Water-cooled probe technique for the study of freeze lining formation

Furnace protection by water-cooled freeze linings becomes increasingly important as the metal producing industry attempts to achieve higher process intensities. Systematic investigations of the growth and the resulting microstructure and compositional profile of freeze linings are necessary to understand the behavior of freeze linings, their relation with the industrial process, and their interaction with the wall cooling system. We have developed a technique based on the submergence of a water-cooled probe into a liquid slag bath. Freeze linings of two industrial nonferrous slags have been produced using this technique and their growth, microstructural, and compositional profiles as a function of submergence time were determined. Thermodynamic equilibrium for the investigated slag systems was calculated and compared with the observed microstructures. The freeze linings form in approximately 15 minutes. Close to the water cooling, the freeze linings are predominantly amorphous in structure. With increasing distance from the water cooling, the proportion of crystalline phases increases and bath material is entrapped in the microstructure. Cellular crystals are observed close to the bath. The freeze linings exhibit an approximate homogeneous composition. The results demonstrate that the technique is a successful tool in obtaining information on the growth, microstructure, and composition of freeze linings in industrial water-cooled furnaces.     

Development and application of an electron spin resonance spectrometry method for the determination of oxygen free radical formation by particulate matter

Exposure to increased levels of ambient particulate matter (PM) are associated with several health effects, including cardiopulmonary diseases. The formation of reactive oxygen species (ROS) is thought to play an important role in the induction of these health effects. To quantify the ROS generating capacityof PM,we developed an improved electron spin resonance (ESR) spectrometry-based method. ROS formation was measured directly on PM-containing filters, thereby avoiding the selective extraction of components and loss of material or reactivity, which is likely to occur during filter extraction. Also, ascorbic acid was added to stimulate ROS formation. This method was applied to PM10 samples originating from different sources. The radical generating capacity of PM10 from both gasoline and diesel engine exhaust was significantly higher as compared to that of PM10 from ambient or indoor air. Furthermore, in urban PM10 and PM2.5, ROS-generating capacity significantly correlated with concentrations of polycyclic aromatic hydrocarbon content and particular transition metals. This indicates thatthis improved ESR method may be a valuable tool for evaluating the relationship between ROS formation by PM and the adverse health effects associated with this type of air pollution.     

Analysis of light noise sources in a recycled Michelson interferometer with Fabry-Perot arms

We present a method by which the effect of laser field variations on the signal output of an interferometric gravitational wave detector is rigorously determined. Using the Laser Interferometer Gravitational Wave Observatory (LIGO) optical configuration of a power recycled Michelson interferometer with Fabry-Perot arm cavities as an example, we calculate the excess noise after the input filter cavity (mode cleaner) and the dependence of the detector strain sensitivity on laser frequency and amplitude noise, radio frequency oscillator noise, and scattered-light phase noise. We find that noise on the radio frequency sidebands generally limits the detector's sensitivity.     

Biharmonic analysis of rectilinear plates by the boundary element method

An improved boundary element formulation (BEM) for two-dimensional non-homogeneous biharmonic analysis of rectilinear plates is presented. A boundary element formulation is developed from a coupled set of Poisson-type boundary integral equations derived from the governing non-homogeneous biharmonic equation. Emphasis is given to the development of exact expressions for the piecewise rectilinear boundary integration of the fundamental solution and its derivatives over several types of isoparametric elements. Incorporation of the explicit form of the integrations into the boundary element formulation improves the computational accuracy of the solution by substantially eliminating the error introduced by numerical quadrature, particularly those errors encountered near singularities. In addition, the single iterative nature of the exact calculations reduces the time necessary to compile the boundary system matrices and also provides a more rapid evaluation of internal point values than do formulations using regular numerical quadrature techniques. The evaluation of the domain integrations associated with biharmonic forms of the non-homogeneous terms of the governing equation are transformed to an equivalent set of boundary integrals. Transformations of this type are introduced to avoid the difficulties of domain integration. The resulting set of boundary integrals describing the domain contribution is generally evaluated numerically; however, some exact expressions for several commonly encountered non-homogeneous terms are used. Several numerical solutions of the deflection of rectilinear plates using the boundary element method (BEM) are presented and compared to existing numerical or exact solutions.     

Processing athabasca tar sands — tailings disposal

Public awareness and concern over the tailings disposal aspects of tar sand development are increasing. This paper describes why the hot water extraction process can lead to an accumulation of tailings sludge. A theory is proposed to predict tailings accumulation rate; predictions are compared with GCOS' operating experience. Using this theory, future projects can be evaluated on their merits without extrapolating GCOS' experience, which may or may not be applicable. Several unsuccessful approaches to reducing sludge accumulation are described to encourage others to seek new approaches.     

Effect of plant residues on the parasitic activity of soilborne pathogens and the saprophytic microflora of the soil. I. Model trials with Rhizoctonia solani Kühn (author's transl)]

1. In glass-house trials the influence of residues of clover, grass, and mixtures (1:1) of them added to natural and partially sterilized loam soil upon the parasitic activity of Rhizoctonia solani and the soil micro-organisms and their activity was analyzed. 2. Burying of plant residues (1%) increased the content of organic substance in soil for 8 weeks and longer. 3. The soil reaction (pH) was not noteworthy affected by application of clover or grass residues. 4. However, the populations of bacteria and actinomycetes were increased, especially by adding clover dried. In natural soil, the maximum of stimulation was reached later than in soil sterilized. Adding of grass and roots of grass enlarged the spectrum of fungi observed in the soil amended. Roots of grass stimulated the cellulose-decomposing organisms remarkably. 5. The activity of dehydrogenase (AD) was influenced in different manner: in natural soil fresh clover, grass, mixtures of them, and clover dried increased, and fresh roots of clover, grass, and mixtures of them diminished AD; in soil sterilized the most variants stimulated this activity. 6. All plants residues increased the cellulolytic activity of soil for a long time, but in sterilized soil this effect reached its maximum earlier than in natural soil amended and did not last so long, too. 7. The possible explanations for the inhibition of parasitic activity of Rhizoctonia solani caused by burying plant residues are discussed.     

Identification of Hymenoxon in Baileya multiradiata and Helenium hoopsii

Monocarboxylic acid derivaties of vitamin B12 were covalently coupled to 1,6-hexanediamine-substituted Sepharose by using a water-soluble carbodiimide resulting in 1.32 micronmoles of B12 coupled per ml of Sepharose. After a source of crude hog intrinsic factor (IF) was passed over the column, a selective linear gradient of guanidine HC1 (0 to 4.0 M) was used to remove IF and 4.0 to 7.5 M to elute NIF (a vitamin B12-binding glycoprotein not active in promoting vitamin B12 absorption). Anti-IF antibodies blocked 99% of the B12 binding by the isolated IF and only 1% of the B12 binding by NIF. Passage over a hydroxyapatite column resulted in IF 99% pure with a specific activity of 29.8 microng of B12 binding per mg of protein. IF so isolated exhibited one homogeneous band on polyacrylamide gel electrophoresis and corrected B12 malabsorption in a patient with pernicious anemia.     

Ultrasensitive proteomics using high-efficiency on-line micro-SPE-nanoLC-nanoESI MS and MS/MS

Ultrasensitive nanoscale proteomics approaches for characterizing proteins from complex proteomic samples of <50 ng of total mass are described. Protein identifications from 0.5 pg of whole proteome extracts were enabled by ultrahigh sensitivity (<75 zmol for individual proteins) achieved using high-efficiency (peak capacities of approximately 10(3)) 15-microm-i.d. capillary liquid chromatography separations (i.e., using nanoLC, approximately 20 nL/min mobile-phase flow rate at the optimal linear velocity of approximately 0.2 cm/s) coupled on-line with a micro-solid-phase sample extraction and a nanoscale electrospray ionization interface to a 11.4-T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer (MS). Proteome measurement coverage improved as sample size was increased from as little as 0.5 pg of sample. It was found that a 2.5-ng sample provided 14% coverage of all annotated open reading frames for the microorganism Deinococcus radiodurans, consistent with previous results for a specific culture condition. The estimated detection dynamic range for detected proteins was 10(5)-10(6). An improved accurate mass and LC elution time two-dimensional data analysis methodology, used to both speed and increase the confidence of peptide/protein identifications, enabled identification of 872 proteins/run from a single 3-h nanoLC/FTICR MS analysis. The low-zeptomole-level sensitivity provides a basis for extending proteomics studies to smaller cell populations and potentially to a single mammalian cell. Application with ion trap MS/MS instrumentation allowed protein identification from 50 pg (total mass) of proteomic samples (i.e., approximately 100 times larger than FTICR MS), corresponding to a sensitivity of approximately 7 amol for individual proteins. Compared with single-stage FTICR measurements, ion trap MS/MS provided a much lower proteome measurement coverage and dynamic range for a given analysis time and sample quantity.