Objetivo: O objetivo deste estudo foi avaliar se o uso de uma solução cristaloide balanceada induz menos alterações metabólicas do que o cloreto de sódio 0,9% em crianças submetidas à ressecção de tumor cerebral. Desenho: Estudo fase II, unicêntrico, de superioridade, randomizado e controlado, realizado no Instituto de Oncologia Pediátrica da Universidade Federal de São Paulo, Brasil. População: crianças com idade entre 6 meses e 12 anos submetidas à ressecção de tumor cerebral. Intervenção: O uso de uma solução cristaloide balanceada durante e após (por 24 horas) ressecção de tumor cerebral foi comparado ao uso de cloreto de sódio 0,9%. Eletrólitos séricos e gasometria arterial foram coletados em três momentos: antes da cirurgia (basal); após a cirurgia [pós-operatório imediato (POI)]; e no primeiro dia pós-operatório (1º DPO). Desfecho primário: O desfecho primário deste estudo foi a variação do cloro sérico (pós-préop Cl), definida como a diferença absoluta entre as concentrações plasmáticas medidas no POI e antes da cirurgia. Desfechos secundários: Como desfechos secundários, foram avaliadas as variações (pós-préop) dos outros eletrólitos e do excesso de bases (BE); a incidência de acidose hiperclorêmica; e o escore de relaxamento cerebral (ERC), avaliado pelo neurocirurgião por meio de escala de 4 pontos. Resultados: 53 pacientes foram incluídos no estudo e randomizados; 27 receberam solução balanceada (grupo SB) e 26, cloreto de sódio 0,9% (grupo NaCl 0,9%). O pós-préop Cl mediano foi significativamente menor no grupo SB [0 (-1,0; 3,0)] do que no grupo NaCl 0,9% [6 (3,5; 8,5)], p < 0,01. O pós-préop BE mediano foi menor [-0,4 (-2,7; 1,3) versus -4,4 (-5,0; -2,3), p < 0,01] e acidose hiperclorêmica menos frequente (4% versus 67%, p < 0,01) no grupo SB do que no grupo NaCl 0,9%. O ERC foi comparável entre os grupos. Conclusão: Em crianças submetidas à ressecção de tumor cerebral, o uso de solução cristaloide balanceada reduziu a variação do cloro sérico comparado ao uso de cloreto de sódio 0,9%. Esses achados respaldam o uso de soluções balanceadas em crianças submetidas à ressecção de tumor cerebral. Registro no Clinical Trials: NCT NCT02707549 / Objective: The aim of this study was to determine if the use of a balanced crystalloid induces less metabolic derangements than 0.9% saline solution in children undergoing brain tumor resection. Design: Phase II, single center, superiority, randomized and controlled trial performed at Instituto de Oncologia Pediátrica, Universidade Federal de São Paulo, São Paulo, Brazil. Population: Pediatric patients (age range, 6 months to 12 years) undergoing brain tumor resection. Intervention: Use of a balanced crystalloid solution during and after (for 24 h) brain tumor resection was compared to saline 0.9%. Serum electrolyte and arterial blood gas analyses were performed before surgery (baseline), after surgery, and at postoperative day 1. Primary outcome: The primary trial outcome was the preoperative to postoperative variation in serum chloride (post-preop Cl) measured as the absolute difference between \"after surgery\" and baseline plasma concentrations. Secondary outcomes: As secondary outcomes, we measured the post-preop of other electrolytes and base excess (BE); hyperchloremic acidosis incidence; and the brain relaxation score, a four-point scale evaluated by the surgeon for assessing brain edema. Results: Fifty-three patients were included in the study; twenty-seven were randomized to receive a balanced crystalloid (balanced group) and twenty-six were randomized to receive 0.9% saline solution (saline group). The median post-preop Cl (mmol l-1) was significantly lower in the balanced [0 (-1.0; 3.0)] than in the saline group [6 (3.5;8.5); p < .01]. Median post-preop BE (mmol l-1) was lower [-0.4 (-2.7; -1.3) versus -4.4 (- 5.0; -2.3); p < .01] and hyperchloremic acidosis less frequent (4% versus 67%; p < .01) in the balanced group than in the saline group. Brain relaxation score was comparable between groups. Conclusions: In children undergoing brain tumor resection, balanced crystalloid solution infusion reduced variation in serum chloride. These findings support the use of balanced crystalloid solutions in children undergoing brain tumor resection

<div>Halogen chemistry in the Arctic boundary layer catalytically destroys O3 and impacts the chemical lifetimes of hydrocarbons, the HOx-NOx cycle, and atmospheric mercury. While many advances have been made in the last several decades in understanding the sources, sinks, and recycling pathways of halogens in the Arctic there are still many unknowns. Previous studies have shown that Br2, BrCl and Cl2 are produced photochemically in the Arctic tundra snowpack, but the magnitude of this production is still poorly understood. Additionally, while there have been suggestions that the tundra snowpack should also produce I2, there have been no previous measurements of I2 in the Arctic. The lack of measurements of the halogen production capacity of Arctic snowpacks has left the community to rely on one-dimensional modeling to estimate the impact of snowpack-derived halogen chemistry on the Arctic atmosphere. Because modeling is inherently dependent on understanding recycling mechanisms, mixing processes, and sinks this leaves the effect of halogens on atmospheric chemistry in the Arctic highly uncertain.</div><div><br></div><div>This work describes efforts to address these uncertainties through measurements made during two field campaigns in Utqiaġvik (formerly Barrow), Alaska in January – February 2014, and February – May 2016. The first measurements of I2 in the Arctic, both in the snowpack interstitial air, and in the air above the snowpack demonstrate that iodine chemistry is active in the Arctic atmosphere, and that I2 is produced photochemically in the tundra snowpack. The effects of active iodine chemistry on both O3 and bromine chemistry is examined through zero- and one dimensional modeling. The first speciated measurements of snowpack phase iodine reveal that much like previous reports of iodine enriched aerosols, the Arctic snowpack is highly enriched in iodine. Vertical profiles of I- in the snowpack suggest that there is a consistent, non-radiation dependent source of iodine to the Arctic environment. It seems likely that this source is transport of iodine-enriched aerosols from the mid-latitudes. However, unlike the Antarctic, and previous</div><div>observations in the mid-latitudes, most Arctic snowpack phase iodine is inorganic, which may contradict transport from the mid-latitudes as a source. One-dimensional modeling was also utilized, in conjunction with the first vertical profile measurements of Br2 and Cl2 between 1 and</div><div>7 m above the snowpack surface to examine the community’s understanding of recycling mechanisms, mixing, sources, and sinks of halogens in the Arctic Atmosphere.</div>

Made available in DSpace on 2016-12-23T14:04:32Z (GMT). No. of bitstreams: 1 Alexandre Demo Agrizzi.pdf: 7003943 bytes, checksum: 32fa12e406ceb8e9b8ef241ea1ee79ed (MD5) Previous issue date: 2011-02-25 / O cloro tem sido utilizado como principal pré-oxidante da matéria orgânica, inativando microrganismos patogênicos que vivem em águas naturais há mais de cem anos. A matéria orgânica encontrada em mananciais superficiais contém substâncias húmicas que podem reagir com o cloro, gerando compostos orgânicos halogenados potencialmente cancerígenos, destacando-se os trialometanos. Os principais trialometanos que se formam são o clorofórmio, o bromodiclorometano, o dibromoclorometano e o bromofórmio, e, a soma das concentrações destes quatro subprodutos é denominada trialometanos totais. Nas estações de tratamento de água (ETAs), a etapa de pré-oxidação com o cloro contribui significativamente para a formação desses compostos. A presente pesquisa teve como objetivo avaliar a formação de trialometanos após o tratamento convencional de água a partir da simulação de quatro rotas distintas em ensaios de bancada (jarteste), além de amostras retiradas diretamente das ETAs envolvidas no estudo. Os trialometanos foram quantificados por cromatografia gasosa com detector de captura de elétrons. Foram coletadas amostras de água bruta de dois mananciais do estado do Espírito Santo (Rio Jucu e Rio Sahy), com cor, absorvância em 254 nm e turbidez diferentes. Foram testados dois oxidantes nas análises: o cloro (na forma de hipoclorito de cálcio) e o permanganato de potássio. Os resultados obtidos mostraram que a formação de trialometanos foi menor quando as amostras de água foram tratadas com permanganato de potássio na etapa de pré-oxidação, quando comparadas com as amostras tratadas com cloro. Resultado semelhante ocorreu no potencial de formação de trialometanos de 24 horas. Em relação ao potencial de formação de sete dias, ambos mananciais mostraram ser capazes de formar compostos precursores dos trialometanos. Concentrações de trialometanos acima do limite permitido pela Portaria do Ministério da Saúde nº 518 (2004) foram detectadas somente nas amostras de água tratada do Rio Sahy / Chlorine has been used as the main pre-oxidation of organic matter, inactivating pathogenic microorganisms that live in fresh water for over one hundred years. The organic matter found in surface waters containing humic substances that can react with chlorine, generating potentially carcinogenic halogenated organic compounds, especially trihalomethanes. The main trihalomethanes that are formed are chloroform, bromodichloromethane, bromoform and the dibromochloromethane, and the sum of the concentrations of these four products is called total trihalomethanes. In water treatment plants (WTP), the stage of pre-oxidation with chlorine significantly contributes to the formation of these compounds. This research aimed to evaluate the formation of trihalomethanes after conventional treatment of water from the simulation of four different routes in bench tests (Jar-test), and specimens removed from the water treatment plants in the study. The trihalomethanes were quantified by gas chromatography with electron capture detector. Samples were collected from raw water from two springs of the state of Espirito Santo (Jucu and Sahy River), with different color, absorbance at 254 nm and turbidity. Two Oxidants were tested in analyses: chlorine (as calcium hypochlorite) and potassium permanganate. The results showed that the formation of trihalomethanes was lower when the water samples were treated with potassium permanganate in the pre-oxidation, when compared with samples treated with chlorine. A similar result occurred in the potential for trihalomethane formation for 24 hours. In relation to the potencial formation of seven days, both springs were shown to be capable of forming compounds precursors of trihalomethanes. Concentrations of trihalomethanes above the limit allowed by the Ordinance of Ministry of Health number 518 were only detected in samples of treated water from the Sahy River

The SuperCritical Water-cooled nuclear Reactor (SCWR) is one of six Generation-IV nuclear-reactor concepts currently being designed. It will operate at pressures of 25 MPa and temperatures up to 625°C. These operating conditions make a SuperCritical Water (SCW) Nuclear Power Plant (NPP) suitable to support thermochemical-based hydrogen production via co-generation. The Copper-Chlorine (Cu‒Cl) cycle is a prospective thermochemical cycle with a maximum temperature requirement of ~530°C and could be linked to an SCW NPP through a piping network. An intermediate Heat eXchanger (HX) is considered as a medium for heat transfer with operating fluids selected to be SCW and SuperHeated Steam (SHS). Thermalhydraulic calculations based on an iterative energy balance procedure are performed for counter-flow double-pipe design concept HXs integrated at several locations on an SCW NPP coolant loop. Using various test cases, design and operating parameters are recommended for detailed future research. In addition, predicted effects of heat transfer enhancement on HX parameters are evaluated considering theoretical improvements from helically-corrugated HX piping. The effects of operating fluid pressure drop are briefly discussed for applicability in future studies. / UOIT

Global simulations of atmospheric methyl chloride (CH3Cl) are conducted using the GEOS-Chem model in order to understand better its sources and sinks. Though CH3Cl is one of the most abundant organic chlorine species in the stratosphere, not much is known about its sources and the budget remains unbalanced. In addition to the known sources (1.5 Tg yr-1) from ocean, biomass burning, incineration/industry, salt marshes, and wetlands, a hypothetical aseasonal biogenic source of 2.9 Tg yr-1 is added in order to match needed emissions. Observations from 7 surface sites and 8 aircraft field experiments are used to evaluate the model simulations. The model results with a priori emissions and sinks reproduce CH3Cl observations at northern mid and high latitudes reasonably well. However, the seasonal variation of CH3Cl at southern mid and high latitudes is severely overestimated. Simulated vertical profiles show disagreements in the vicinities of major sources, principally reflecting the uncertainties in the estimated distributions of our added pseudo-biogenic and the biomass burning sources. Inverse modeling is applied to obtain optimal source distributions of CH3Cl on the basis of surface and aircraft observations and model results. We resolve the seasonal dependence of the biogenic and biomass burning sources for each hemisphere. The aircraft in situ measurements are found to provide better constraints on the emission sources than surface measurements. The a posteriori emissions result in better agreement with the observations particularly at southern high latitudes. The a posteriori biogenic and biomass burning source decrease by 13 and 11% to 2500 and 545 Gg yr-1, respectively, while the a posteriori net ocean source increases by about a factor of 2 to 761 Gg yr-1. The decrease in biomass burning emissions is largely due to the reduction in the emissions in seasons other than spring in the northern hemisphere. The inversion results indicate that the biogenic source has a clear winter minimum in both hemispheres, likely reflecting the decrease of biogenic activity during that season.

The soil pile system (SPS) is a wastewater infiltration system used for secondary and tertiary treatment of wastewater. The purpose of this study is to perform a feasibility study to assess the applicability of SPS for treatment and safe disposal of domestic wastewaters, using a simplistic steady-state flow analytical modeling and a numerical transient unsaturated flow and transport modeling approaches. It is also aimed to develop guidelines for the design and operation of field scale SPS using the results of modeling studies. The analytical modeling approach (AMA) was used to assess total coliform and chlorine attenuation efficiency in a SPS with clay loam soil. Analytical modeling results showed that SPS can treat wastewater in terms of total coliform and chlorine. Thus, in the light of findings of analytical modeling study, a pilot scale field study was conducted for the identifying the design and operational characteristics of a field scale system. Numerical modeling approach was used to evaluate the impact on contaminant removal of transient nature of wastewater infiltration and redistribution through clay loam soil pile. The results of numerical and analytical models were compared to assess the effect of flow regime on contaminant removal efficiencies. Results show that there is no significant difference between removal efficiencies achieved by numerical and analytical models. Whereupon, analytical model was used to assess behavior of SPS with different soil types, namely silt loam, loam, and sandy loam soils. Model results indicated that SPS can be effective reducing chlorine and total coliform concentrations of wastewater below discharge standards. Results also indicated that SPS is highly sensitive to soil thickness, infiltration rate, soil bulk density and most importantly decay rate coefficients and the performance of SPS is dependent on the design, construction, operation characteristics and soil-environmental conditions of the system.

Disinfection of the municipal water systems is mostly achieved by means of chlorine addition at water treatment plants known as sources. Thus, there should be an adequate chlorine concentration at the source for an effective disinfection throughout the system by considering upper and lower limits of disinfectant. However, since the disinfectants are reactive and decays through the system, chlorine added at the source may not be enough to maintain desired disinfectant residuals which may lead to water quality problems in the water distribution system. Moreover, the disinfectants such as chlorine has also an effect to be carcinogen due to formation of disinfectant by-products. Thus, the system should balance the amount of disinfectant supplied while minimizing the health risk. In such a case, it is recommended that one or more booster disinfection stations can be located throughout the system. Such a method can provide more uniform distribution of the chlorine concentration while reducing the amount of the disinfectant used. In this thesis, optimum scheduling, and injection rates of the booster disinfection stations have been searched. The objective is to minimize the injected mass dosage rate subjected to the provision of adequate and more uniform residual concentration in the network. Determination of variable network hydraulics and chlorine concentrations is held out by EPANET network simulation sofware. A C++ code was developed to interface with EPANET by means of the EPANET Programmer&#039 / s Toolkit for linear optimization of the disinfectant mass dosage rate applied to the network.

Free radicals play a critical role in the formation of tropospheric air pollution, but current condensed chemical mechanisms used in gridded photochemical models under-predict total radical concentrations. This dissertation evaluates three hypotheses regarding radical sources and sinks using environmental chamber data and ambient data from southeast Texas. The first hypothesis, that aromatics chemistry is under-represented as a radical source in condensed chemical mechanisms, was evaluated mainly by using environmental chamber simulations and in part by using ambient simulations. Results indicate that improved characterization of aromatics chemistry in condensed chemical mechanisms will lead to more rapid and extensive free radical formation. The second hypothesis, that alkene reactions are under-represented as a radical source in condensed chemical mechanisms, was also evaluated using chamber data and TexAQS-2000 data. Results indicate that the methods used in mechanism condensation lead to lower estimates of free radical production than detailed, compound specific models. The third hypothesis, chlorine emissions and chemistry as a radical source, was also evaluated in a series of sensitivity analyses with various levels of molecular chlorine emissions. Results imply that incorporating chlorine chemistry in condensed chemical mechanisms is expected to lead to more accurate modeling of OH, HO₂ and O₃, particularly for the southeast Texas region where relatively large chlorine emissions occur from various anthropogenic sources of molecular chlorine. The relative magnitudes of these radical sources (aromatics, alkenes, and molecular chlorine) in southeast Texas were also compared using box modeling with TexAQS-2000 data. Results indicate that the relative importance of these three types of radical sources depends on the strengths of their corresponding emissions. / text

Nearly 250,000 sites with past and present potentially polluting activities need urgent remediation within Europe. Major pollutants include organochlorines (OCls), e.g. chlorinated ethenes (CEs) and hexachlorocyclohexanes (HCHs), mainly used as industrial solvents and pesticides, respectively. Due to improper handling and disposal, OCls contaminants are present in the soil or groundwater surrounding sites, where they have been produced or used. CEs and HCHs can undergo degradation by microorganisms indigenous to the soil or groundwater. Therefore natural attenuation (NA), relying on the in situ biodegradation of pollutants, is considered as a cost effective remediation strategy, yet it requires accurate monitoring methods. Compound specific isotope analysis (CSIA) is a powerful tool to provide information on the extent of degradation and, when combining two isotope systems (2D-CSIA), such as carbon (δ13C) and chlorine (δ37Cl), on reaction mechanisms. The diagnostic reaction-specific isotope enrichment factors (εC and εCl) were determined in laboratory experiments for the anaerobic degradation of PCE, TCE (Paper II) and α-HCH (Paper III) by mixed bacterial cultures enriched from CEs and HCHs contaminated sites, respectively. The related mechanism-specific εCl/εC ratios were calculated as 0.35 ± 0.11 (PCE), 0.37 ± 0.11 (TCE) and 0.52 ± 0.23 (α-HCH). These values are smaller than previously reported values for pure cultures. This is explained by the microbial community composition changes observed during degradation of PCE and α-HCH, which also reflect the variability of the microbial community at the field level. Furthermore, εCl/εC ratio might be bacteria specific. These values allowed the estimation of the extent of contaminant degradation at the respective study sites (Paper III and IV). Application of both isotope systems (δ13C and δ37Cl) led to comparable estimates. However the choice of representative ε values is crucial for an accurate assessment. These studies show that CSIA is useful to quantify in situ degradation of OCls contaminants and identify reaction pathways, by combining δ13C and δ37Cl. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 4: Manuscript.</p>

Soil contamination with petroleum hydrocarbons is a common problem. Toxic compounds such as BTEXs are present in gasoline derivatives. They can move through the soil and contaminate the groundwater, especially if methanol is present. This problem is critical in permeable soil. Although leaching of BTEX compounds from soil to the water is almost temperature dependent, movement of methanol through the soil is not. Methanol can move through the porous soil and reach the groundwater in a short time. It can also dissolve and carry BTEX compounds through the porous soil. Therefore, fast cleanup of the permeable soil which is contaminated with BTEX and methanol is crucial. Chlorine dioxide is an oxidizer, which is easy to use and safe to transport; and may be considered as a treatment technique for soil cleanup. Keywords: Groundwater, soil contamination, BTEX compounds, methanol, chlorine dioxide, soil cleanup