Ion exchange equilibria between (Mn,Co)O solid solution and (Mn,Co)Cr2O4 and (Mn,Co)Al2O4 spinel solid solutions at 1100oC

The compositions of the (Mn,Co)O solid solution with rock salt structure in equilibrium with (Mn,Co)Cr2O4 and (Mn,Co)Al2O4 spinel solid solutions have been determined by X-ray diffraction measurements at 1100° C and an oxygen partial pressure of 10–10 atm. The ion exchange equilibria are quantitatively analysed, using values for activities in the (Mn,Co)O solid solution available in the literature, in order to obtain activities in the spinel solid solutions. The MnAl2O4-CoAl2O4 solid solution exhibits negative deviations from Raoult's law, consistent with the estimated cation disorder in the solid solution, while the MnCr2O4-CoCr2O4 solid solution shows slightly positive deviations. The difference in the Gibbs free energy of formation of the two pure chromites and aluminates derived from the results of this study are in good agreement with recent results obtained from solid oxide galvanic cells and gas-equilibrium techniques.

Thermodynamics of oxide sulfate melts: The system PbO PbSO4

Activities in the PbO-PbSO4 melts at 1253 K have been measured by emf and gas-equilibration techniques. The activity of PbO was directly obtained from the emf of the solid oxide cell, Pt, Ni-NiO/CaO-ZrO2/Auo.92PbO.08, PbOx-PbSO4(1-x), Ir, Pt for 1.0 >XPbO > 0.6. The melt and the alloy were contained in closed zirconia crucibles. Since the partial pressure of SO2 gas in equilibrium with the melt and alloy was appreciable (>0.08 atm) atXPbO < 0.6, activities at lower PbO concentrations were derived from measurements of the weight gain of pure PbO under controlled gas streans of Ar + SO2 + O2. The partial and integral free energies of mixing at 1253 K were calculated and found to fit a subregular model: ΔGEPbO =X2PbSO4 {-42,450 + 20,000X2PbSO4} J mol-1 ΔGEPbO =X2pbSO {-12,450 - 20,000XPbS} J mol-1 ΔGEpbSOXPbSO4 {-32,450XPbS - 22,450XPbSO4 } J mol-1. The standard free energy of formation of liquid PbSO4 from pure liquid PbO and gaseous SO3 at 1 atm at 1253 K was evaluated as -88.02 (±0.72) kJ mol-1.

Cr2+:ZnSe中红外激光器

Cr2+掺杂II-VI族化合物在中红外波段的输出，在气体检测、遥感、通信、眼科医学、神经外科等领域有着重要的应用前景。目前已经获得了最大1.7 W的连续输出功率，18.5 W的平均脉冲功率，1100 nm的调谐范围和最窄4 ps的脉宽。对Cr2+:ZnSe连续、脉冲、随机纳米激光器以及其它的Cr2+掺杂II-VI族化合物激光器的最新的国内外研究进展进行了综述。

Identificação de danos estruturais a partir do modelo de superfície de resposta

A identificação de danos estruturais é uma questão de fundamental importância na engenharia, visto que uma estrutura está sujeita a processos de deterioração e a ocorrência de danos durante a sua vida útil. A presença de danos compromete o desempenho e a integridade estrutural, podendo colocar vidas humanas em risco e resultam em perdas econômicas consideráveis. Técnicas de identificação de danos estruturais e monitoramento de estruturas fundamentadas no ajuste de um Modelo de Elementos Finitos (MEF) são constantes na literatura especializada. No entanto, a obtenção de um problema geralmente mal posto e o elevado custo computacional, inerente a essas técnicas, limitam ou até mesmo inviabilizam a sua aplicabilidade em estruturas que demandam um modelo de ordem elevada. Para contornar essas dificuldades, na formulação do problema de identificação de danos, pode-se utilizar o Modelo de Superfície de Reposta (MSR) em substituição a um MEF da estrutura. No presente trabalho, a identificação de danos estruturais considera o ajuste de um MSR da estrutura, objetivando-se a minimização de uma função de erro definida a partir das frequências naturais experimentais e das correspondentes frequências previstas pelo MSR. Estuda-se o problema de identificação de danos estruturais em uma viga de Euler-Bernoulli simplesmente apoiada, considerando as frequências naturais na formulação do problema inverso. O comportamento de uma viga de Euler-Bernoulli simplesmente apoiada na presença de danos é analisado, com intuito de se verificar as regiões onde a identificação dos mesmos pode apresentar maior dificuldade. No processo de identificação de danos, do presente trabalho, são avaliados os tipos de superfícies de resposta, após uma escolha apropriada do tipo de superfície de resposta a ser utilizado, determina-se a superfície de resposta considerando os dados experimentais selecionados a partir do projeto ótimo de experimentos. A utilização do método Evolução Diferencial (ED) no problema inverso de identificação de danos é considerado inerente aos resultados numéricos obtidos, a estratégia adotada mostrou-se capaz de localizar e quantificar os danos com elevada acurácia, mostrando a potencialidade do modelo de identificação de danos proposto.

Use of simple fat analysis for evaluating quality changes in intermediate moisture fish stored at tropical temperature

Changes in the quality of intermediate moisture (IM) fish during storage at 38°C were monitored by assessing the moisture content, pH, acid value, peroxide value and thiobarbituric acid (TBA) value periodically. Results adequately portrayed the hydrolysis and peroxidation of fats and the concomitant protein degradation and crosslinking reactions that have been shown by more sophisticated methods to occur in intermediate moisture fish. Since these changes markedly affect the organoleptic quality, acceptability/shelf-life and nutritive value of IM flesh-foods their predictability by simple fat analytical techniques is of practical value where/when the more sophisticated monitoring techniques are not feasible.

~7Be示踪坡耕地次降雨细沟与细沟间侵蚀

对于坡面细沟与细沟间侵蚀过程的了解是建立侵蚀预报模型的基础,但传统方法难以对其进行深入研究。利用7Be示踪技术并结合人工模拟降雨,考虑坡脚沉积作用,研究了25°坡耕地径流小区次降雨过程中细沟与细沟间侵蚀动态。结果表明:根据流出径流小区泥沙7Be含量变化计算坡面明显细沟出现时间,由于坡脚沉积作用使得A、B两试验小区这一时间比实际细沟出现分别延迟了45min和11min;根据坡面-侵蚀泥沙中7Be总量守恒和泥沙质量平衡原理,坡面细沟间侵蚀及细沟侵蚀在坡面总侵蚀、坡脚沉积区泥沙及流出径流小区泥沙中的比例被定量区分开;总体上,细沟间侵蚀量在径流泥沙中的比例逐渐减少,而细沟侵蚀量逐渐增加。两试验小区中7Be示踪计算坡面细沟侵蚀量和坡脚沉积量与实测值相比相对误差均较小,因此7Be示踪技术可以对土壤侵蚀进行较为准确地定量研究。

Modelling air quality in street canyons: a review

High pollution levels have been often observed in urban street canyons due to the increased traffic emissions and reduced natural ventilation. Microscale dispersion models with different levels of complexity may be used to assess urban air qualityand support decision-making for pollution control strategies and traffic planning. Mathematical models calculate pollutant concentrations by solving either analytically a simplified set of parametric equations or numerically a set of differential equations that describe in detail wind flow and pollutant dispersion. Street canyon models, which might also include simplified photochemistry and particle deposition–resuspension algorithms, are often nested within larger-scale urban dispersion codes. Reduced-scale physical models in wind tunnels may also be used for investigating atmospheric processes within urban canyons and validating mathematical models. A range of monitoring techniques is used to measure pollutant concentrations in urban streets. Point measurement methods (continuous monitoring, passive and active pre-concentration sampling, grab sampling) are available for gaseous pollutants. A number of sampling techniques (mainlybased on filtration and impaction) can be used to obtain mass concentration, size distribution and chemical composition of particles. A combination of different sampling/monitoring techniques is often adopted in experimental studies. Relativelysimple mathematical models have usually been used in association with field measurements to obtain and interpret time series of pollutant concentrations at a limited number of receptor locations in street canyons. On the other hand, advanced numerical codes have often been applied in combination with wind tunnel and/or field data to simulate small-scale dispersion within the urban canopy.

Determination of higher heating value of petro-diesels using mid-infrared spectroscopy and chemometry

Higher heating value (HHV) is probably the most important property of the fuels. Bomb calorimeter and derived empirical formulae are often used for accurate determination of HHV of fuels. A useful empirical equation was derived to estimate HHV of petro-diesels from their C and H contents: HHV (in MJ/kg) = 0.3482(C) + 1.1887(H), r (2) = 0.9956. The derived correlation was validated against the most common formulae in the literature, Boie and Channiwala-Parikh correlations. Accordingly, accurate determination of C and H contents is essential for estimation of HHV and avoids using a bomb calorimeter. However, accurate estimation of C and H contents requires using expensive and laborious gas chromatographic techniques. In this work, chemometry offered a simple method for HHV determination of petro-diesels without using bomb calorimeter or even gas chromatography. PLS-1 calibration was used instead of gas chromatography to find C and H contents from the non-selective mid-infrared (MIR) spectra of petro-diesels, HHV was then estimated from the earlier empirical equation. The proposed method predicts HHV of petro-diesels with high accuracy and precision, with modest analysis costs. The present method may be extended to other fuels.

Detection of Protein-Protein Interactions Using Protein-Fragment Complementation Assays (PCA)

Protein-protein interactions play a central role in many cellular processes. Their characterisation is necessary in order to analyse these processes and for the functional identification of unknown proteins. Existing detection methods such as the yeast two-hybrid (Y2H) and tandem affinity purification (TAP) method provide a means to answer rapidly questions regarding protein-protein interactions, but have limitations which restrict their use to certain interaction networks; furthermore they provide little information regarding interaction localisation at the subcellular level. The development of protein-fragment complementation assays (PCA) employing a fluorescent reporter such as a member of the green fluorescent protein (GFP) family has led to a new method of interaction detection termed Bimolecular Fluorescent Complementation (BiFC). These assays have become important tools for understanding protein interactions and the development of whole genome interaction maps. BiFC assays have the advantages of very low background signal coupled with rapid detection of protein-protein interactions in vivo while also providing information regarding interaction compartmentalisation. Modified forms of the assay such as the use of combinations of spectral variants of GFP have allowed simultaneous visualisation of multiple competing interactions in vivo. Advantages and disadvantages of the method are discussed in the context of other fluorescence-based interaction monitoring techniques.

Contemporary environmental issues of landfill leachate: assessment & remedies

Landfills are the primary option for waste disposal all over the world. Most of the landfill sites across the world are old and are not engineered to prevent contamination of the underlying soil and groundwater by the toxic leachate. The pollutants from landfill leachate have accumulative and detrimental effect on the ecology and food chains leading to carcinogenic effects, acute toxicity and genotoxicity among human beings. Management of this highly toxic leachate presents a challenging problem to the regulatory authorities who have set specific regulations regarding maximum limits of contaminants in treated leachate prior to disposal into the environment to ensure minimal environmental impact. There are different stages of leachate management such as monitoring of its formation and flow into the environment, identification of hazards associated with it and its treatment prior to disposal into the environment. This review focuses on: (i) leachate composition, (ii) Plume migration, (iii) Contaminant fate, (iv) Leachate plume monitoring techniques, (v) Risk assessment techniques, Hazard rating methods, mathematical modeling, and (vi) Recent innovations in leachate treatment technologies. However, due to seasonal fluctuations in leachate composition, flow rate and leachate volume, the management approaches cannot be stereotyped. Every scenario is unique and the strategy will vary accordingly. This paper lays out the choices for making an educated guess leading to the best management option.

HD Laser scanning for the evaluation of salt decay laboratory simulations of building limestone

Laboratory salt decay simulations are a well established method to assess the relative durability of stone. There is still, however, very much scope to implement improved monitoring techniques to investigate the changes experienced by the materials during these experiments. Non-destructive techniques have acquired over recent decades a preferential status for monitoring change samples during salt decay tests, as they allow cumulative tests on each sample. The development of HD laser scanning permits detailed mapping of surface changes and, therefore, constitutes an effective technique to monitor non-destructively surface changes in tested samples as an alternative to other monitoring techniques such as traditional weight loss strategies that do not permit any degree of spatial differentiation that can be related, for example, to underlying stone properties.

Quantitative multiparameter assays to measure the effect of adjuvants on human antigen-specific CD8 T-cell responses.

Large numbers and functionally competent T cells are required to protect from diseases for which antibody-based vaccines have consistently failed (1), which is the case for many chronic viral infections and solid tumors. Therefore, therapeutic vaccines aim at the induction of strong antigen-specific T-cell responses. Novel adjuvants have considerably improved the capacity of synthetic vaccines to activate T cells, but more research is necessary to identify optimal compositions of potent vaccine formulations. Consequently, there is a great need to develop accurate methods for the efficient identification of antigen-specific T cells and the assessment of their functional characteristics directly ex vivo. In this regard, hundreds of clinical vaccination trials have been implemented during the last 15 years, and monitoring techniques become more and more standardized.

‘Biochemical Responses to Heavy Metals in Oreochromis mossambicus with special reference to Metal Detoxifying Mechanism

The present work is focused on the organelle and biochemical responses to heavy metal exposure in the fish Oreochromis mossambicus giving particular importance to the metal detoxifying machinery of the organism. The thesis is an outcome of the effort aimed at developing practicable monitoring techniques to deliver guidelines for biological effect monitoring and the need for specific biochemical methods to detect biological effects of heavy metals that can be interpreted in terms of the health status of the individual organism and eventually alterations in vital processes as growth and reproduction. The efficiency of the metal detoxifying metallothioneins which is an attractive tool for biological monitoring, their role as scavengers of trace metal ions and thus in relieving the biological machinery from their toxicity effects are important themes of this study. Efforts have also been made to test the reliability of the spill over hypothesis of the action of metallothioneins (Winge et a1.,1973) and their use as a biological barometer of heavy metal stress.

Proporción de pacientes que presentan hipotermia peri operatoria durante un reemplazo articular de cadera, rodilla u hombro

Introducción: La hipotermia perioperatoria se ha documentado como factor de riesgo para el aumento de la morbimortalidad de los pacientes aumentando morbilidad miocárdica, riesgo de infección, pérdidas sanguíneas y tiempo de hospitalización. La aplicación de anestésicos toma relevancia ya que causa la pérdida de control central de la temperatura. Nuestro objetivo con este estudio fue describir la proporción de casos de hipotermia en la población sometida a un reemplazo articular durante un periodo de cuatro meses. Materiales y métodos: Se realizó un estudio de cohorte prospectivo. La población a estudio fueron los pacientes que fueron sometidos a un reemplazo total de cadera, rodilla u hombro. Se registró la temperatura central en el momento previo a la inducción anestésica, 30, 60 y 90 minutos después, al finalizar el procedimiento y al ingresar a recuperación. Se reportó el porcentaje de pacientes con hipotermia en cada tiempo. Resultados: Se analizaron en total 88 pacientes, el 55,7% fue llevado a cirugía de cadera, 39,7% de rodilla y 4,5% de hombro. El tipo de anestesia más utilizado fue general y la duración promedio de anestesia fue 164 minutos. La medición de la temperatura central se realizó en nasofaringe, esófago o tímpano. La proporción de pacientes que presentaron hipotermia en la inducción fue 21,6%, a 30 minutos 83%, a 60 minutos 73,9%, a 90 minutos 68,2%, al finalizar 59,1% y en recuperación 58%. Se realizó una prueba Chi cuadrado comparando las proporciones entre la inducción y los cinco periodos posteriores, se encontró que la proporción de pacientes con hipotermia en los cinco tiempos posteriores tuvo una diferencia estadísticamente significativa (p=0,00) comparada con la proporción de pacientes con hipotermia durante la inducción. Conclusión: En los pacientes sometidos a un reemplazo articular la hipotermia fue una condición prevalente posterior a la aplicación de los anestésicos sistémicos. Los dispositivos de calentamiento intraoperatorio usados actualmente son insuficientes para evitar la hipotermia, lo que indica concordancia con la literatura en cuanto a las recomendaciones de calentamiento perioperatorio, con énfasis en el precalentamiento, para prevenir la caída significativa de la temperatura y la morbimortalidad asociada.

Principles and calibration of solid phase microextraction fibre (passive sampler) for measurements of airflow and air infiltration in dwellings

Tracer gas techniques have been the most appropriate experimental method of determining airflows and ventilation rates in houses. However, current trends to reduce greenhouse gas effects have prompted the need for alternative techniques, such as passive sampling. In this research passive sampling techniques have been used to demonstrate the potential to fulfil these requirements by using solutions of volatile organic compounds (VOCs) and solid phase microextraction (SPME) fibres. These passive sampling techniques have been calibrated against tracer gas decay techniques and measurements from a standard orifice plate. Two constant sources of volatile organic compounds were diffused into two sections of a humidity chamber and sampled using SPME fibres. From a total of four SPME fibres (two in each section), reproducible results were obtained. Emission rates and air movement from one section to the other were predicted using developed algorithms. Comparison of the SPME fibre technique with that of the tracer gas technique and measurements from an orifice plate showed similar results with good precision and accuracy. With these fibres, infiltration rates can be measured over grab samples in a time weighted averaged period lasting from 10 minutes up to several days. Key words: passive samplers, solid phase microextraction fibre, tracer gas techniques, airflow, air infiltration, houses.