Combined chemical (ozone) and biological treatment of polychlorinated biphenyls (PCBs) adsorbed to sediments

Laboratory experiments were conducted to test the feasibility of ozone sparging to oxidize PCBs in sediments, and to determine the organic acid content and biodegradability of the oxidation products. Two PCBs were tested; 2‐,2′‐dichlorobiphenyl (DCB) and 2‐,3‐,4‐,2′‐,3′‐,4′‐hexachlorobiphenyl (HCB). DCB and HCB were allowed to adsorb onto solids in slurries of pure kaolinite and river sediments containing 2% native organic matter (NOM). Ozone was sparged through the slurries while concentrations of PCBs and Cl^?, and chemical oxygen demand (COD) were measured with time. Gas chromatography/mass spectrometry (GC/MS) was used to identify the organic acids produced from the reaction of ozone with DCB and HCB. After sparging, the liquid was placed in bioreactors with inoculum from a domestic wastewater treatment plant and nutrients. Ozone sparging in the kaolinite slurries removed 94% of HCB and 97% of DCB in 30 days. In contrast, 55 days were required to achieve the same PCB removal in river sediment slurries. Ozone doses per g of DCB and HCB in kaolinite were 19 g and 30 g, respectively. Doses were 13–14 times greater in river sediments. Formic and oxalic acids were ozonation products of both PCBs. Specific ozonation products of DCB and HCB were 2‐hydroxybenzoic acid and 2,3,4‐trihydroxybenzoic acid, respectively. The results show that ozone caused ring cleavage of PCBs and stoichiometric replacement of Cl with OH groups. Over 93% of the soluble COD from ozone sparging was biodegraded within 20–26 days in the bioreactors. © 2002 Society of Chemical Industry     

A hybrid MPI–OpenMP scheme for scalable parallel pseudospectral computations for fluid turbulence

A hybrid scheme that utilizes MPI for distributed memory parallelism and OpenMP for shared memory parallelism is presented. The work is motivated by the desire to achieve exceptionally high Reynolds numbers in pseudospectral computations of fluid turbulence on emerging petascale, high core-count, massively parallel processing systems. The hybrid implementation derives from and augments a well-tested scalable MPI-parallelized pseudospectral code. The hybrid paradigm leads to a new picture for the domain decomposition of the pseudospectral grids, which is helpful in understanding, among other things, the 3D transpose of the global data that is necessary for the parallel fast Fourier transforms that are the central component of the numerical discretizations. Details of the hybrid implementation are provided, and performance tests illustrate the utility of the method. It is shown that the hybrid scheme achieves good scalability up to ～20,000 compute cores with a maximum efficiency of 89%, and a mean of 79%. Data are presented that help guide the choice of the optimal number of MPI tasks and OpenMP threads in order to maximize code performance on two different platforms.     

The scholarly influence of Heinz Klein: ideational and social measures of his impact on IS research and IS scholars

Heinz Klein was a fine scholar and mentor whose work and life have inspired us to explore the notion of ‘scholarly influence’ which we cast as ‘ideational’ and ‘social influence’. We adopt a portfolio of measures approach, using the Hirsch family of statistics to assess ideational influence and Social Network Analysis centrality measures for social influence to profile Heinz Klein's contribution to information systems (IS) research. The results show that Heinz was highly influential in both ideational terms (a significant body of citations) and social terms (he is close to the heart of the IS research community). Reflecting on the major research themes and scholarly values espoused by Klein we define a ‘Kleinian view of IS research’, grounded in Habermas’ Theory of Communicative Action, and use that to frame four affirmative propositions to address what we observe to be a distortion and attenuation of the academic discourse on the evaluation of scholarly production. This paper argues that focus should be shifted from the venue of publication of the research to the uptake of the ideas contained in it, thus increasing the openness of the discourse, participation in the discourse, truthfulness, and reduction of the inequities in power distribution within academia.     

A new stereolithography experimental porous flow device

A new method for constructing laboratory-scale porous media with increased pore-level variabilities for two-phase flow experiments is presented here. These devices have been created with stereolithography directly on glass, thus improving the stability of the model created with this precision rapid construction technique. The method of construction and improved parameters are discussed in detail, followed by a brief comparison of two-phase drainage results for air invasion into the water-saturated porous medium. Flow through the model porous medium is shown to substantiate theoretical fractal predictions.     

On the Palladium-On-Charcoal Disproportionate of Rosin

Abstract

Changes in the composition of gum rosin during disproportionate in the presence of 5% palladium-on-charcoal have been determined by gas chromatography. The principal reaction product was dehydro-abietic acid. The exocyclic vinyl group of the pimaric/isopimaric-type resin acids was hydrogenated completely. Only a small amount of dihydroabietic acids was formed. Eight dihydro resin acids were identified. No tetrahydro resin acids were observed.     

通过理解测试价值来降低制造成本

今天在客户打开一个产品包装,而发现产品不能用时,除了产品上印刷的品牌名称外,客户并没有概念是谁制造了这个产品。从市场概念到研发到产品开发、原材料供给、制造、分销、客户、甚至到回头客,这一流程在确定测试的价值中具有至关重要的作用。我们进行测试的目的,是保证我们的产品能够以设计的方式及客户预期的方式工作。在当前的外包环境中,我们进行测试的另一个目的,是确保控制供应链。     

Minimum spouting velocity of dense particles in shallow spouted beds

Quantitative method is used to experimentally measure the minimum spouting velocity in shallow conical spouted bed. And a new minimum spouting correlation for shallow conical spouted beds is developed. It is based on spherical ZrO₂ particles whose density is as high as 5890 kg/m³ while the other U_ms correlations published so far are mainly based on relatively deep conical beds composed of lower density particles with density around or lower than 3000 kg/m³. The new U_ms correlation can predict U_ms of heavy particles well within the range of the experimental matrix. © 2011 Canadian Society for Chemical Engineering     

Flexible corrections of juror judgments: Implications for jury instructions.

The Flexible Correction Model (FCM, D. T. Wegener & R. E. Petty, 1997; D. T. Wegener, R. E. Petty, & M. Dunn, 1998) conceptualizes efforts at bias correction (i.e., attempts to remove influences that are perceived as illegitimate or unwanted) as guided by people's naive theories (perceptions) of the influences at work in that judgment setting. In this article, the authors present this model, discuss the general support for this model outside of courtroom judgment, and discuss a variety of implications of this model for courtroom judgment in general and for the impact of judges' instructions to juries in particular. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of reaction mechanism of coal-metal oxide interactions in chemical-looping combustion

The knowledge of reaction mechanism is very important in designing reactors for chemical-looping combustion (CLC) of coal. Recent CLC studies have considered the more technically difficult problem of reactions between abundant solid fuels (i.e. coal and waste streams) and solid metal oxides. A definitive reaction mechanism has not been reported for CLC reaction of solid fuels. It has often been assumed that the solid/solid reaction is slow and therefore requires that reactions be conducted at temperatures high enough to gasify the solid fuel, or decompose the metal oxide. In contrast, data presented in this paper demonstrates that solid/solid reactions can be completed at much lower temperatures, with rates that are technically useful as long as adequate fuel/metal oxide contact is achieved. Density functional theory (DFT) simulations as well as experimental techniques such as thermo-gravimetric analysis (TGA), flow reactor studies, in situ X-ray photo electron spectroscopy (XPS), in situ X-ray diffraction (XRD) and scanning electron microscopy (SEM) are used to evaluate how the proximal interaction between solid phases proceeds. The data indicate that carbon induces the Cu-O bond breaking process to initiate the combustion of carbon at temperatures significantly lower than the spontaneous decomposition temperature of CuO, and the type of reducing medium in the vicinity of the metal oxide influences the temperature at which the oxygen release from the metal oxide takes place. Surface melting of Cu and wetting of carbon may contribute to the solid-solid contacts necessary for the reaction.