage

RODRIGUEZ, Renata P.; ZAIAT, Marcelo
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.84%
This paper analyzes the influence of carbon source and inoculum origin on the dynamics of biomass adhesion to an inert support in anaerobic reactors fed with acid mine drainage. Formic acid, lactic acid and ethanol were used as carbon sources. Two different inocula were evaluated: one taken from an UASB reactor and other from the sediment of a uranium mine. The values of average colonization rates and the maximum biomass concentration (C(max)) were inversely proportional to the number of carbon atoms in each substrate. The highest C(max) value (0.35 g TVS g(-1) foam) was observed with formic acid and anaerobic sludge as inoculum. Maximum colonization rates (v(max)) were strongly influenced by the type of inoculum when ethanol and lactic acid were used. For both carbon sources, the use of mine sediment as inoculum resulted in a v(max) of 0.013 g TVS g(-1) foam day(-1), whereas 0.024 g TVS g(-1) foam day(-1) was achieved with anaerobic sludge. (C) 2011 Elsevier Ltd. All rights reserved.; FAPESP - Fundacao de Amparo a Pesquisa do Estado de Sao Paulo[2006/06122-7]; FAPESP - Fundacao de Amparo a Pesquisa do Estado de Sao Paulo[2008/00388-0]

Espumas poliuretânicas derivadas de óleo de mamona utilizadas na adsorção de bifenilas policloradas (PCBs) presentes em óleo mineral isolante; Polyurethane foam derived from castor oil used in adsorption polychlorinated biphenyls (PCBs) present in mineral insulating oil

Camargo, Marcio Antonio Ferreira
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 24/11/2010 PT
Relevância na Pesquisa
57.03%
Os PCBs, do inglês Polychlorinated Biphenyls (bifenilas policloradas), é o nome genérico dado à classe de compostos organoclorados resultante da reação do grupo bifenila com cloro anidro na presença de catalisador. São tóxicos, persistentes, bioacumulativos e representam o risco de provocar efeitos nocivos à saúde humana e ao meio ambiente. Grandes quantidades de PCBs foram produzidos em vários países entre 1927 e 1977. Nos Estados Unidos a proibição ocorreu em 1977. Utilizados como fluidos dielétricos em transformadores elétricos e capacitores em todo o mundo, comercialmente conhecidos como Ascarel, dentre outras denominações, tais como Aroclor, Pyralene, Clorophen, Inerteen, Asbestol e Kneclor. Devido à alta toxicidade, a produção e comercialização dos PCBs foram proibidas no mundo todo a partir de 1980. No Brasil, transformadores que tiveram o óleo mineral isolante, contaminado por PCBs, estando em uso ou em armazenamento, segundo os critérios da Norma ABNT NBR 13882, a destinação final do óleo isolante deverá ser feita por incineração e ou descontaminação a valores inferiores a 50mg/kg. Neste trabalho realizado no Instituto de Química de São Carlos - Universidade de São Paulo, desenvolveu-se um procedimento para a descontaminação de óleo contaminado com valor conhecido acima de 50mg/kg...

Produção enzimática de biodiesel etílico em reator de leito fixo e regime de fluxo contínuo uitilizando células íntegras de Mucor Circinelloides imobilizadas em espuma de poliuretano; Enzymatic production of ethyl biodiesel in a packed-bed continuous flow reactor using Mucor circinelloides whole-cell immobilized in polyurethane foam as biocatalyst

Rico, Ana Leticia de Lima
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 28/11/2014 PT
Relevância na Pesquisa
56.81%
O biodiesel, que possui grande potencial para substituição do diesel tradicional na matriz energética, é amplamente estudado pela rota enzimática, cujo biocatalisador pode ser usado de duas formas principais: extra e intracelular. A forma intracelular é considerada mais vantajosa por evitar processos complexos de isolamento, purificação e imobilização, diminuindo o custo efetivo das enzimas. O custo enzimático também pode ser reduzido pela imobilização em suporte adequado. Com base neste contexto, este trabalho teve como objetivo sintetizar e caracterizar espumas de poliuretano utilizando diferentes formulações e verificar a influência das variáveis temperatura, pH, tempo de cultivo e quantidade mássica de suporte no crescimento de biomassa microbiana in situ de Mucor circinelloides URM 4182 nas espumas de poliuretano sintetizadas, visando a aplicação em processo não contínuo e contínuo de produção de biodiesel etílico a partir do óleo de babaçu. Definidas as melhores condições de cultivo, o trabalho teve como foco a otimização dos parâmetros de produção em sistema contínuo e reator de leito fixo: tempo espacial e razão molar óleo:álcool. Na primeira etapa de trabalho, a biomassa imobilizada em pH 5...

Painéis de resíduos madeireiros e de borracha de pneu associados à espuma poliuretana à base de mamona para aplicação como composições termoacústicas ; Panels from wood and tire rubber wastes associated with castor-oil-based polyurethane foam for application as thermo-acoustic compositions

Bertolini, Marília da Silva
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 04/09/2014 PT
Relevância na Pesquisa
66.92%
Questões ligadas ao desempenho térmico e acústico de edificações têm sido cada vez mais abordadas, num cenário em que ganham importância a economia de energia e o controle do ruído. O advento dos materiais compósitos propiciou o emprego de resíduos de processos que, aliados a materiais de origem renovável, contribuem para a obtenção de produtos de reduzido impacto ambiental. Neste contexto, o presente trabalho teve como objetivo a produção e caracterização de painéis de partículas e espuma poliuretana à base de óleo de mamona, para destinação em composições termoacústicas. Os painéis de partículas foram produzidos utilizando-se resíduos de madeira de Pinus sp., tratado com CCB (preservante de cromo, cobre e boro - base óxido), borracha de pneus inservíveis e adesivo poliuretano à base de óleo de mamona. Foram adotadas variações na produção dos painéis, quanto aos fatores: proporção e configuração da borracha, espessura e pressão de prensagem; verificando sua influência no desempenho dos painéis. As propriedades físicas e mecânicas dos painéis foram determinadas conforme a ABNT NBR 14810-3 (2006) e avaliadas segundo os principais requisitos de normas neste âmbito. Análises estatísticas (ANOVA) foram realizadas para verificação da influência dos fatores de produção...

Influência de poros controlados na absorção sonora em espuma de poliuretano rígida; Influence of controlled pores in sound absorption of rigid polyurethane foam

Demoliner, Giordano
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Trabalho de Conclusão de Curso Formato: application/pdf
POR
Relevância na Pesquisa
56.91%
Neste trabalho buscou-se determinar a relação entre o coeficiente de absorção sonora e a variação de poros propositais gerados em uma espuma de poliuretano rígida. Utilizaram-se métodos experimentais, onde se produziram corpos de prova de espuma de poliuretano rígida a partir de processos de expansão. Determinaram-se os coeficientes de absorção sonora dos corpos de prova utilizando-se ensaios de impedância acústica para baixas frequências. As curvas de absorção sonora encontradas nos ensaios mostraram grande similaridade com as curvas de absorção de equipamentos como painéis ressonantes e ressonadores de membrana.; In this work we sought to determine the relationship between the sound absorption coefficient and the variation of pores purposeful generated in rigid polyurethane foam. Experimental methods were used, which produced test bodies of rigid polyurethane foam from expansion processes. The sound absorption coefficients of the specimens were determined using acoustic impedance testing for low frequencies. The sound absorption curves found in trials showed great similarity with the curves for resonant absorption panels and resonators membrane.

Hydrogen sulphide removal from air by biotrickling filter using open-pore polyurethane foam as a carrier

Solcia, R. B.; Ramirez, M.; Fernandez, M.; Cantero, D.; Bevilaqua, D.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 1-8
ENG
Relevância na Pesquisa
56.73%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); A study was conducted on H2S removal in a biotrickling filter packed with open-pore polyurethane foam. Thiobacillus denitrificans was used as inoculum and a mixed culture population was developed during the process. The inhibitory effect of sulphate concentration (1.8-16.8 g L-1), pH (6.9-8.6), trickling liquid velocity (TLV, 9.1-22.8 m h(-1)), H2S inlet concentration (20-157 ppmv) and the empty bed residence time (EBRT, 9-57 s) on the H2S removal efficiency (RE) were thoroughly investigated. An increase in pH from 6.9 to 8.5 led to a corresponding increase in H2S removal. In addition, an inhibitory effect of sulphate concentration was observed from 16.8 g L-1 and the maximum elimination capacity was found to be 22 gS m(-3) h(-1) (RE 98%). The RE was constant (98.8 +/- 0.30%) for EBRT >= 16 s, but a decrease in the EBRT from 16 to 9s led to a corresponding decrease in RE from 98.2 to 89.6% for a TLV of 9.1 m h(-1) and from 97.9 to 94.9% for a TLV of 22.8 m h(-1) (inlet load of 11.0 +/- 0.2 gS m(-3) h(-1)). The sulphur oxidation capacity in the biotrickling filter was not diminished by the presence of other bacteria. (C) 2014 Elsevier B.V. All rights reserved.

Estudo da produção de ácidohialurônico por cultivo de "Streptococus zooepidemicus" em espuma de poliuretano= : Study of the production of hyaluronic acid by "Streptococcus zooepidemicus" cultivation in polyurethane foam; Study of the production of hyaluronic acid by "Streptococcus zooepidemicus" cultivation in polyurethane foam

Felipe Augusto Ferrari
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 16/10/2012 PT
Relevância na Pesquisa
56.91%
Neste trabalho estudou-se a produção de ácido hialurônico por cultivo em estado sólido de Streptococcus zooepidemicus em colunas de leito fixo utilizando espuma de poliuretano (EPU) como suporte inerte. Em um primeiro momento, ensaios preliminares foram desenvolvidos visando um melhor conhecimento do sistema. Constatou-se que este não apresentava robustez suficiente para a otimização e escalonamento do processo. Tendo em vista tais aspectos, foi desenvolvido um novo sistema de leito fixo, o CAS-SSF (central aeration system to solid state cultivation), que direciona o fluxo de ar diretamente no interior do leito, aumentando a eficiência na distribuição de oxigênio. Um delineamento composto central rotacional (DCCR) foi desenvolvido para a concentração inicial de glicose (CIG) e aeração (Aer) objetivando a otimização para essas duas variáveis. Entretanto não foi possível estabelecer um modelo estatístico que se ajustasse satisfatoriamente aos dados experimentais, impossibilitando a análise da superfície de resposta para as variáveis em questão. Contudo, avaliando-se a CIG, pode-se observar que, dentre as condições estudadas, a concentração inicial de 15g.L-1 apresentou maior rendimento de AH por massa de substrato...

Histopathological reaction over prosthesis surface covered with silicone and polyurethane foam implanted in rats

Wagenführ-Júnior,Jorge; Ribas Filho,Jurandir Marcondes; Nascimento,Marcelo Mazza do; Ribas,Fernanda Marcondes; Wanka,Marcus Vinícius; Godoi,Andressa de Lima
Fonte: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia Publicador: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2012 EN
Relevância na Pesquisa
47.35%
PURPOSES: To evaluate whether polyurethane foam leads more intense foreign-body reaction than silicone foam. To compare the vascularization of the capsules surrounding the foam implants. To investigate if the capsule of polyurethane foam implanted has greater amount of collagen than that of silicone foam. METHODS: Sixty-four young male Wistar rats were allocated into two groups: polyurethane foam and silicone foam. Subcutaneous discs were implanted into the dorsum of the animals in both groups. The capsules were assessed 28 days, two months, three months and six months postoperatively. Microscopic analysis with H&E stain was performed to evaluate the acute and chronic inflammatory process, foreign-body reaction and neovascularization. The analysis with picrosirius red was performed using the ImageProPlus software, to measure the number of vessels and collagen types I and III. RESULTS: There were no statistical differences between the two groups regarding the acute and chronic inflammatory processes. All rats from the polyurethane group, in all times, exhibited moderate or intense foreign-body reaction, with statistic significant difference (p=0.046) when compared with the silicone group, in which the reaction was either mild or nonexistent at two months. Vascular proliferation was significantly different between the groups at 28 days (p=0.0002)...

Spectrophotometric Determination of Aluminium in Iron Ores Using Solid-Phase Extraction

Ferreira,Sérgio Luis Costa; Lemos,Valfredo Azevedo; Costa,Antônio Celso Spinola; Jesus,Djane Santiago de; Carvalho,Marcelo Souza de
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/1998 EN
Relevância na Pesquisa
46.96%
In the present paper, a procedure for separation and determination of aluminium in iron matrices is proposed. It is based on the solid-phase extraction of the iron, in the form of thiocyanate complexes, by a polyurethane(PU) foam. The followings parameters were studied: effect of pH and of the thiocyanate concentration on the iron extraction, shaking time required for quantitative extraction, amount of PU foam necessary for complete extraction of iron, aluminium separation from other cations, influence of anions on the iron sorption by PU foam and analytical characteristics of the procedure for aluminium determination using methylthymol blue as chromogenic reagent. The results show that, in the pH range from 1.5 to 4.7, with a thiocyanate concentration of 0.80 mol L-1, by extraction using 1 g of polyurethane foam and a shaking time of 1 min, aluminium (40 mug) can be separated from large amounts of iron (10 mg), 800 mug of copper(II), cobalt(II), zinc(II), mercury(II), tin(IV), manganese(II) and tungsten(V); 100 mug of titanium(IV) and lead(II); and 50 mug of vanadium(V). Calcium(II), barium(II), strontium(II) and magnesium(II) can not be separated by this process, but do not react with MTB under the conditions used for aluminium determination. The anions nitrate...

Studies on indium sorption from iodide medium by polyurethane foam

Ferreira,Elizabeth de M. M.; Morelli,Tadeu; Moreira,Isabel M. N. S.; Carvalho,Marcelo S. de
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2004 EN
Relevância na Pesquisa
56.91%
The sorption behavior of indium iodide onto polyether-based polyurethane (PUF) foam was investigated. The system shows rapid kinetics and maximum sorption from a meaningful range of either acidic or basic media and achieves distribution ratios above 10(4) L kg-1 ([KI] > 0.6 mol kg-1). Sorption equilibrium analysis indicates tetraiodo-indate (MInI4) as the main species sorbed on the foam matrix. A Langmuir isotherm was successfully fitted and values of (1.55±0.02) x 10-1 mol kg-1 and (7.0±1.3) x 10(4) L g-1 were obtained for the saturation capacity Ks and adsorption coefficient b, respectively. The temperature effect was evaluated and the thermodynamic parameters calculated. The values of the equilibrium constant, Kc, decreased with increasing temperature. The negative values of deltaG, deltaH and deltaS indicate a spontaneous and exothermic chemisorption process favored at low temperatures.

Solid-phase extraction of Cu(II) using polyurethane foam and eriochrome black T as ligand for its determination in waters by flame atomic absorption spectrometry

Soriano,Silvio; Cassella,Ricardo J.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2013 EN
Relevância na Pesquisa
66.84%
This work reports the development of a methodology for the selective preconcentration of Cu(II) onto polyurethane foam (PUF) using the Eriochrome Black T (EBT) as ligand. The quantitative extraction of Cu(II) was achieved in a medium containing 60 mg L-1 of EBT and pH 1.5 (adjusted with HCl solution). The minimum time required to obtain total extraction of Cu(II) from solution was 30 min, when 200 mg of PUF were stirred with 100 mL of the samples. The recovery of Cu(II) from the solid-phase only could be performed by digesting the loaded PUF with concentrated HNO3 in a microwave oven (15 min, 600 W). The method was applied for the determination of trace concentrations of Cu(II) in waters by flame atomic absorption spectrometry. A recovery test was performed by spiking of the samples with 20 and 100 µg L-1 of Cu(II) and recovery percentages of 99.4-107% were obtained.

Flexible thermoplastic composite of Polyvinyl Butyral (PVB) and waste of rigid Polyurethane foam

Sônego,Marilia; Costa,Lidiane Cristina; Ambrósio,José Donato
Fonte: Associação Brasileira de Polímeros Publicador: Associação Brasileira de Polímeros
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2015 EN
Relevância na Pesquisa
66.91%
This study reports the preparation and characterization of composites with recycled poly(vinyl butyral) (PVB) and residue of rigid polyurethane foam (PUr), with PUr contents of 20, 35 and 50 wt %, using an extruder equipped with a Maillefer single screw and injection molding. The components of the composites were thermally characterized using differential scanning calorimetry (DSC) and thermogravimetry. The composites were evaluated by melt flow index (MFI), tensile and hardness mechanical tests and scanning electron microscopy (SEM). Tg determined by DSC of PVB sample (53 °C) indicated the presence of plasticizer (Tg of pure PVB is 70 °C). MFI of the composites indicated a viscosity increase with the PUr content and, as the shear rate was held constant during injection molding, higher viscosities promoted higher shear stresses in the composites, thereby causing breaking or tearing of the PUr particles. The SEM micrographs showed low adhesion between PVB and PUr and the presence of voids, both inherent in the rigid foam and in the interphase PVB-PUr. The SEM micrographs also showed that PVB/PUr (50/50) composite exhibited the smallest particle size and a more homogeneous and compact structure with fewer voids in the interface. The stiffness of the composites increases with addition of the PUr particles...

Morphological observation and microbial population dynamics in anaerobic polyurethane foam biofilm degrading gelatin

Tommaso,G.; Varesche,M.B.; Zaiat,M.; Vazoller,R.F.; Foresti,E.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2002 EN
Relevância na Pesquisa
46.99%
This work reports on a preliminary study of anaerobic degradation of gelatin with emphasis on the development of the proteolytic biofilm in polyurethane foam matrices in differential reactors. The evolution of the biofilm was observed during 22 days by optical and scanning electron microscopy (SEM) analyses. Three distinct immobilization patterns could be observed in the polyurethane foam: cell aggregates entrapped in matrix pores, thin biofilms attached to inner polyurethane foam surfaces and individual cells that have adhered to the support. Rods, cocci and vibrios were observed as the predominant morphologies of bacterial cells. Methane was produced mainly by hydrogenothrophic reactions during the operation of the reactors.

Comparison of Polyurethane Foam to Nylon Flocked Swabs for Collection of Secretions from the Anterior Nares in Performance of a Rapid Influenza Virus Antigen Test in a Pediatric Emergency Department ▿

Scansen, Kimberly A.; Bonsu, Bema K.; Stoner, Erin; Mack, Kathy; Salamon, Douglas; Leber, Amy; Marcon, Mario J.
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.99%
Rapid antigen testing of upper respiratory secretions collected with various swab types is often utilized for laboratory diagnoses of influenza virus infection. There are limited data on the effects of swab composition on test performance. This study compared the performance of the Quidel QuickVue Influenza A+B test on secretions from the anterior nares when a polyurethane foam swab was used for collection to that when a nylon flocked swab was used for collection. One hundred subjects who presented to a pediatric emergency department with symptoms suggestive of an influenza virus infection were recruited for the study. Foam and flocked swabs of the anterior nares were obtained from separate nares of each subject before a posterior nasopharyngeal swab was collected and placed into viral transport medium. The QuickVue test was performed directly on each swab type, and the results were compared to the results of reverse transcription-PCR (RT-PCR), direct fluorescent antibody (DFA) test, and viral culture performed on the transport medium. RT-PCR alone and DFA combined with culture were utilized as separate gold standards. There were 56 cases of influenza detected by RT-PCR; the QuickVue test was positive for 40 foam and 30 flocked swabs...

In vitro analysis of polyurethane foam as a topical hemostatic agent

Broekema, Ferdinand I.; van Oeveren, Wim; Zuidema, Johan; Visscher, Susan H.; Bos, Rudolf R. M.
Fonte: Springer US Publicador: Springer US
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.97%
Topical hemostatic agents can be used to treat problematic bleedings in patients who undergo surgery. Widely used are the collagen- and gelatin-based hemostats. This study aimed to develop a fully synthetic, biodegradable hemostatic agent to avoid exposure to animal antigens. In this in vitro study the suitability of different newly developed polyurethane-based foams as a hemostatic agent has been evaluated and compared to commonly used agents. An experimental in vitro test model was used in which human blood flowed through the test material. Different modified polyurethane foams were compared to collagen and gelatin. The best coagulation was achieved with collagen. The results of the polyurethane foam improved significantly by increasing the amount of polyethylene glycol. Therefore, the increase of the PEG concentration seems a promising approach. Additional in vivo studies will have to be implemented to assess the application of polyurethane foam as a topical hemostatic agent.

Cost benefit analysis: closed-cell polyurethane foam use in DoD forward-deployed structures, and as an alternative building material, to reduce operational fuel demand and associated costs

Marsh, Robert J.; Caballero, Steven L.; Gerry, Stephen D.
Fonte: Monterey, California: Naval Postgraduate School Publicador: Monterey, California: Naval Postgraduate School
Tipo: Tese de Doutorado
Relevância na Pesquisa
56.99%
Approved for public release; distribution is unlimited; The purpose of this project is to identify the costs and benefits associated with the application of closed-cell spray foam insulation to forward-deployed, semipermanent/nonpermanent structures, and to provide recommendations regarding future integration, use, and employment. According to the Department of Defense (DOD), forward-deployed generators, used to provide power to base support activities, are the largest single consumer of fuel throughout the battlefield. Eighty percent of the energy provided by generators is assessed to power environmental control units that run incessantly due to the poor insulating properties of the structures, according to a 2010 study conducted by the Department of the Air Force Civil Engineer Support Agency. Recent DOD policy has focused more on energy use and consumption but fails to address, and provide solutions for, major consumers of fuel throughout the battlefield. The incorporation of closed-cell, spray foam insulation into legacy DOD forward-deployed construction practices yields a significant return on investment, short-payback/break-even period, and reduces mission and personnel risk to deployed military forces.; ; Lieutenant Commander...

FLEXURAL BEHAVIOUR OF SANDWICH PANELS COMPOSED OF POLYURETHANE CORE AND GFRP SKINS AND RIBS

SHARAF, TAREK
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
56.86%
This study addresses the flexural performance of sandwich panels composed of a polyurethane foam core and glass fibre-reinforced polymer (GFRP) skins. Panels with and without GFRP ribs connecting the skins have been studied. While the motivation of the study was to develop new insulated cladding panels for buildings, most of the work and findings are also applicable to other potential applications such as flooring, roofing and light-weight decking. The study comprises experimental, numerical, and analytical investigations. The experimental program included three phases. Phase I is a comprehensive material testing program of the polyurethane core and GFRP skins and ribs. In Phase II, six medium size (2500x660x78 mm) panels with different rib configurations were tested in one-way bending. It was shown that flexural strength and stiffness have increased by 50 to 150%, depending on the rib configuration, compared to a panel without ribs. In Phase III, two large-scale (9150x2440x78 mm) panels, representing a cladding system envisioned to be used in the field, were tested under a realistic air pressure and discrete loads, respectively. The deflection under service wind load did not exceed span/360, while the ultimate pressure was about 2.6 times the maximum factored wind pressure in Canada. A numerical study using finite element analysis (FEA) was carried out. The FEA model accounted for the significant material nonlinearities...

Determination of lead by electrothermal atomic absorption spectrometry employing a novel sampling strategy of polyurethane foam impregnated with thiazolylazo-p-cresol (TAC)

Sant'Ana,Otoniel D; Jesuino,Luciene S; Cassella,Ricardo J; Carvalho,Marcelo S; Santelli,Ricardo E
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2004 EN
Relevância na Pesquisa
66.84%
This work presents a method for lead determination by ETAAS, based on solid sampling of polyurethane foam (PUF) impregnated with the reagent 2-(2-thiazolylazo)-p-cresol (TAC) previously utilized to extract the metallic ion from sample solution. The extraction process occurred in a medium buffered in pH 10 with borate system, after 40 min of agitation between the solid and liquid phases. The obtained results showed the easily elimination of the matrix from the graphite tube by a pyrolysis step at 600 ºC, without using of any matrix modifier. The method was validated by analysis of certified materials (biological samples) and by using recovery tests employing saline samples.

Solid phase extraction of Cu(II) as diethyldithiocarbamate (DDTC) complex by polyurethane foam

Sant'Ana,Otoniel D.; Jesuino,Luciene S.; Cassella,Ricardo J.; Carvalho,Marcelo S.; Santelli,Ricardo E.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2003 EN
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This paper presents a study about the sorption of copper-diethyldithiocarbamate complex onto polyurethane foam (PUF). It was observed that the maximum sorption of Cu(II) (80 or 150 µg L-1) was verified at pH 6.8 in presence of 4.5 x 10-5 mol L-1 DDTC. The shaking time needed to achieve the equilibrium was 40 minutes. From these data, a kinetic characterization was performed by applying three models, which revealed that a film diffusion process was a rate-determining mechanism. Results also indicated that a ether-like solvent extraction was the sorption mechanism. The investigation of many metallic ions as concomitants showed that the sorption by foam is relatively selective and it can be enhanced by using a suitable masking agent or incrementing the foam mass.