1,057 research outputs found

    Replacing Conventional PFAS Water Treatment by GAC with Plasma Treatment to Improve Sustainability

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    Per and poly-fluoroalkylated substances (PFAS) are carcinogenic compounds which make their way into water systems and are difficult to remove. Currently, PFAS is removed from drinking water at an industrial scale using granular activated carbon (GAC), a solid particulate which removes PFAS from water through adsorption. However, in recent years, a new method utilizing a plasma reactor to mineralize the PFAS has been designed and tested at small scales. This project aims to increase the scale of existing plasma reactor designs to treat the same volumes of water that traditional GAC plants are capable of treating. A specific well in New Castle County, Delaware was identified as the treatment site, and both processes were designed to treat 2.33 million gallons of water per day by reducing the PFAS concentration from 4,500 parts per trillion to the US EPA health advisory level of 70 parts per trillion. The GAC process was estimated to have a capital cost of 6.73millionandanoperationalcostof6.73 million and an operational cost of 6.32 million each year. The plasma process was estimated to have a capital cost of 14.8millionandanoperationalcostof14.8 million and an operational cost of 5.93 million each year. Based on a number of economic and environmental factors, this project found that the plasma system was a more effective and sustainable method for achieving the desired reduction in PFAS concentration

    La resiliencia en la sostenibilidad empresarial de las medianas empresas industriales manufactureras de Guayas-Ecuador

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    Determina el grado de incidencia del liderazgo, las redes organizacionales y la orientación al cambio como factores de resiliencia en la sostenibilidad empresarial de las medianas empresas industriales manufactureras de la provincia del Guayas en Ecuador. Es una investigación ex post facto, cuantitativa y aplicada. Utiliza una muestra de 163 medianas empresas. Emplea un cuestionario de entrevistas y un cuadro de check list para la variable resiliencia, y un cuestionario tipo Likert para la variable sostenibilidad. Encuentra que la resiliencia incide de manera significativa en la sostenibilidad empresarial de las medianas empresas industriales manufactureras de Guayas.Tesi

    Generation of Dielectrophoretic Force under Uniform Electric Field

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    Effective dipole moment method has been widely accepted as the de facto technique in predicting the dielectrophoretic force due to the non-uniform electric field. In this method, a finite-particle is modeled as an equivalent point-dipole that would induce a same electric field under the external electric field. This approach is only valid when the particle size is significantly smaller than the characteristic length of interest. This assumption is often violated in a microfluidic device, where the thickness or width of the microchannel can be as small as the particle. It is shown in this numerical study that when the dimensions of the particle were in the same order of magnitude as the characteristic length of the device, dielectrophoretic force can be induced even in a uniform electric field. This force arises due to the disturbance of the particle and the bounding wall.Singapore-MIT Alliance (SMA

    A study of financial sector regulation in Hong Kong : towards a nw insurance regulatory regime

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    published_or_final_versionPolitics and Public AdministrationMasterMaster of Public Administratio

    Is the Chinese Stock Market Really Efficient

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    Groenewold et al (2004a) documented that the Chinese stock market is inefficient. In this paper, we revisit the efficiency problem of the Chinese stock market using time-series model based trading rules. Our paper distinguishes itself from previous studies in several aspects. First, while previous studies concentrate on the viability of linear forecasting techniques, we evaluate the profitability of the forecasts of the self-exciting threshold autoregressive model (SETAR), and compare it with the conventional linear AR and MA trading rules. Second, the finding of market inefficiency in earlier studies mainly rest on the statistical significance of the autocorrelation or regression coefficients. In contrast, this paper directly examines the profitability of various trading rules. Third, our sample covers an extensive period of 1991-2010. Sub-sample analysis shows that positive returns mainly concentrate in the pre-SOE reform period, suggesting that China’s stock market has become more efficient after the reform

    Is the Chinese Stock Market Really Efficient

    Get PDF
    Groenewold et al (2004a) documented that the Chinese stock market is inefficient. In this paper, we revisit the efficiency problem of the Chinese stock market using time-series model based trading rules. Our paper distinguishes itself from previous studies in several aspects. First, while previous studies concentrate on the viability of linear forecasting techniques, we evaluate the profitability of the forecasts of the self-exciting threshold autoregressive model (SETAR), and compare it with the conventional linear AR and MA trading rules. Second, the finding of market inefficiency in earlier studies mainly rest on the statistical significance of the autocorrelation or regression coefficients. In contrast, this paper directly examines the profitability of various trading rules. Third, our sample covers an extensive period of 1991-2010. Sub-sample analysis shows that positive returns mainly concentrate in the pre-SOE reform period, suggesting that China’s stock market has become more efficient after the reform

    Lactobacillus porcinae sp. nov. isolated from traditional Vietnamese nem chua

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    A species diversity study of lactic acid bacteria occurring in traditional Vietnamese nem chua yielded an isolate, LMG 26767T, that could not be assigned to a validly named species. The isolate was initially investigated by 16S rRNA gene sequence analysis, which revealed that it belonged to the genus Lactobacillus, with Lactobacillus manihotivorans and Lactobacillus camelliae as the closest relatives (98.9% and 96.9% gene sequence similarity towards the type strains, respectively). Comparative (GTG)5-PCR genomic fingerprinting confirmed the unique taxonomic status of the novel strain. DNA-DNA hybridization experiments, DNA G+C content determination, sequence analysis of the phenylalanyl-tRNA synthase (pheS) gene, and physiological and biochemical characterization demonstrated that strain LMG 26767T (= CCUG 62266T) represents a novel species, for which the name Lactobacillus porcinae sp. nov. is proposed. Biochemically, Lb. porcinae can be distinguished from Lb. manihotivorans and Lb. camelliae by its carbohydrate fermentation profile, absence of growth at 45°C, and production of D- and L- lactate as end products of glucose metabolism

    Nectin-like proteins mediate axon–Schwann cell interactions along the internode and are essential for myelination

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    Axon–glial interactions are critical for the induction of myelination and the domain organization of myelinated fibers. Although molecular complexes that mediate these interactions in the nodal region are known, their counterparts along the internode are poorly defined. We report that neurons and Schwann cells express distinct sets of nectin-like (Necl) proteins: axons highly express Necl-1 and -2, whereas Schwann cells express Necl-4 and lower amounts of Necl-2. These proteins are strikingly localized to the internode, where Necl-1 and -2 on the axon are directly apposed by Necl-4 on the Schwann cell; all three proteins are also enriched at Schmidt-Lanterman incisures. Binding experiments demonstrate that the Necl proteins preferentially mediate heterophilic rather than homophilic interactions. In particular, Necl-1 on axons binds specifically to Necl-4 on Schwann cells. Knockdown of Necl-4 by short hairpin RNA inhibits Schwann cell differentiation and subsequent myelination in cocultures. These results demonstrate a key role for Necl-4 in initiating peripheral nervous system myelination and implicate the Necl proteins as mediators of axo–glial interactions along the internode

    The metabolic response of P. putida KT2442 producing high levels of polyhydroxyalkanoate under single- and multiple-nutrient-limited growth: Highlights from a multi-level omics approach

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    <p>Abstract</p> <p>Background</p> <p><it>Pseudomonas putida </it>KT2442 is a natural producer of polyhydroxyalkanoates (PHAs), which can substitute petroleum-based non-renewable plastics and form the basis for the production of tailor-made biopolymers. However, despite the substantial body of work on PHA production by <it>P. putida </it>strains, it is not yet clear how the bacterium re-arranges its whole metabolism when it senses the limitation of nitrogen and the excess of fatty acids as carbon source, to result in a large accumulation of PHAs within the cell. In the present study we investigated the metabolic response of KT2442 using a systems biology approach to highlight the differences between single- and multiple-nutrient-limited growth in chemostat cultures.</p> <p>Results</p> <p>We found that 26, 62, and 81% of the cell dry weight consist of PHA under conditions of carbon, dual, and nitrogen limitation, respectively. Under nitrogen limitation a specific PHA production rate of 0.43 (g·(g·h)<sup>-1</sup>) was obtained. The residual biomass was not constant for dual- and strict nitrogen-limiting growth, showing a different feature in comparison to other <it>P. putida </it>strains. Dual limitation resulted in patterns of gene expression, protein level, and metabolite concentrations that substantially differ from those observed under exclusive carbon or nitrogen limitation. The most pronounced differences were found in the energy metabolism, fatty acid metabolism, as well as stress proteins and enzymes belonging to the transport system.</p> <p>Conclusion</p> <p>This is the first study where the interrelationship between nutrient limitations and PHA synthesis has been investigated under well-controlled conditions using a system level approach. The knowledge generated will be of great assistance for the development of bioprocesses and further metabolic engineering work in this versatile organism to both enhance and diversify the industrial production of PHAs.</p

    2-(1H-Pyrazol-3-yl)pyridinium chloride monohydrate

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    The title organic salt, C8H8N3 +·Cl−·H2O, exhibits a rich hydrogen-bonding network involving all constituent species. The water mol­ecules are engaged in strong O—H⋯Cl inter­actions with the chloride anions, two neighboring protonated 2-(1H-pyrazol-3-yl)pyridinium species inter­act via N—H⋯N bonds with two pyrazole rings. Further, a short and highly directional C—H⋯O inter­action is observed connecting the pyridinium ring to the water mol­ecule of crystallization. Weak C—H⋯Cl and N—H⋯Cl inter­actions contribute to the stabilization of the crystal structure
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