bluuebunny/crossref_metadata_2025 huggingface dataset:
Módulo de elasticidade de grãos de milho submetidos a impactos mecânicos
Authors: Ruffato Solenir , Couto Sandra M. , Queiroz Daniel M. de
Published: November 2006

Neste trabalho investigou-se a viabilidade de se obter o módulo de compressão de grãos de milho, utilizando-se dados experimentais de força versus tempo, provenientes de testes de impacto, juntamente com uma análise estrutural elástica do processo. Os módulos de elasticidade foram determinados para grãos, a diferentes teores de umidade, submetidos a impactos de diferentes velocidades, e obtidos por um processo de otimização por meio da técnica de elementos finitos. Dois tipos de módulo foram avaliados: (a) um módulo efetivo para todo o grão e (b) um módulo para cada uma das três regiões, com diferentes características, segundo as quais o grão foi dividido. O teor de umidade e a velocidade de impacto influenciaram nos valores dos módulos. Módulos para grãos a 13,4% base úmida (b.u.) foram maiores do que para aqueles a 20,0% b.u. A análise realizada (elástica) mostrou-se ser mais adequada na obtenção de módulos de elasticidade de grãos a 13,4% b.u.; neste teor, os grãos apresentam características elásticas mais pronunciadas que quando a 20,0% b.u. e, nos grãos com altos teores de umidade, as características viscoelásticas tornam-se predominantes.
Desempenho da cultura do arroz irrigado com esgotos sanitários previamente tratados
Authors: Sousa José T. de , Leite Valderi D. , Luna João G. de
Published: November 2006

Com o presente trabalho, objetiva-se avaliar o desempenho da cultura do arroz, irrigada com efluentes de esgoto sanitário provenientes de tanque séptico e de lagoa de estabilização, tomando-se como referencial comparativo a mesma cultura irrigada com água de abastecimento em solos fertilizados com adubos minerais e sem adubo mineral. No experimento foi utilizada a cultivar Diamante, originada da EMBRAPA Meio Norte, e o sistema experimental era constituído por 4 tabuleiros com 10 m² de área unitária, irrigados por inundação intermitente, procurando-se manter sempre uma média de 5 cm de lâmina líquida a cada dois dias, durante o período de 4 meses. A análise dos dados demonstra que a produtividade da cultivar Diamante, irrigada com efluente de tanque séptico, foi superior à produtividade da mesma cultivar irrigada com água de abastecimento em solo com adubação mineral. Salienta-se, ainda, que os grãos da cultivar irrigada com efluente do tanque séptico não apresentaram, em nenhum exame, indicadores de contaminação fecal.
Seed germination of Bowdichia virgilioides Kunth, under water stress
Authors: Silva Lígia M. de M. , Aguiar Ivor B. de , Rodrigues Teresinha de J.D.
Published: November 2006

Bowdichia virgilioides (Leguminosae-Papilionoideae) is a native tree species in Brazil characteristic of the savannah vegetation. Seeds of this species were submitted to different osmotic potentials induced by polyethyleneglycol (PEG-6000) in order to verify their resistance to drought conditions. Seeds were previously scarified with sulphuric acid and incubated at 25 ºC with an eight hours photoperiod, at osmotic potentials of 0.0, -0.1, -0.3, -0.5, -0.7, -0.9 and -1.1 MPa. It was found that water stress resistance limit ranged from -0.7 to -0.9 MPa. Significant reduction in germination velocity from -0.3 MPa, and final percentage of germination from -0.5 MPa in relation to control, were observed. Germination under drastic conditions of water stress was inhibited, but was restored with an increase of water availability.
Influência da declividade do solo e da energia cinética de chuvas simuladas no processo de erosão entre sulcos
Authors: Amorim Ricardo S.S. , Silva Demetrius D. da , Pruski Fernando F. , Matos Antonio T. de
Published: November 2006

Utilizou-se um simulador de chuvas e um canal de solo para se avaliar o efeito da declividade da superfície do solo e da energia cinética decorrente das chuvas simuladas nas perdas de solo em áreas entre sulcos. O experimento consistiu de um esquema fatorial, com cinco valores de energia cinética (495, 832, 1.151, 1.541 e 1.959 J m-2) correspondentes às intensidades de precipitação de 30, 46, 69, 88 e 107 mm h-1, respectivamente, e cinco declividades da superfície do solo (2, 6, 10, 14 e 18%). Nos testes foi utilizado o horizonte A de um Latossolo Vermelho-Amarelo. A perda de solo foi determinada pelo método direto e uma equação de regressão foi obtida, tendo-se como variável dependente a perda de solo e, como variáveis independentes, a declividade da superfície do solo e a energia cinética da precipitação. Os resultados mostraram que a perda acumulada de solo ao longo do tempo apresentou comportamento com tendência linear proporcionando, desta forma, taxas de perda de solo constantes ao longo dos testes e que a perda total de solo aumentou à medida que os valores de declividade da superfície do solo e energia cinética foram aumentados, sendo que o efeito da declividade na perda de solo foi menos expressivo que o da energia cinética.
Condutividade hidráulica saturada em um solo aluvial do perímetro irrigado de São Gonçalo, PB
Authors: Barreto Aurelir N. , Oliveira Gilvan R. de , Nogueira Luís C. , Ivo Walane M.P. de M.
Published: November 2006

Realizaram-se testes de campo, com o objetivo de se caracterizar a variabilidade espacial da condutividade hidráulica (K0) num solo aluvial, na Estação Experimental da Embrapa Algodão, em São Gonçalo, Paraíba, em 19 pontos de uma área de 18 ha. As profundidades do fundo dos poços situaram-se entre 1,0 e 1,65 m, considerando-se que a profundidade projetável do sistema drenante se situa nessa faixa da maioria das áreas irrigadas do Nordeste brasileiro. A amplitude de variação obtida de K0 (0,02 a 1,71 m d-1) mostra-se como resultado comum da maioria dos solos aluviais, resultante de processos de evolução do solo estudado, da gênese e da complexidade geomorfológica.
Estatísticas sobre irrigação no Brasil segundo o Censo Agropecuário 1995-1996
Authors: Loiol Mardônio L. , Souza Francisco de
Published: November 2006

Neste trabalho utilizam-se dados do Censo Agropecuário 1995-1996, para se avaliar a irrigação no país, com relação à área irrigada, aos métodos utilizados e aos grupos de área, por região e por estado. A área irrigada no Brasil, de acordo com o Censo Agropecuário 1995-1996, é de 3,1 milhões de hectares, representando apenas 2,1% dos 146,8 milhões de hectares cultivados com lavouras permanentes, temporárias, pastagens e florestas. A região Sul apresenta a maior área irrigada, 1,1 milhão de ha, equivalente a 35% da área total irrigada. Em segundo lugar vem a região Sudeste com, aproximadamente, 30%; com 24% de toda a área irrigada no Brasil, o Nordeste ocupa a terceira posição seguido das regiões Centro-Oeste e Norte, que têm pouca expressão e, juntas, somam cerca de 11% do total. Nas regiões NE, SE e Sul, a irrigação predomina nos estabelecimentos cuja área é inferior a 1.000 ha. Diferentemente, nas regiões Norte e Centro-Oeste a irrigação é mais significativa nos estabelecimentos com área maior que 10.000 ha. O método de irrigação por superfície, continua a ser o mais utilizado no país (59%), nas regiões NE e Sul, com a aspersão prevalecendo nas demais regiões; a irrigação localizada representa a menor área.
Equilibrium adsorption of chlorophenols on granular activated carbon
Authors: Nelson Peter O. , Yang Maoyu
Published: November 2006

The adsorption of chlorinated phenols from aqueous solution on granular activated carbon was studied in batch reactors. Single‐component equilibrium adsorption data for the eight compounds in two concentration ranges at pH 7.0 and 30°C were fit well by both the Langmuir and the Freundlich equations. The adsorptive capacities at pH 7.0 increase from pentachlorophenol to trichlorophenols and are fairly constant from trichlorophenols to monochlorophenols. Equilibrium measurements were also conducted for 2,4,5‐trichlorophenol, 2,4‐dichlorophenol, and 4‐chlorophenol over a wide pH range. A surface complexation model has been proposed to describe the effect of pH on adsorption equilibria of chlorophenols on activated carbon. Activated carbon surface functional sites are divided into acidic and basic groups with which molecular and ionized forms of chlorophenols interact, respectively, and form two neutral complexes. The simulations of the model are in excellent agreement with the experimental data.
Recovery of s‐triazine herbicides and associated breakdown products from granular activated carbon using supercritical fluid extraction
Authors: Robertson Alan M. , Lester John N.
Published: November 2006

S‐triazine herbicides and associated breakdown products were recovered from granular activated carbon (GAC) using a dual pump supercritical fluid extraction (SFE) system capable of modifier addition. Analyte recovery was very low using supercritical carbon dioxide alone, was moderately improved by acetone modification in the static mode, and was significantly improved by dynamic acetone modification. Quantitative extraction of atrazine and simazine was achieved in 30 min using 50 mol% acetone in CO2, although recoveries for associated break‐down products (deethylatrazine and deethylsimazine) were limited to 70%. S‐triazine extraction rates were independent of the flow rate of the extracting fluid, indicating a significant interaction of s‐triazine molecules with active sites on the GAC matrix surface and a kinetic limitation to the desorption process. SFE was as precise as, and much faster than, Soxhlet extraction for the determination of these priority pollutants and was advantageous in terms of improved analyte recovery and reduced solvent and labour requirements.
Anaerobic pretreatment of hazardous waste leachates in publicly owned treatment works
Authors: Kupferle Margaret J. , Chen Tsaichu , Gallardo Vicente J. , Lindberg David E. , Bishop Paul L. , Safferman Steven I. , Bishop Dolloff F.
Published: November 2006

Feasibility studies have been completed for an anaerobic pretreatment system designed to treat hazardous waste leachates in publicly owned treatment works. The system was designed to mitigate many of the problems associated with conventional aerobic treatment of these wastes and other types of dilute waterborne hazardous wastes. In this new approach, a contact/sorption stage consisting of an expanded bed of granular activated carbon (GAC) with an attached anaerobic biomass was used as a pretreatment device after primary clarification before the aerobic treatment portion of the plant. This sorption stage was intended to reduce pass‐through of toxics, retaining them for subsequent treatment in a separate anaerobic stabilization reactor. The organic‐rich GAC/biomass bed from the sorption stage was exchanged with stabilized GAC biomass from the anaerobic stabilization stage, conserving the GAC in the system. Two 87‐L/d bench‐scale systems were operated for 332 days, one treating unspiked primary effluent and one treating primary effluent spiked with 5% landfill leachate and 14 hazardous organic compounds. In the spiked system, removals in the sorption stage were the highest for the aromatic compounds. Five of the six aromatics added were removed at over 95% and the sixth, phenol, had an 85% removal. Removals of chlorinated aliphatic compounds ranged from 52% for methylene chloride to 95% for trichloroethylene. Removals of phthalate compounds were approximately 60%. Removals of ketones ranged from 24% for acetone to 93% for methyl isobutyl ketone. Chemical oxygen demand removals remained at 40% to 50% throughout the year‐long study in both systems.
Evaluation of immobilized biomass beads for removing heavy metals from wastewaters
Authors: Spinti Mark , Zhuang Hanna , Trujillo Edward M.
Published: November 2006

Immobilized biomass beads, which consist of dried and ground sphagnum peat moss immobilized in a porous polysulfone matrix, effectively remove heavy metals from wastewaters under appropriate conditions. This paper examines the procedure for forming the beads and their performance in packed columns. The beads are produced by atomizing an organic dispersion into water, creating droplets that become solid through phase inversion. Increasing the relative biomass content gave slightly lower surface areas. Metal ion break through curves were obtained for metal ions from two actual acid mine drainage wastewaters. The selectivity of the beads for various cations was Fe > Al > Pb > Cu > Cd, Zn > Ca > Mn > Mg > Na. Capacity increases with initial pH of the column after regeneration. Bead titration tests indicate that the immobilized biomass beads have heterogeneous ionogenic adsorption sites. Experimental results also indicate that most of the magnesium removed from water by the immobilized biomass beads is adsorbed and exchangeable with potassium. Under the conditions used here, the immobilized biomass beads have a lower capacity than two commercially available ion exchange resins.
A proposed method for improving whole effluent toxicity data interpretation in regulatory compliance
Authors: Dhaliwal Bhupinder S. , Dolan Roger J. , Smith Robert W.
Published: November 2006

We describe three statistical models for assessing whole effluent toxicity data for National Pollutant Discharge Elimination System compliance purposes. The first model, on which the current regulatory approach is based, only considers intratest variation. The second and third models consider both intratest and intertest sources of variability. We perform a variance components analysis with reference toxicant data to show the relative magnitudes of the intratest and intertest variation. The results indicate that the third model, which is a mixed two‐way ANOVA design with test crossed with concentration, is the most appropriate model. With simulations, we show that when using the first statistical model instead of the more suitable third model, the actual Type‐1 error can exceed the nominal Type‐1 error by a large amount. This means that tests with the first model will tend to produce an excessive number of false indications of toxicity by chance alone. We present and demonstrate a statistical test, called the reliable toxicity detection level (RTDL), that is based on the third statistical model. The RTDL is compared with other statistical measures used to determine compliance to toxicity and chemical effluent limits.
Competition for substrate and space in biofilms
Authors: Zhang Tian Cheng , Fu Yun‐Cheng , Bishop Paul L.
Published: November 2006

Competition for substrate and space in biofilms was studied using a microelectrode technique and a micro‐slicing technique. Three different kinds of biofilms were cultured using laboratory‐scale, rotating drum biofilm reactors fed with synthetic wastewater. The measured concentration profiles provide direct experimental evidence of the competition in multispecies biofilms for substrates. Increases in organic loading or ammonium‐nitrogen loading cause more consumption of oxygen, which results in competition for oxygen between heterotrophs and nitrifiers. Even in a pure nitrification system, heterotrophs, supported by soluble microbial products or metabolic products, could exist in the nitrification biofilm. Nitrifiers, however, have difficulty existing in the heterotrophic biofilms, and their populations were always 4 or 5 orders lower than those of heterotrophs. It was found that the value of criterion for transition between oxygen and ammonium in nitrifying biofilms (SN/SDO) was between 0.77 and 1.2, and the value decreased with an increase of glucose loading. The competition for substrate in biofilms resulted in a stratified structure with non uniform spatial distributions of biofilm properties, such as density, porosity, and effective diffusivity. This stratified structure in turn affects the substrate transfer and substrate competition within the biofilm. It was found that a certain biofilm system may not have only one penetration depth, corresponding to the critical thickness, for the whole range of biofilm thicknesses.
Prevalence of Aeromonas spp. in surface waters
Authors: Bernagozzi Marta , Bianucci Fabrizio , Sacchetti Rossella
Published: November 2006

The quantity of Aeromonas spp. and Aeromonas hydrophila was determined in samples of fresh surface water, brackish, and seawater with different degrees of pollution, and their presence was compared with the classical indicators of water fecal pollution. Aeromonas spp. were isolated from all the water samples examined and their number, like that of Aeromonas hydrophila, was always higher than, and in some cases correlated with, that of fecal coliforms. The results obtained seem to confirm the opinion already expressed by other researchers regarding the importance of monitoring the presence of these bacteria to obtain more complete information on the degree of contamination of surface water.
Treatment of 2,4‐dinitrotoluene using a two‐stage system: Fluidized‐bed anaerobic grangular activated carbon reactors and aerobic activated sludge reactors
Authors: Berchtold Sandra R. , VanderLoop Sarah L. , Suidan Makram T. , Maloney Stephen W.
Published: November 2006

Continuous‐flow anaerobic fluidized‐bed granular activated carbon bioreactors were used to treat 2,4‐dinitrotoluene (2,4‐DNT), a compound used in primary propellant production. A synthetic wastewater solution containing 2,4‐DNT, ethanol, mineral ether, and a carbonate buffer and another solution containing growth nutrients and vitamins were fed to each of the two bioreactors. The influent ethanol concentrations were varied to determine the effect of ethanol concentration on the extent of 2,4‐DNT degradation. The anaerobic bioreactors, when operated under methanogenic conditions with a primary substrate, were able to transform the 2,4‐DNT into 2‐amino‐4‐nitrotoluene (2‐A‐4‐NT), 4‐amino‐2‐nitrotoluene (4‐A‐2‐NT), 2,4‐diaminotoluene (2,4‐DAT), and trace amounts of toluene. During stable operation, for the range of non‐zero influent ethanol concentrations evaluated in this study, the majority of the products were identified as 2,4‐DAT. Batch activated sludge reactors were used to examine the fate of 2,4‐DAT under aerobic conditions. 2,4‐DAT (16 mg/L) were mineralized within 9 hours, indicating that a two‐stage system may be an effective 2,4‐DNT treatment strategy.
Effect of operating variables on nitrification rates in trickling filters
Authors: Parker Denny , Lutz Mike , Andersson Bengt , Aspegren Henrik
Published: November 2006

A 2‐year pilot study was conducted by the City of Malmö, Sweden, to determine the maximum capacity of existing trickling filters when converted from carbonaceous duty to nitrification duty. Operating variables examined included a comparison of alternating two‐stage to single‐stage operation, flushing intensity, and predator control techniques. Distributor speed control had only a small effect on nitrification efficiency, and motorized distributors are not required in this application. Two‐stage operation in an alternating ode provided for higher nitrification rates and lower effluent ammonia values than in single‐stage operation. A nitrification model was used to analyze reaction rate data. The analysis showed that alternating two‐stage operation mitigated the suppressing effect of influent suspended solids, resulting in enhanced nitrification rates. The filter macrofauna were dominated by worms rather than filter flies, so that regular filter flooding did not enhance nitrification rates.
Mineral‐catalyzed Fenton‐like oxidation of sorbed chlorobenzenes
Authors: Watts Richard J. , Jones Alexander P. , Chen Ping‐Hung , Kenny Allen
Published: November 2006

The oxidation of 1,3,5‐trichlorobenzene, 1,2,3,4‐tetrachlorobenzene, pentachlorobenzene, and hexachlorobenzene sorbed on hematite (α‐Fe2O3), a naturally occurring soil mineral, by catalyzed hydrogen peroxide was investigated using the hematite as the sole source of the iron catalyst. Partitioning of the chlorobenzenes onto the hematite was documented and essentially each of the chlorobenzenes was initially found in the sorbed state. Subsequent desorption measurements using gas‐purge methodology showed that the rate of chlorobenzene desorption decreased as a function of chlorine substitution. The first‐order rate constants for the desorption of 1,3,5‐trichlorobenzene, 1,2,3,4‐tetrachlorobenzene, and pentachlorobenzene were 0.091, 0.051, and 0.029 hr−1, respectively. Hexachlorobenzene desorption was undetectable over 144 hr. Hematite‐chlorobenzene slurries were treated with H2O2 concentrations ranging from 0.1 to 5% at pH 3. The degradation of 1,3,5‐trichlorobenzene, 1,2,3,4‐tetrachlorobenzene, and pentachlorobenzene using H2O2 concentrations ≤1% proceeded at rates less than their corresponding rates of desorption, suggesting that desorption controlled the rates of oxidation. When H2O2 concentrations ≥2% were used, the degradation rates of the three lower chlorobenzenes exceeded the rates of desorption suggesting that oxidation was occurring, at least in part, in the sorbed state. Hexachlorobenzene was not degraded by H2O2 concentrations ≤5%. Hydroxyl radical generation rates were not significantly different in all of the hematite‐catalyzed systems, indicating that surface catalysis mechanisms were saturated with respect to H2O2 (i.e., were characterized by 0‐order kinetics), even at the lowest H2O2 concentrations. The data show that sorption significantly affects rates of mineral‐catalyzed H2O2 oxidations, and that different mechanisms (e.g., surface‐catalyzed oxidation) may be occurring at H2O2 concentrations ≥2%.
Assessment of in situ solvent extraction interrupted pumping for remediation of subsurface coal tar contamination
Authors: Ghosh Rajat S. , Saigal Sunil , Dzombak David A.
Published: November 2006

In situ solvent extraction involving continuous injection‐recovery of solvent‐water solutions has been proposed for removal of coal tar and other nonaqueous phase liquids from the subsurface environment. A modified in situ solvent extraction technique involving an interrupted injection‐recovery procedure was examined with a view toward improved recovery efficiency. Design of an interrupted pumping process for in situ solvent extraction was examined, and an initial comparison of the interrupted pumping process with the continuous pumping process was performed by simulation. A two‐dimensional solute transport model was modified to incorporate the mass transfer processes involved during the shut‐in and continuous flow periods. This model was thereafter used to simulate application of the interrupted and the continuous pumping processes at a hypothetical manufactured gas plant site. The predicted coal‐tar recovery rates did not differ significantly for the interrupted and continuous pumping processes, but the interrupted pumping process was consistently more efficient in terms of solvent requirements and pumping duration needed. It appears that interrupted pumping offers somewhat faster mass removal rates and somewhat reduced pumping requirements to reach a particular remediation goal.
Minimizing costs of activated‐sludge systems
Authors: Pincince Albert B. , Braley Brandon G. , Sangrey Karla H. , Reardon Roderick D.
Published: November 2006

The concentration of mixed liquor suspended solids (MLSS) in aeration tanks affects the required aeration tank volume and the surface area required for secondary settling. As the MLSS increases, the required aeration volume decreases, resulting in decreased construction costs; however, because of solids‐flux limitations, the required clarifier surface area increases with an increase in MLSS, and the cost for clarifiers increases. The total cost of an activated‐sludge system is a minimum at an intermediate MLSS concentration. Previous investigators have shown that the MLSS at which total system cost is minimum depends on sludge settling properties. The optimum MLSS is higher for sludge that settles well than for sludge that settles poorly. This paper demonstrates for the first time that the mass of biological solids that needs to be maintained in the aeration tanks affects the optimum MLSS. Plants with a high mass of biological solids—such as with nitrification or biological nutrient removal—should be designed for higher MLSS than plants with low biological solids. Similarly, plants without primary settling should be designed for higher MLSS than plants with primary settling. The MLSS value at the minimum system cost can be determined using curves for costs of aeration tanks and secondary settling. For plants with multiple units (for example, the Deer Island Treatment Plant in Boston, Mass.), where the cost of each additional aeration tank or secondary clarifier is relatively constant, the impact of additional secondary clarifiers can be assessed in combination with the need for fewer aeration tanks. The ideal MLSS is specific to a particular combination of flows, waste strengths, and cost setting, but the optimum MLSS can be readily determined for particular cases.
Reduction of sampling time in tracer studies
Authors: Agunwamba Jonah C.
Published: November 2006

An approach of evaluation of dispersion number has been suggested. Unlike the existing method, which is based on fixed‐point continuous monitoring until the tracer concentration has been reduced to negligible concentration, the new approach assumes that sampling takes place at various equidistant points along the pond or channel simultaneously or at variable times. The new approach was illustrated with laboratory data and gave results 0.9–3.3 higher than those obtained with the conventional Levenspiel and Smith fixed‐point continuous‐monitoring method. Its advantages over the existing methods, which include savings in time, economy, convenience, and flexibility, were also discussed. The Levenspiel and Smith method was employed in analysis and comparison.
Recovery of cyanide from wastewater using gas‐filled membrane absorption
Authors: Shen Zhisong , Huang Jane , Qian Guofen
Published: November 2006

To commercialize the application of gas‐filled membrane absorption (GFMA) in the recovery of cyanide from wastewater, the minimization of desired membrane area, membrane fouling, and other aspects were explored. The influences of operation parameters on the mass transfer coefficient is the focus of this study, which includes temperature, velocity, pH, and concentration. The concept of GFMA, the mass transfer resistance, the mass transfer equation, and other theoretical aspects are also introduced briefly. Experimental results show that the GFMA has good prospects in the commercialization of cyanide recovery.
Solid‐phase extraction for oil and grease analysis
Authors: Lau Sim‐Lin , Stenstrom Michael K.
Published: November 2006

Conventional oil and grease analysis that involves liquid‐liquid extraction (LLE) has many disadvantages, which include poor reproducibility, emulsion formation, large solvent usage, and loss of volatile and semivolatile compounds during evaporation of the solvent. Therefore, an alternative method using octadecyl siloxane (C18) solid‐phase extraction (SPE) columns was developed to overcome these analytical problems. The amount of the solvent was reduced and more reproducible results were obtained using this C18 SPE method. The time required for analysis is approximately the same for both methods. Higher recovery of semivolatile compounds also was obtained. The proposed C18 SPE method was also found to be comparable to those obtained from commercially available columns.
Waste activated sludge production of the enhanced biological phosphorus removal process
Authors: Jardin Norbert , Pöpel H. Johannes
Published: November 2006

The effect of the enhanced biological phosphorus removal process (EBPR) on waste activated sludge (WAS) production and the type of phosphorus storage were investigated in two continuous‐flow activated‐sludge systems in a semitechnical scale. One of the plants was operated with the A/O® process, whereas the other plant was operated in a conventional, fully aerobic mode and served as a control. By monitoring the elementary composition of the activated‐sludge solids in plant II and by using phosphorus fractionations, it was found that nearly all of the enhanced phosphorus removal was due to storage as polyphosphate (poly‐P). The additional uptake of phosphorus resulted in an increase of the inorganic sludge mass, which was determined to be 3.05 g suspended solids (SS)/g P using the results of the measurements of the nonvolatile solid fraction. This value was confirmed experimentally by the measurement of the difference between the WAS production of plant I and plant II. Based on the specific WAS production, an additional dry solids production of 3.14 g SS/g P was calculated. No indications for a significant difference of the organic sludge production between both plants were found, although the organic WAS production was slightly higher in experimental periods with a relatively high phosphorus content of the activated‐sludge solids of plant II.
Separation Preconcentration Method for Platinum and Rhodium from Environmental Samples Using a Chelating Resin
Authors: Bosch Ojeda C. , Sánchez Rojas F. , Cano Pavón J.M.
Published: November 2006

A method of determining trace levels of platinum and rhodium in different samples was investigated. The method involves separation and preconcentration of the platinum and rhodium from the matrix by flow injection (FI) on‐line coupled with electrothermal atomic absorption spectrometry (ETAAS) with Zeeman effect background correction. Platinum and rhodium were adsorbed on a microcolumn packed with 1,5‐bis(di‐2‐pyridyl)methylene thiocarbohydrazide immobilized on silica gel (DPTH‐gel). The sorbed metals were directly eluted with nitric acid into the graphite furnace and determined by AAS.
Bracciano's Lake Waters: An Experimental Survey on the Surface Layer Pollution
Authors: Catalani Alessia , Medici Franco , Rinaldi Gilberto
Published: November 2006

The chemical and trophic conditions of the surface waters of the lake Bracciano, near Roma, have been investigated all through the year 2005. Electrical conductivity, pH, alkalinity, hardness, total nitrogen, phosphorus content, chloride, fluoride and sulphate ions were measured. The results were compared with similar analyses formerly carried out by different authors, to achieve a right evaluation of the actual quality of the surface waters of the lake Bracciano all over the year 2005.
Measurements and CFD simulations of gas holdup and liquid velocity in novel airlift membrane contactor
Authors: Jajuee Babak , Margaritis Argyrios , Karamanev Dimitre , Bergougnou Maurice A. , Karimian S. A. Mohsen
Published: November 2006

Liquid velocity and gas holdup were measured in a 690L pilot‐scale rectangular airlift contactor, divided into aerated and nonaerated sections by two vertical rectangular polyester textile membranes. Horizontal flow through the porous membranes complicates flow fields to such an extent that conventional models cannot predict thoroughly velocity profile in the contactor. Experimental data obtained from laser doppler velocimetry (LDV) method were compared with numerical finite volume method (FVM), in order to determine the velocity profile in the downcomer zone of the contactor. In formulating the data, a realistic set of boundary conditions was implemented in the numerical method, resulted in satisfactory agreement between theory and experiment. The effects of the distance between the rectangular membranes and air bubble size on the velocity profile were also studied. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Time‐resolved chemiluminescence study of the TiO2 photocatalytic reaction and its induced active oxygen species
Authors: Min Lingyue , Wu Xing‐Zheng , Tetsuya Shimada , Inoue Haruo
Published: November 2006

The time‐resolved chemiluminescence (CL) method has been applied to study the TiO2 photocatalytic reaction on a µs–ms timescale. The experimental set‐up for time‐resolved CL was improved for confirmation of the unique luminol CL induced by the photocatalytic reaction. The third harmonic light (355 nm) from an Nd:YAG laser was used for the light source of the TiO2 photocatalytic reaction. Luminol CL induced by this reaction was detected by a photomultiplier tube (PMT) and a preamplifier was used for amplifying the CL signal. Experimental conditions affecting the photocatalytically induced CL were discussed in detail. The involvement of active oxygen species such as ·OH, O2·− and H2O2 in the CL was examined by adding their scavengers. It is concluded that ·OH was greatly involved in the CL on a µs–ms timescale, especially in time periods <100 µs after illumination of the pulse laser. On the other hand, CL generated by O2·− began to increase after 100 µs and became dominant after 2.5 ms. A small part of the CL might be generated by H2O2 on the whole µs–ms timescale. A CL reaction mechanism related with ·OH and dissolved oxygen was proposed to explain the photocatalytically induced luminol CL on a µs–ms timescale, especially in periods <100 µs. Copyright © 2006 John Wiley & Sons, Ltd.
Pentazocine monitoring in rat hair and plasma by HPLC‐fluorescence detection with DIB‐Cl as a labelling reagent
Authors: Wada Mitsuhiro , Kurogi Rie , Kaddoumi Amal , Nakashima Mihoko N. , Nakashima Kenichiro
Published: November 2006

Pentazocine (PZ) in rat hair and plasma was determined by HPLC–fluorescence detection with 4‐(4,5‐diphenyl‐1H‐imidazol‐2‐yl)benzoyl chloride (DIB‐Cl) as a labelling reagent and cyclazocine (CZ) as an internal standard (IS). PZ and IS extracted from hair or plasma sample were derivatized with DIB‐Cl and the resulted solution was cleaned up with solid phase extraction. The isocratic separation of DIB‐PZ and ‐CZ within 20 min could be achieved by a Wakopak Handy‐ODS column (250 × 4.6 mm i.d.) using a mobile phase composed of 0.1 mol/L acetate buffer (pH 6.2):acetonitrile (25:75, v/v). The detection limits of PZ at a signal‐to‐noise ratio of 3 for rat hair and plasma were 0.18 ng/mg and 0.57 ng/mL, respectively. Reproducible and precise results could be obtained by an IS method with RSD values less than 6.6% for within‐ and between‐day measurements. The method was successfully applied for the monitoring of PZ levels in Zucker rat hair and plasma samples after a single administration of 25 mg/kg PZ. Moreover, incorporation rates of PZ into black and white hair of Zucker rat were evaluated. Copyright © 2006 John Wiley & Sons, Ltd.
HPLC determinations of enantiomeric ratios
Authors: Wipf Peter , Werner Stefan , Twining Leslie A. , Kendall Christopher
Published: November 2006

Evaporative light‐scattering detection (ELSD) is widely applied in the HPLC analysis of organic compounds lacking a UV chromophore. However, this detection method is generally unsuitable for determination of enantiomeric ratios (er). The er calculated from a UV trace and an ELS trace of the same compound differs significantly. Because of the nonlinear concentration response of the ELS detector, a compound with an er of 95:5 appears to be enantiomerically pure by ELS detection. It is possible to obtain a calibration curve and to calculate a correction factor, but this procedure is time consuming and therefore not very practical for routine analyses. In contrast, a charged aerosol detector allows a very accurate determination of the enantiomeric ratios. Like the ELS detection, the CA detection is independent of the chromophore properties of the substrate. Therefore, we recommend the use of CA instead of ELS detection for determination of the enantiomeric ratios of non‐UV active compounds. Chirality, 2006. © 2006 Wiley‐Liss, Inc.
Fast methods of enantiopurity determination for the Soai reaction: Towards a general enantioenrichment detector?
Authors: Welch Christopher J. , Biba Mirlinda , Sajonz Peter
Published: November 2006

The Soai reaction system possesses a remarkable combination of characteristics (enantioselective autocatalysis, strong positive nonlinearity leading to asymmetric amplification, ability to be triggered by wide variety of exogenous enantioenriched materials) that make it a potential starting point for a generalized detector for enantioenrichment. In this study we apply standard approaches used in pharmaceutical process research to the problem of developing a rapid method for analysis of the enantiopurity of the Soai reaction product. Several methods for rapid analysis (<1 min per sample) are described, including an approach using chiral supercritical fluid chromatography (SFC) and an approach using achiral chromatography with circular dichroism (CD) detection. Some thoughts on incorporation into a device for generalized enantioenrichment detection are presented. Chirality, 2006. © 2006 Wiley‐Liss, Inc.
Theoretical Determination of the Vibrational Raman Optical Activity Signatures of Helical Polypropylene Chains
Authors: Lamparska Ewa , Liégeois Vincent , Quinet Olivier , Champagne Benoît
Published: November 2006

Raman and vibrational Raman optical activity (VROA) spectra of helical conformers of polypropylene chains are simulated using ab initio methods to unravel the relationships between the vibrational signatures and the primary and secondary structures of the chains. For a polypropylene chain containing three units, conformational effects are shown to lead to more acute signatures for VROA than for Raman spectra. In addition to regular polypropylene chains, which can display right and left helicities with the same probability, chirality and therefore helicity are enforced by substituting one chain end with a phenyl group. The simulations predict that the threefold helical structures, which correspond to (TG)N conformations of the backbone, have a specific VROA backward signature in the form of an intense couplet around 1100 cm−1. This couplet is associated with collective wagging and twisting motions, while most of its intensity comes from the anisotropic invariants combining normal coordinate derivatives of the electric dipole–electric dipole polarizability and of the electric dipole–magnetic dipole polarizability. A similar signature has already been found in model helical polyethylene chains, whereas it is very weak in forward VROA.
Cover Picture: Combined AFM and Two‐Focus SFCS Study of Raft‐Exhibiting Model Membranes (ChemPhysChem 11/2006)
Authors: Chiantia Salvatore , Ries Jonas , Kahya Nicoletta , Schwille Petra
Published: November 2006

The cover picture shows the simultaneous application of atomic force microscopy (AFM), laser scanning microscopy (LSM) and two‐focus scanning fluorescence spectroscopy (SFCS) on a model membrane of biological relevance. While structural data is provided by the nanoscopic spatial resolution of the AFM, 2‐focus SFCS can be used to probe the diffusion of proteins and lipids in distinct microdomains of the lipid bilayer. In the article on page 2409, S. Chiantia and J. Ries et al. show that the lateral organization of lipid and proteins can be reliably probed by the combined approach of these techniques.
Prolonged exposure to homocysteine results in diminished but reversible pancreatic β‐cell responsiveness to insulinotropic agents
Authors: Patterson Steven , Scullion Siobhan M. J. , McCluskey Jane T. , Flatt Peter R. , McClenaghan Neville H.
Published: November 2006

Background

Plasma homocysteine levels may be elevated in poorly controlled diabetes with pre‐existing vascular complications and/or nephropathy. Since homocysteine has detrimental effects on a wide diversity of cell types, the present study examined the effects of long‐term homocysteine exposure on the secretory function of clonal BRIN‐BD11 β‐cells.

Methods

Acute insulin secretory function, cellular insulin content and viability of BRIN‐BD11 cells were assessed following long‐term (18 h) exposure to homocysteine in culture. RT‐PCR and Western blot analysis were used to determine the expression of key β‐cell genes and proteins. Cells were cultured for a further 18 h without homocysteine to determine any long‐lasting effects.

Results

Homocysteine (250–1000 µmol/L) exposure reduced insulin secretion at both moderate (5.6 mmol/L) and stimulatory (16.7 mmol/L) glucose by 48–63%. Similarly, insulin secretory responsiveness to stimulatory concentrations of alanine, arginine, 2‐ketoisocaproate, tolbutamide, KCl, elevated Ca2+, forskolin and PMA, GLP‐1, GIP and CCK‐8 were reduced by 11–62% following culture with 100–250 µmol/L homocysteine. These inhibitory effects could not simply be attributed to changes in cellular insulin content, cell viability, H2O2 generation or any obvious alterations of gene/protein expression for insulin, glucokinase, GLUT2, VDCC, or Kir6.2 and SUR1. Additional culture for 18 h in standard culture media after homocysteine exposure restored secretory responsiveness to all agents tested.

Conclusion

These findings suggest that long‐term exposure to high homocysteine levels causes a reversible impairment of pancreatic β‐cell insulinotropic pathways. The in vivo actions of hyperhomocysteinaemia on islet cell function merit investigation. Copyright © 2007 John Wiley & Sons, Ltd.
Associations among family‐of‐origin food‐related experiences, expectancies, and disordered eating
Authors: Annus Agnes M. , Smith Gregory T. , Fischer Sarah , Hendricks Megan , Williams Suzannah F.
Published: November 2006

Objective:

The study reported here integrates research on family‐of‐origin learning experiences and adult eating/thinness expectancies in the study of risk for eating disordered behavior.

Method:

A sample of women manifesting a wide range of eating disordered behaviors (n = 66) were compared in their retrospective reports of family learning, current eating and dieting expectancies, and current eating disordered behaviors.

Results:

History of food‐related teasing from friends and family, negative maternal modeling, and friends' criticism of eating all related to both adult disordered behavior and adult eating and thinness expectancies. Tests of mediation supported the putative mediation by expectancies of the relationships between early experiences and adult disordered behavior.

Conclusion:

Family‐of‐origin learning experiences may influence adult eating disordered behavior by contributing to the formation of expectancies for reinforcement from eating and from thinness. © 2006 by Wiley Periodicals, Inc. Int J Eat Disord 2006
Synthesis of 2‐[11C]methoxy‐3,17β‐estradiol to measure the pharmacokinetics of an antitumor drug candidate, 2‐methoxy‐3,17β‐estradiol
Authors: Mun Jiyoung , Voll Ronald J. , Goodman Mark M.
Published: November 2006

2‐Methoxy‐3,17β‐estradiol, an endogenous estrogen metabolite, showed cytotoxicity in various cancer cell lines and also has antiangiogenic and proapoptotic activities. Clinical I and II trials of 2‐methoxy‐3,17β‐estradiol for multiple myeloma, advanced solid tumors, metastatic breast and prostate cancer are underway. We prepared 2‐[11C]methoxy‐3,17β‐estradiol to measure the pharmacokinetics and organ distribution of 2‐methoxy‐3,17β‐estradiol in clinical trials. 2‐[11C]Methoxy‐3,17β‐estradiol was synthesized from a precursor, 2‐hydroxy‐3,17β‐O‐bis(methoxymethyl)estradiol, in two steps with over 99% radiochemical purity. The overall reaction time was 45 min and the decay‐corrected radiochemical yield was 32.9%. The distribution coefficient (logP7.4) of 2‐[11C]methoxy‐3,17β‐estradiol at pH 7.4 was measured as 2.95. Copyright © 2006 John Wiley & Sons, Ltd.
A tale in molecular recognition: the hammerhead ribozyme
Authors: Westhof Eric
Published: November 2006

A new crystal structure of the hammerhead ribozyme demonstrates the influence of peripheral tertiary contacts on the local conformations around the active site. This structure resolves many conflicting results obtained on reduced systems. Copyright © 2006 John Wiley & Sons, Ltd.
Schichtbildung beim Feuerverzinken zwischen 435°C und 620°C in konventionellen Zink‐Schmelzen – eine ganzheitliche Darstellung
Authors: Thiele M. , Schulz W.‐D. , Schubert P.
Published: November 2006

Für vier typische Baustähle mit unterschiedlichem Silizium‐Gehalt sowie Emaillierstahl wird das Schichtwachstum und die Struktur der sich bildenden Überzüge in Abhängigkeit von der Tauchdauer, der Schmelztemperatur und der thermischen Vorbehandlung untersucht. Die Ergebnisse werden unter Bezug auf die experimentell bestimmte Wasserstoffeffusion der Stähle diskutiert. Für den Temperaturbereich von 435°C bis 620°C wird eine Übersicht vorgestellt, die für den Praxisbetrieb im Normal‐ und Hochtemperaturbereich anwendbar ist.
Investigations on the protection effect of filling materials for post‐tensioning systems under construction conditions
Authors: Mietz J. , Burkert A. , Burkert A. , Eich G.
Published: November 2006

About the long‐term protection behaviour of corrosion protection materials (filling materials) for prestressed systems under critical environmental conditions is only little known. The corrosion protection effect is usually based on theoretical considerations and is proven by short‐term tests. The selection of the different products is mainly made according to economical or workability criteria. In a research project the barrier effect of different commercial corrosion protection materials (waxes as well as oil‐based greases) against water, their tendency for undercutting as well as their additional corrosion protection effect were investigated. The exposure tests were carried out with non‐stressed as well as stressed prestressing steel specimens which were subjected to critical conditions (condensed water, artificial soil solution, direct soil contact). Parallel to these long‐term exposure tests the applicability of different electrochemical techniques and their significance with respect to testing the corrosion protection ability and water absorption was evaluated. Within the project a suitable method for simple testing the performance of corrosion protection materials under real conditions was developed. By means of a small compact cell submicroscopical reactions of the used sensors could be measured. The high sensitivity of this measuring technique enables the detection of degradation processes at thin protection layers.
Interest in participating in clinical research: A study of essential tremor patients
Authors: Louis Elan D. , Applegate LaKeisha M. , Rios Eileen
Published: November 2006

Enrolling essential tremor (ET) patients in clinical research can be challenging. Investigators can maximize recruitment by targeting patient subgroups with greater interest in participation. Nothing has been published on factors that are associated with higher levels of interest in participation. The objective of this study was to identify factors associated with higher levels of interest in participating in clinical research on ET. A total of 149 ET patients were questioned about level of interest in participating in future research. Two questions were used, although one was of primary interest. Interest was rated from 0 to 10 (maximal). Data were collected on demographic factors, family history, and tremor‐related disability. Tremor severity was assessed. The mean level of interest was 8.0 ± 2.3. Level of interest was not related to age of tremor onset, tremor duration, tremor severity, extent of tremor‐related disability, or use of tremor medication. Level of interest was related to family history of tremor (P < 0.05), concern that other family members might develop tremor (P < 0.05), >2 versus 0 live births in women (P < 0.05), the view that the tremor worsens with age (P < 0.05), and presence of head tremor (P = 0.05). A variety of factors were identified that were associated with greater interest in participating in clinical research. These observations should be assessed in additional patient samples. Investigators may use our observations to identify and target patients for clinical trials and other research. © 2006 Movement Disorder Society