bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrosedimentological dynamic on Água Fria Watershed
Authors: Silva Alexandre Marco da , Schulz Harry Edmar
Published: November 2007

This study aimed surveying the amount of sediment yielded from the Água Fria watershed (Palmas, Tocantins, Brazil), from February-1998 to January-1999, and investigating the relations between the sediment yield and some environmental and/or antropic factors. The Colby's method was the technique employed for this investigation. The specific sediment yield and sediment delivery ratio were also determined for this period. It was estimated that 138,619 tons of sediment were yielded and the specific sediment yield for the study area was 827 t km-2 y-1, while the sediment delivery ratio was 6.2%. The suspended load was the most dominating fraction in almost all the studied period.
Water balance in karst: case study of the Ribeirão da Onça catchment in Colombo City, Paraná State - Brazil
Authors: Vestena Leandro Redin , Kobiyama Masato
Published: November 2007

With the objective to analyze the hydrological processes and the water balance, a simplified water balance method and the modified Penman formula were applied to the Ribeirão da Onça river catchment in Colombo city, Paraná State. For the analysis, the data obtained during the monitoring period from 1997 to 2000 were utilized. The results showed that the values of the real evapotranspiration estimated by the method of the simplified water balance were negative for the certain periods and for other period sometimes more than those of the potential evapotranspiration estimated by the modified Penman formula. It implied the existence of significant groundwater recharge from other catchments to the study area, and indicates that the simplified water balance method was not suitable for the hydrological study of this karst catchment. The value of the groundwater recharge received by this catchment was estimated as 554 mm/year for the analysis period.
Ensino e pesquisa nos Estados Unidos: algumas características dos principais programas de doutorado em contabilidade
Authors: Murcia Fernando Dal- Ri , Borba José Alonso , Ambrósio Gracieli
Published: November 2007

O presente trabalho busca conhecer algumas características dos principais programas de doutorado em contabilidade dos Estados Unidos. Para a seleção da amostra deste estudo, utilizou-se, como base, o ranking divulgado pela revista U.S. News & World Report - America's Best Graduate Schools in Accounting-2006. Esse ranking lista os 31 principais programas de pós-graduação em contabilidade nos Estados Unidos. Contudo, para o presente trabalho, 3 dessas universidades foram excluídas, restando para análise um total de 28 universidades. A coleta dos dados foi realizada nos sites eletrônicos dos programas selecionados. Buscou-se identificar 4 características desses programas de doutorado: critérios do processo seletivo, exigências para a obtenção do título de Ph.D. in Accounting, disciplinas oferecidas e perfil do corpo docente. Os resultados encontrados evidenciam algumas características dos programas analisados que podem permitir um benchmarking, possibilitando um crescimento da pesquisa acadêmica brasileira. Nesse sentido, o trabalho contribui para a construção e o aperfeiçoamento da contabilidade, à medida que evidencia possibilidades de melhorias nos programas de pós-graduação no Brasil.
Taxocenose de anuros de uma mata semidecídua do interior do Estado de São Paulo e comparações com outras taxocenoses do estado, sudeste do Brasil
Authors: Zina Juliana , Ennser João , Pinheiro Sarah Cristina Piacentini , Haddad Célio Fernando Baptista , Toledo Luís Felipe de
Published: November 2007

O presente estudo foi realizado em um fragmento de floresta semidecídua, Mata São José (MSJ), e em áreas adjacentes ao fragmento localizado no município de Rio Claro, Estado de São Paulo, Brasil. Informações sobre a composição e distribuição espacial e temporal de espécies de anuros foram coletadas entre agosto de 2002 e julho de 2003. Foram registradas 24 espécies, sendo que a maioria foi observada em atividade de vocalização e reprodução nas áreas abertas adjacentes ao fragmento. Apenas três espécies, Hypsiboas lundii, H. prasinus e Proceratophrys boiei foram observadas utilizando ambientes no interior do fragmento para a reprodução e apenas H. prasinus foi registrada também em ambientes adjacentes ao fragmento. A maioria das espécies foi registrada durante a estação chuvosa da região e os ambientes temporários foram os mais utilizados para reprodução. A composição de espécies da MSJ foi comparada com a de outras 10 localidades com as seguintes fisionomias vegetais e status de conservação: floresta tropical preservada, ecótono de floresta ombrófila e floresta estacional semidecídua pouco preservada, Cerrado preservado e áreas antropizadas principalmente pela implantação de agricultura e pastagem. A composição de espécies da MSJ e da área de floresta estacional semidecídua foram mais similares entre si e com áreas perturbadas e área de Cerrado que quando comparadas a composição de espécies da área de floresta tropical preservada. Não houve correlação entre as distâncias e a similaridade na composição da anurofauna das localidades comparadas. Proceratophrys boiei e H. lundii aparentemente são as espécies mais afetadas pelo processo de fragmentação ambiental no Estado de São Paulo, provavelmente devido a sua ecologia e dependência de ambientes mais florestados.
Ecologia reprodutiva de Hydromedusa tecifera (Testudines: Chelidae) no sul do Brasil
Authors: Fagundes Camila Kurzmann , Bager Alex
Published: November 2007

Existem poucos dados na literatura sobre a reprodução de Hydromedusa tectifera (Chelidae), e estes se referem a indivíduos de cativeiro. A ecologia reprodutiva da espécie foi verificada através de monitoramentos não sistemáticos entre 1996 e 2002 na Estação Ecológica do Taim, no extremo sul do Brasil, com a intenção de reunir informações sobre a reprodução da espécie em ambiente natural. Foram encontrados 46 ninhos da espécie, entre intactos e predados. As ninhadas tiveram, em média, 11,6 ovos que apresentaram um tamanho médio de 36,5 x 23,9 mm. A média do peso dos ovos foi de 11,1 g e o seu volume individual resultou em uma média de 10148,31 mm³. Os ninhos alcançaram uma profundidade média de 11,1 e 5,8 cm da superfície ao primeiro ovo. A variação do volume dos ovos de um mesmo ninho foi menor (CV = 4,71%) do que entre diferentes ninhos (CV = 12,32%). A largura dos ovos foi positivamente dependente do seu comprimento. Já em uma mesma ninhada, o número de ovos não dependeu do seu tamanho e do seu volume. Foram observadas desovas nos meses de novembro e dezembro, mas a maioria delas ocorreu na segunda quinzena de novembro. A espécie desovou com maior freqüência no período das 18 às 20 horas, e em áreas com certa inclinação do substrato, entre 20° e 30° de declividade. A maior abundância de ninhos foi observada até 5 m de distância da lagoa. Os resultados encontrados demonstram congruência entre os dados obtidos para H. tectifera e aqueles existentes para cágados-de-pescoço-comprido da Austrália e para as espécies de Chelidae do extremo sul do Brasil.
Espécies de Chalcididae (Hymenoptera, Insecta) do Estado do Espírito Santo, Brasil
Authors: Tavares Marcelo Teixeira , Araujo Bruno Cancian de
Published: November 2007

Uma lista das espécies de Chalcididae (Hymenoptera, Insecta) é apresentada para o Estado do Espírito Santo. Os exemplares são procedentes de 22 localidades e pertencem a 37 espécies e 11 gêneros, sendo que somente duas espécies e cinco gêneros já haviam sido registrados para o Estado. Sete espécies e um gênero são novos registros para o Brasil e duas espécies são registradas pela primeira vez para a região Neotropical. A composição desta fauna é discutida em relação à distribuição geográfica das espécies.
Mutucas (Diptera: Tabanidae) do estado do Paraná, Brasil: chave de identificação pictórica para subfamílias, tribos e gêneros
Authors: Turcatel Mauren , Carvalho Claudio José Barros de , Rafael José Albertino
Published: November 2007

Foi realizado um levantamento das espécies de Tabanidae ocorrentes em todo o Estado do Paraná, com base em dados da literatura, registros da Coleção de Entomologia Pe. Jesus Santiago Moure depositada no Departamento de Zoologia da Universidade Federal do Paraná (DZUP), registros do Museu de Zoologia da Universidade de São Paulo (MZUSP) e em coletas realizadas durante o primeiro ano do Projeto "Levantamento da fauna entomológica no Estado do Paraná" (PROFAUPAR). Foi elaborada uma chave de identificação pictórica para subfamílias, tribos e gêneros ocorrentes no Paraná. Foram confeccionados desenhos esquemáticos dos caracteres diagnósticos dos gêneros, correspondendo à morfologia da cabeça, asa, abdômen e pernas. São registradas 68 espécies, distribuídas em 23 gêneros, seis tribos e três subfamílias; 28 espécies foram registradas pela primeira vez no estado.
A note on the diet and foraging behavior of Artibeus lituratus (Chiroptera, Phyllostomidae) in an urban park in southeastern Brazil
Authors: Oprea Monik , Brito Daniel , Vieira Thiago Bernardi , Mendes Poliana , Lopes Sílvia Ramira , Fonseca Ricardo Milanez , Coutinho Rafael Zerbini , Ditchfield Albert David
Published: November 2007

Bats of the genus Artibeus are among the most important seed dispersers in early successional forests. We report observations on the foraging behavior of Artibeus lituratus in Pedra da Cebola Municipal Park, an urban park in the city of Vitória, Espírito Santo, southeastern Brazil. Observations were made during six consecutive days (April 1st to April 6th, 2006). Three mist-nets were opened each night close to a Maclura tinctoria tree (Moraceae), remaining open from 18:00 to 22:00, totaling four hours per night, and 24 hours of sampling effort. We observed two peaks of feeding activity at the tree, one between 18:20 and 19:30, and a second one at 21:00. This is the first observation of Artibeus lituratus feeding on M. tinctoria fruits, therefore adding a new item to the known diet of the species. M. tinctoria fruits have large seeds that are not swallowed by bats, they consume the fruit pulp and discard the seeds. A diet of fruits with large seeds may indicate an important resource not detected in dietary studies based on fecal samples, but better detected by direct observation or by studying feeding roosts. It is important to use different sampling techniques in dietary studies since they complement each other and, together, provide a better knowledge on the diet of bats.
Prevalence of nonsyndromic oral clefts in a reference hospital in the state of Minas Gerais, Brazil, between 2000-2005
Authors: Martelli-Junior Hercílio , Porto Letícia Vieto , Martelli Daniella Reis Barbosa , Bonan Paulo Rogério Ferreti , Freitas Amanda Beatriz , Coletta Ricardo Della
Published: November 2007

The aim of the present study was to analyze the prevalence of nonsyndromic oral clefts in children receiving treatment at the Center for the Rehabilitation of Craniofacial Anomalies, José do Rosário Vellano University, Alfenas, MG, Brazil. All the data for the epidemiological study was retrieved from the files of 126 pediatric patients with oral clefts without any additional malformation, who came to the center for treatment between 2000 and 2005. A predominance of clefts was observed in Caucasians, and the ratio of male to female was 1.3. Males were 2.57 times more affected by cleft lip and palate (CLP) than females. CLP with a prevalence of 39.68% and isolated cleft lip (CL) with a prevalence of 38.09% were the most common anomalies, followed by isolated cleft palate (CP; 22.23%). Complete and unilateral CLP (26.19%) presented the highest prevalence, followed by incomplete and unilateral CL (23.81%). The present study presents the experience of a reference hospital in the state of Minas Gerais; however, the real prevalence of oral clefts in Brazil is still unknown. Our findings differ from those of a few previous Brazilian reports because they suggest similar prevalences of CLP and CL, and a higher prevalence of CLP in Caucasian males.
New formula to objectively evaluate skeletal maturation using lateral cephalometric radiographs
Authors: Caldas Maria de Paula , Ambrosano Gláucia Maria Bovi , Haiter Neto Francisco
Published: November 2007

The aim of this study was to establish two new formulas for objectively evaluating skeletal maturation of cervical vertebrae in female and male Brazilian subjects using lateral cephalometric radiographs. The sample included 128 girls and 110 boys, aged 7.0 to 15.9 years, from the files of the Oral Radiology Clinic, Piracicaba Dental School, University of Campinas (Unicamp), SP, Brazil. The cervical vertebral bodies of C3 and C4 were traced and measured and regression formulas were developed in order to determine cervical vertebral bone age. Another sample of lateral teleradiographs and hand-wrist radiographs of 55 girls and 54 boys (aged 7.0 to 15.9 years) was used to verify the reliability of the developed regression formulas, as compared with bone age assessed using the Tanner et al.15 (2001) Method (TW3) in hand-wrist radiographs. The analysis of both the boys’ and girls’ data (ANOVA) showed no statistical difference between cervical vertebral bone age, bone age, and chronological age, indicating that these formulas can be used in this population (p = 0.5721 and p = 0.6007 for girls and boys, respectively). Female cervical vertebral bodies of C3 and C4 increased in an accelerated manner from 10 to 13 years. Analysis of the male sample showed that C3 measurements increased in an accelerated manner from 12 to 15 years. The C4 measurements, however, did not increase at all. Using cervical vertebral bone age it is possible to evaluate skeletal maturation objectively in cephalometric radiographs.
Site-specific traffic load modelling for bridge assessment
Authors: O'Connor A. , Eichinger E. M.
Published: November 2007

Assessment of highway bridge structures requires accurate prediction of the load effects that a structure may be expected to resist during its required remaining life. Generally, these load effects are determined from codified models more appropriate to design than assessment. This approach is very conservative for existing structures as it fails to fully recognise the reduced level of uncertainty associated with evaluation of (a) the loads to which an existing structure is subjected and (b) the resistance that an existing structure provides. This paper proposes a more rational approach to load effect prediction for existing structures. In the approach the actual traffic loading to which a structure is subjected is measured on site and is employed in simulation to determine site-specific characteristic load effects. The methodology proposed is dependent upon the availability of unbiased site-specific traffic statistics. This paper presents the results of an experiment performed in Vienna and describes the use of weigh-in-motion (WIM) statistics in the prediction of site-specific characteristic load effects—that is, values with specified probability of exceedance during the required lifetime of the structure, against which the structure may be assessed. The advantage of the approach is demonstrated through reductions in the load effect values. The implication for bridge assessment is reduced rehabilitation costs and the avoidance of unnecessary replacement of serviceable highway structures.
Pendel bearing replacement at A9 Kessock Bridge, Scotland
Authors: Redpath J.
Published: November 2007

The A9 is the primary north–south trunk route in the Scottish Highlands and bypasses the city of Inverness by means of Kessock Bridge, a major cable-stayed structure spanning the Beauly Firth and opened to traffic in 1982. The bridge is a 1052 m long viaduct with a main cable-stayed span of 240 m, 80 m back spans and a number of 64 m and 72 m approach spans. At the ends of the 80 m back spans, four pendel-type bearings were installed to accommodate uplift reaction due to loading on the main span. These pendel bearings became excessively worn over time and required replacement. This paper describes the design and construction issues associated with replacement of these critical structural elements, an operation made more challenging by the very constrained geometry and the need to maintain overall stability of the bridge under operational traffic conditions.
Transparent and conducting SWNT thin films for flexible electronics
Authors: Chhowalla Manish
Published: November 2007

Abstract— Thin films from low‐density networks of single‐walled carbon nanotubes (SWNTs) are intriguing new two‐dimensional electronic materials because they have excellent tunable electrical, optical, and mechanical properties. Such properties coupled with room‐temperature deposition from solution ensure that the material will have profound impact on emerging technologies such as cheap, flexible plastic electronics and smart fabrics and windows. These optoelectronic properties of SWNT thin films make them a potentially good replacement for indium tin oxide (ITO), used widely in photovoltaics, organic, and inorganic light‐emitting diodes, displays, touch screens, and smart windows.
Fabrication of low‐temperature‐polysilicon thin‐film transistors on flexible substrates using excimer‐laser crystallization
Authors: Kim Yong‐Hoon , Kim Won‐Keun , Han Jeong‐In , Moon Dae‐Gyu
Published: November 2007

Abstract—Low‐temperature‐polysilicon thin‐film transistors (LTPS TFTs) were fabricated on polymer substrates using sputtered amorphous‐Si (a‐Si) films and excimer‐laser crystallization. The in‐film argon concentration of a‐Si films was minimized as low as 1.6% by using an argon/helium gas mixture as the sputtering gas. By employing XeCl excimer‐laser crystallization, poly‐Si films were successfully fabricated on polymer substrates with an average grain size of 400 nm. With a four‐mask process, a poly‐Si TFT was fabricated with a fully self‐aligned top‐gate structure, and the pMOS TFT device showed a field‐effect mobility of 63.6 cm2/V‐sec, ON/OFF ratio of 105, and threshold voltage of −1.5 V.
Understanding Interest System Diversity: Health Interest Communities in the American States
Authors: Lowery David , Gray Virginia
Published: November 2007

Recent work suggests that the most fruitful approach to accounting for variations in interest system diversity of any type lies in understanding variations in interest system density (Lowery, Gray and Fellowes 2005). We build on this insight by examining the sources of variation in the substantive diversity of health interests in the American states, focusing on how the densities of several sub-guilds of health interest organizations vary in their responses to changes in the sizes of the constituencies that give rise to them and variations in the policy and political energy supporting their mobilization. We discuss the concept of interest system diversity in the first section of the paper, highlighting its multiple meanings and the limits of prior research. This is followed by a close empirical examination of 14 sub-guilds of state health interest organizations. We conclude by discussing the inherent difficulties of understanding interest system diversity.
An Obsolescing Bargain in Chad: Shifts in Leverage between the Government and the World Bank
Authors: Gould John A. , Winters Matthew S.
Published: November 2007

This paper applies the insights of obsolescing bargaining theory to a situation in which a host country interacted with both multinational corporations and an international organization, the World Bank. Drawing on resource curse literature and the Rubinstein bargaining model, we demonstrate the continued usefulness of obsolescing bargaining theory by explaining why the World Bank had to renegotiate its initial bargain with Chad in the Chad-Cameroon Oil Pipeline Project. The paper explores how specific bargaining parameters changed over time in this case and suggests how resource curse dynamics and their impact on domestic politics might be particularly relevant for bargaining between host countries and international actors. The case study serves as a warning to international financial institutions and corporations alike with regard to the ways in which obsolescing bargains can arise in the contemporary global political-economy.
Rapid Solar-thermal Decarbonization of Methane in a Fluid-wall Aerosol Flow Reactor -- Fundamentals and Application
Authors: Wyss Jeffrey , Martinek Janna , Kerins Michael , Dahl Jaimee K , Weimer Alan , Lewandowski Allan , Bingham Carl
Published: November 2007

A graphite fluid-wall aerosol flow reactor heated with concentrated sunlight has been developed over the past five years for the solar-thermal decarbonization of methane. The fluid-wall is provided by an inert or compatible gas that prevents contact of reactants and products of reaction with a graphite reaction tube. The reactor provides for a low thermal mass that is compatible with intermittent sunlight and the graphite construction allows rapid heating/cooling rates and ultra-high temperatures. The decarbonization of methane has been demonstrated at over 90% for residence times on the order of 10 milliseconds at a reactor wall temperature near 2000 K. The carbon black resulting from the dissociation of methane is nanosized, amorphous, and ash-free and can be used for industrial rubber production. The hydrogen can be supplied to a pipeline and used for chemical processing or to supply fuel cell vehicles.
Fluidized Bed Steam Gasification of Solid Biomass - Performance Characteristics of an 8 MWth Combined Heat and Power Plant
Authors: Pröll Tobias , Rauch Reinhard , Aichernig Christian , Hofbauer Hermann
Published: November 2007

The work focuses on a dual fluidized bed gasification technology that is successfully operated for combined heat and power production at a scale of 8 MWth in Guessing/Austria since 2002. The reactor concept consists of a circulating fluidized bed system with a steam-fluidized bubbling bed integrated into the solids return loop. Accompanying the operation of the commercial scale plant, parameter models have been developed and validated by comparison to measured data. As the models naturally fulfill mass and energy balances, the simulation also allows the validation of measurement data. The behaviour of the plant is studied by carrying out variations of selected parameters. Evaluation of different plant operation cases yields correlations between process variables. The solids circulation rate is shown versus riser exit velocity. Fuel water content and gasification temperature significantly influence global plant performance. Simulation predicts the efficiency of the existing power plant in optimized operation. Finally, part load behaviour is investigated and performance maps of the CHP plant are presented. High fuel water content at high gas engine load results in high gas velocities in the riser (erosion limit) and higher heat ratio in the produced energy. It is concluded that CHP-concepts based on fluidized bed steam gasification can reach high electric efficiencies and high overall fuel utilization rates even at small plant capacities of about 10 MWth.
Supercritical Fluid Extraction of Binary Systems of Monoolein, Diolein and Triolein, Using Carbon Dioxide Solvent
Authors: Kassim K. M. , Davarnejad R.
Published: November 2007

Supercritical fluid extraction solubility data for monoolein, diolein and triolein in carbon dioxide were measured using a phase equilibrium re-circulation high-pressure type apparatus at 60° C and at various pressures. In order to examine the supercritical fluid extraction operation effects at high-pressures, detailed experimental determination were made on the compositions of the equilibrium vapor and liquid phases in the system (carbon dioxide/monoolein, carbon dioxide/diolein and carbon dioxide/triolein) at various conditions. It was found that weight fractions of up to 1% of monoolein could be obtained in the vapor phase. This might be sufficient to make supercritical fluid extraction using carbon dioxide solvent a possibility for this component. This renders a separation by simple distillation impossible. These systems were modeled based on the Redlich-Kowng equation of state. The experimental data was found to agree well with the data obtained by the model.
Catalytic Wet Air Oxidation of Oxalic Acid at Atmospheric Pressure
Authors: Gunduz Gonul , Dukkanci Meral
Published: November 2007

Catalytic wet air oxidation of oxalic acid in aqueous solution was investigated in a stirred reactor over a Pt (0.7% in wt)/Al2O3 catalyst at atmospheric pressure, in a concentration range of oxalic acid of 500-3000 ppm, and at a temperature range of 313-353 K. The conversions obtained after 5 h were 28.96 %, 45.98 % and 30.74 % for initial concentrations of 500, 1500, 3000 ppm, respectively. A rate equation of oxalic acid oxidation, in mol.h-1.g-1Pt was determined from measurements of initial rates, at different initial concentrations of oxalic acid, temperatures and catalyst mass loads. The activation energy for oxalic acid conversion was found to be 24.6 kJ mol-1.The heterogeneous catalyzed free-radical oxidation of oxalic acid was discussed.
Flow Pulsation and Modified Duct Surface for Process Heat Transfer Intensification
Authors: Olayiwola Bolaji O , Walzel Peter
Published: November 2007

An experimental investigation of the combined influence of flow pulsation and modified duct surface on cross-flow transport and convective heat transfer intensification in laminar flow was carried out. The experiments were performed with a fluid with a kinematic viscosity of 1.8x10-6 m2/s and Prandtl number of Pr = 15. The active length L of the channel is 900 mm and lateral extension is W = 90 mm. Pulsation amplitude (A range of 0.28 mm  0.53 mm) was used together with pulsation frequency (range of 16 Hz ? f ? 54 Hz). A steady flow Reynolds number range of 100 < Re < 600 was studied. All the geometric parameters of the device such as the relative fin spacing and relative fin thickness were constant. The results of the flow visualization showed recirculation eddies formation when flow pulsation and fins are combined. This enhances the mixing of the fluid within the channel. The intensification of the heat transfer coefficient due to pulsation and use of fins becomes more significant with increasing pulsation amplitude. The combined influence of flow pulsation and modified surface geometry on the heat transfer coefficient was found to be significant at moderately low but non-zero net flow rates or Peclet number Pe. Maximum heat transfer intensification of 2.4 was obtained. In general, no significant heat transfer was obtained at very low and very high flow rates.
Semi-industrial-scale Process for Dilute Swine Wastewater Treatment Using a Submerged Membrane Bioreactor (MBR) with Direct Reuse of Treated Water
Authors: Prado Nolwenn , Ochoa Juan , Audic Jean-Luc , Amrane Abdeltif , Meinhold Jens
Published: November 2007

The performances of a semi-industrial-scale membrane bioreactor to treat dilute swine wastewater were investigated on a 3 month running period. The treated water was directly reused in the piggery for flushing purposes. The pilot was proved to have good performances in terms of ammonium removal (99%), and COD removal (86%), despite an accumulation of heavy metals in the biological tanks (up to 17 mg/L for zinc and up to 115 mg/L for copper). 79% of the total phosphorus was eliminated through the process, 61% via centrifugation and 18% by biological uptake. The pilot showed a good adaptability to the variations of the loading rates of dilute swine wastewater's major components (COD, TN, TP, heavy metals).
Purification Process of Stevioside Using Zeolites and Membranes
Authors: Silva Flávia Vieira , Bergamasco Rosângela , Andrade Cid Marcos G , Pinheiro Nanci , Machado Nádia Regina Camargo Fernandes , Reis Miria Hespanhol M. , de Araújo Álvaro Alberto , Rezende Suzana Lemanski
Published: November 2007

Stevia rebaudiana is a plant native of South America, and its active constituents are considered, by Food Science researchers, the "sweeteners of the future." Therefore, research on this plant has been increased. Stevia is a source of natural diet sweetening, without calories and safe for health. Its crude extract, however, is foul-smelling, bitter tasting, and dark brown; subsequent purification is essential to obtain a product of commercial quality. In this work, adsorption in modified zeolites associated with the filtration with membranes was applied in order to purify stevia crude extract. For the adsorption process, 40 g of CaX modified zeolites were used. In the ultrafiltration process, membranes with porosities of 0.05, 0.1 and 0.2 ?m were used. The transmembrane pressure was fixed at 2, 4 and 6 bar for each membrane. The best conditions of flux were obtained with the 0.2 ?m membrane and 6 bar, resulting in high clarification and recuperation of stevioside (91.75%). This work shows that the adsorption in modified zeolites associated with the membrane filtration is promising for stevia extract purification.
Kinetic Study of Various Chars Steam Gasification
Authors: Paviet Frédéric , Bals Olivier , Antonini Gérard
Published: November 2007

Gasification is an attractive technology for waste thermal treatment. The successful design and modelling of a gasifier requires reliable kinetic data. The purpose of this work is to study the steam gasification kinetics of chars produced by municipal wastes pyrolysis. The municipal solid wastes (MSW) are modelled as a mixture of four organic constituents: paper, wood, plastics, and vegetables. The various char samples are obtained by pyrolysis of each waste constituent, in a fixed bed reactor at 1000°C, in order to minimize their volatile content and thus, to eliminate any subsequent devolatilization of the carbonaceous residues. These chars are used as raw materials in steam gasification experiments. The gasification studies are performed on each char separately, in a tubular kiln at various temperatures (900°C, 950°C and 1000°C) and various vapour pressures (0.2 bar, 0.5 bar and 0.7 bar). The gases produced are analysed by gas chromatography in order to determine the gasification kinetics. The kinetics parameters, with respect to H2O, together with the influence of the char's physical properties are experimentally determined. A kinetic expression for the gasification reaction, based on the random pore model is deduced. It is shown that the char resulting from the pyrolysis of MSW constituents, essentially paper, wood and vegetables have the same gasification kinetics. On the contrary, the plastic char steam gasification kinetic appears to be significantly slower.
Relation between Respirometric Data and Amylolytic Enzyme Production by SSF in Column-Type Bioreactor
Authors: Spier Michele Rigon , Greiner Ursula Konietzny , Greiner Ralf , Rodriguez-León Jose Angel , Carvalho Julio Cesar , Woiciechowski Adenise Lorenci , Soccol Carlos Ricardo
Published: November 2007

The use of agro industrial by-products like cassava starch and sugar cane bagasse show great potential as substrates and support amylases production by solid-substrate fermentation (SSF). The production of amylolytic enzymes by Aspergillus niger LPB 28 increased with forced air using a column fermentation system and optimized conditions in a column bioreactor when it was followed by kinetics of respiratory metabolism. The O2 consumption and CO2 production by A. niger were measured in the top of the columns through the use of a GC system linked to a program for chromatograph control and integration with 2m length, with helium as the carrier gas and a thermal conductivity detector. The kinetic parameters were determined using the program FERSOL.
Controlled Synthesis of Alumina Nanoparticles in a Reactor with Self-Impinging Plasma Jets
Authors: Kolesnikov Andrei V , Alexeev Nikolay , Samokhin Andrey
Published: November 2007

With the recent interest in the application of nanoscale metal and metal oxide particles, there is now interest in manufacturing these materials in larger quantities. A number of techniques have evolved for the synthesis of nanopowders. For metal and metal oxide nanoparticles where coalescence is the dominating growth mechanism, concentration and the timetemperature history of the nanoparticles resulting from the reactor design determines the final particle average diameter. In this paper, we present the results of controlled synthesis of alumina nanopowder in a three-jet plasmachemical reactor, where temperature and velocity distributions are controlled by the angle of impingement of the plasma jets. The flow and temperature fields for various impingement angles were measured by an enthalpy probe. The products were characterized by means of electron microscopy, XRD analysis, and BET analysis. The dependences of particle size on the operation parameters (injection velocity of raw material, plasma jet enthalpy, solid/gas mass flow rates ratio, and impingement angle of plasma jets) are discussed. In comparison with the single jet reactor, the novel reactor can increase the production rate several times to manufacture the product with the same required surface area.
Self-Cleaning Test of Doped Anatase-Coated Glass Plates
Authors: Medina-Valtierra Jorge , Campos-Reyna Silvia Janneth , Frausto-Reyes Claudio , Calixto Sergio , Ramírez-Ortíz Jorge
Published: November 2007

Doped anatase thin films on glass were deposited by ultra-spinning from titanium isopropoxide-based sol-gels. To test the self-cleaning properties of anatase-coated glass, crystalline fluoranthene, a polycyclic aromatic compound, was sprayed over the glass and then irradiated using a 365 nm UV source. This anthropogenic contaminant was removed until 98 wt.% at 140 h of irradiation time with the 2 wt.% zinc ferrite-doped anatase film. The fluoranthene proportion degraded on anatase-free glass was much lower than with anatase coating giving only 12% for an irradiation time of 140 h. In this form, the coated-glass transparency was recovered almost totally at this irradiation time for the doped anatase film mentioned, which did not occur with anatase-free glass, even after more than 400 h of UV irradiation. A correlation was found between the total weight losses of the solid compound and the intensity of the Raman vibration at 671 cm-1 during photocatalytic degradation. After 140 h of irradiation, while the presence of fluoranthene is not detected by Raman spectroscopy, glass plate presented ultra-thin zones of degradation products. Thus, the removal of these intermediate products deposited on glass was directly measured by means of weight difference. The self-cleaning properties of doped anatase coating on window glass could have a positive influence on outdoor and indoor air quality. In this work, degradation mechanisms and intermediate products were not discussed or identified.
Reuse of Fried Oil to Obtain Biodiesel: Zeolites Y as a Catalyst
Authors: Brito A. , Borges M. E. , Arvelo R. , Garcia F. , Diaz M. C. , Otero N.
Published: November 2007

The transesterification reaction is the most utilized process to obtain biodiesel. Fried oil transesterification reactions with methanol have been studied using several zeolites Y and interchanged with CsCl and KOH. The reaction has been carried out both in a slurry reactor and a fixed bed catalytic reactor. The catalytic effects of zeolites have been tested within a temperature range of 60-476°C, 2.5-5% catalyst/waste oil weight ratio, and 6:1 - 100:1 methanol/oil molar ratio. Cosolvents (THF, n-hexane) in the reaction feedstock effect have also been studied as well as catalyst regeneration effects. Viscosity of both the oil and the transesterification reaction products was determined as an initial guide to investigate the degree of conversion to biodiesel as well as FAME content by GC. When interchanged zeolites are used conversions are improved, getting the best yields (98% FAME) for the Y756 zeolite interchanged with KOH. Viscosities of the reaction product obtained reached values next to diesel standard ones.
Green Diesel: A Second Generation Biofuel
Authors: Kalnes Tom , Marker Terry , Shonnard David R.
Published: November 2007

Environmentally-conscious design of processes and products is increasingly viewed as an important strategy in the sustainable development of new refining and chemical processes. This paper discusses a new process technology developed by UOP and Eni S.p.A; the UOP/Eni EcofiningTM process to produce green diesel from vegetable oil. This novel process utilizes catalytic saturation, hydrodeoxygenation, decarboxylation and hydroisomerization reactions to produce an isoparaffin-rich diesel fuel from renewable feedstock containing triglycerides and fatty acids. The resultant biofuel product has a high cetane value, a lower gravity, good cold flow properties and excellent storage stability. Green diesel is completely compatible for blending with the standard mix of petroleum-derived diesel fuels, thus providing significant value to the refiner. The process for producing green diesel operates at mild operating conditions and integrates well within existing petroleum refineries. In contrast to fatty acid methyl esters, where fuel properties depend on feed origin and process configuration, green diesel product is independent of feed origin and the fully deoxygenated biofuel is readily blended with conventional diesel fuel. A life cycle assessment (LCA) of this promising new biofuel production technology has been undertaken to quantify the intrinsic benefits of green diesel production over the current practice of converting various forms of lipids to fatty acid methyl esters. This paper will describe the technology, discuss the results of the LCA study and summarize the advantages this new technology can offer over other processing routes.
Characterization of the Liquid Obtained in Tyre Pyrolysis in a Conical Spouted Bed Reactor
Authors: Arabiourrutia Miriam , Lopez Gartzen , Elordi Gorka , Olazar Martin , Aguado Roberto , Bilbao Javier
Published: November 2007

Used tyres pose a serious environmental problem and pyrolysis is considered one of the more feasible solutions that may be economically profitable on a large scale. In this study the pyrolysis of tyres has been carried out in a conical spouted bed reactor at 500 °C and the liquid product has been characterized taking into account composition, heat value and simulated distillation. The tyre mass feed in each run was 2 g and the bed was made up of 15 g of sand. Pyrolysis of scrap tyre at the 500 °C gives way to a yield of 3.1% of gases, 37.6% of liquid fraction (C5-C10 range hydrocarbons), 25.6% of tar (C11+) and 33.7% of char. The liquid fraction is of suitable quality for its use as fuel but the char requires activation for its upgrading.
Influence of the Anatase/Rutile Ratio on the TiO2 Photocatalytic Activity for the Photodegradation of Light Hydrocarbons
Authors: Collins-Martínez Virginia , López Ortiz Alejandro , Aguilar Elguézabal Alfredo
Published: November 2007

A set of TiO2 samples with different anatase/rutile ratios was prepared by calcinations at different temperatures from commercial photocatalyst Degussa P25. The effects of the two crystalline phases of titanium (IV) oxide on the photocatalytic activity in gaseous phase through oxidation of light hydrocarbons were studied. Crystalline phase transformation from anatase to rutile occurred at 700°C for P25. Results indicate that samples with higher anatase/rutile ratios presented higher intrinsic activities for the photodegradation of a propane/isobutane/butane (40/35/25 %V) mixture. However, the activity did not totally disappear after complete crystalline transformation from anatase to rutile, indicating that the pure rutile phase also presents photoactivity. During the photocatalytic reaction of TiO2 samples, a linear dependence was found between the inverse of the intrinsic reaction rate constant (k intrinsic) and the water adsorption capacity in the surface (WAPS) of the synthesized TiO2 catalyst. The thermal treatment used to induce the formation of rutile by calcination would presumably reduce water adsorption capacity and surface area, leading to a decrease in photocatalytic activity.
A Bayesian Approach to Estimation and Testing in Time-course Microarray Experiments
Authors: Angelini Claudia , De Canditiis Daniela , Mutarelli Margherita , Pensky Marianna
Published: November 2007

The objective of the present paper is to develop a truly functional Bayesian method specifically designed for time series microarray data. The method allows one to identify differentially expressed genes in a time-course microarray experiment, to rank them and to estimate their expression profiles. Each gene expression profile is modeled as an expansion over some orthonormal basis, where the coefficients and the number of basis functions are estimated from the data. The proposed procedure deals successfully with various technical difficulties that arise in typical microarray experiments such as a small number of observations, non-uniform sampling intervals and missing or replicated data. The procedure allows one to account for various types of errors and offers a good compromise between nonparametric techniques and techniques based on normality assumptions. In addition, all evaluations are performed using analytic expressions, so the entire procedure requires very small computational effort. The procedure is studied using both simulated and real data, and is compared with competitive recent approaches. Finally, the procedure is applied to a case study of a human breast cancer cell line stimulated with estrogen. We succeeded in finding new significant genes that were not marked in an earlier work on the same dataset.
Improving Preceptor Self-Efficacy Using an Online Educational Program
Authors: Parsons Rachelle
Published: November 2007

The purpose of this study was to evaluate the effectiveness of a public/community health online preceptor education program on knowledge of the preceptor role and self-efficacy to perform in the preceptor role. Forty-eight public/community health nurses from five states completed an online education program, a 32-item quiz and a preceptor self-efficacy instrument. Preceptor self-efficacy and knowledge scores improved significantly after completing the online education program compared to pretest scores. Previous experience as a preceptor, age, and place of employment, were not correlated with preceptor self-efficacy scores. Previous preceptor education and highest level of education completed were positively correlated with preceptor self-efficacy scores. Previous preceptor education was reported by 39.6% of nurses. However, there was no standard curriculum for these education programs. The results of this study support the use of online education as a method for enhancing preceptor knowledge and confidence in the preceptor role.
A Comparison of Clinical Simulation and Case Study Presentation on Nurse Practitioner Students' Knowledge and Confidence in Managing a Cardiac Event
Authors: Scherer Yvonne K , Bruce Susan A , Runkawatt Viliporn
Published: November 2007

The study was designed to compare the efficacy of controlled simulation mannequin (SM) assisted learning and case study presentation on knowledge and confidence of nurse practitioner (NP) students in managing a cardiac event. Twenty-three volunteer students were randomly assigned to the experimental (simulation) or control (case study presentation) group. All participants were instructed on atrial arrhythmias, were pre- and post-tested on knowledge and confidence, and completed an evaluation of the experience. There were no statistically significant differences in knowledge test scores, although the control group scored significantly higher on post- test confidence (p=.040). Both groups rated their experience as valuable. The simulation and case study presentation had similar outcomes. Additional research is needed to determine the effectiveness of this teaching modality.
Time to Change U.S. Climate Policy
Authors: Hahn Robert , Passell Peter
Published: November 2007

Carbon taxes are not likely to be politically feasible in the U.S. for addressing climate change in the short term, according to Robert Hahn and Peter Passell. The time is now ripe for the U.S. to consider adopting a cap and trade approach to reducing greenhouse gas emissions.
Ginger Modulates Lymphocyte Activity in Vitro and in Vivo and Modestly Prolongs Cardiac Allograft Survival
Authors: Wilasrusmee Chumpon , Kittur Smita , Tripathi Sudipta , Shah Gaurang , Bruch David , Kittur Dilip S
Published: November 2007

Objectives: Ginger, an herb with diverse pharmacotherapeutic properties, is used as an anti-inflammatory agent in immunological disorders like rheumatoid arthritis. The objective of the present investigation was to study the effect of ginger on alloreactivity and on prolongation of cardiac allograft in mice.Design: We tested the effect of ginger extract on lymphocytes in vitro and in vivo and the response of ginger treated lymphocytes to allostimulation and cytosine release. We also studied the effect of ginger extract on cardiac allograft survival in a non vascularized transplantation model in mice.Results: We observed an immunosuppressive effect of ginger in vitro and in vivo. Ginger extract decreased lymphocyte proliferation in response to allostimulation. Ginger extract also decreased the production of the immunostimulatory cytokines IL-2, IL-4 and IFN-? and increased the production of the immunomudulatory cytokines IL-10 and TGF?1. Ginger extract by itself produced a modest increase in the survival of cardiac allografts in mice survival.Conclusion: Our study demonstrates that ginger extract has immunosuppressive effects both in vitro on lymphocyte proliferation and cytokine production and in vivo on allograft survival.
Steady-State and Dynamic Behavior of a Single-Phase Self-Excited Induction Generator Using a Three-Phase Machine
Authors: Mahato S. N. , Sharma M. P. , Singh S. P.
Published: November 2007

This paper presents the steady-state and transient behavior of a single-phase self-excited induction generator (SEIG) using a three-phase machine with one shunt and one series excitation capacitors for resistive and inductive loads. The generation scheme consists of one three-phase delta connected induction machine and two capacitors - one connected in parallel with one winding and the other in series with a single-phase load. The dynamic model of the system has been developed as a hybrid model considering the stator phase currents in abc reference frame and the rotor currents in stationary d-q axes reference frame as state variables. The simulated and experimental results are presented for different dynamic conditions such as initiation of self-excitation, load perturbation and short-circuit. The simulated results of the steady-state analysis have been compared with the transient and experimental results and a close agreement between them indicates the accuracy and effectiveness of the approach.
Probabilistic Index for Increasing Hourly Transmission Line Ratings
Authors: Bracale Antonio , Andreotti Amedeo , Carpinelli Guido , De Martinis Umberto
Published: November 2007

The steady state thermal rating of overhead transmission lines is limited by the conductor`s maximum design temperature, which is related to the maximum sag and the loss of tensile strength of the conductors. Traditionally, this overhead transmission lines rating is computed using a deterministic approach, with reference to severe weather conditions. Thus, the application of this method leads to conservative results resulting in under-utilization of conductors. In this paper, a new method based on an hourly probabilistic index is proposed to predict the line thermal rating for each hour of the day; this index is evaluated using the conductor current limit probability density function (pdf). The method uses Bayesian time series models for the weather parameters (ambient temperature, wind speed and wind direction) and calculates the conductor current limit pdf using a Monte Carlo simulation. The probabilistic index is applied by considering measured weather data of both hot and cold seasons; the corresponding lines ratings are reported and analyzed.