Operating Strategy To Meet SWTR Disinfection Regulations At The Los Angeles Aqueduct Filtration Plant

Preozonation facilities were installed at the Los Angeles Aqueduct Filtration Plant originally to enhance coagulation assistance (microflocculation). The Surface Water Treatment Rule will amend this primary purpose to meeting disinfection standards. Additional ozone generation equipment and a revised ozone system operating strategy will be required to accomplish these changed objectives. The topics discussed in this paper are the considerations surrounding the development of a successful, cost-effective operating strategy. The strategy proposed herein was based on data collected between January and July 1991. On-line process monitoring plans and automated system control logic are described.     

Extraction of plasma triacylglycerols by the mammary gland of the lactating cow

The fatty acid content of triacylglycerols (TG) in arterial and mammary venous blood plasma has been analysed in five cows that were close to peak lactation. The fatty acids in arterial TG were extracted by the mammary gland in amounts 14:0 less than 16:0 less than 18:0 and 18:0 greater than 18:1n - 9 greater than 18:2. The difference of extraction between palmitate and stearate was similar in different TG species. The fatty acid 18:1n - 7, which was largely the trans isomer, was extracted more than 18:1n - 9. Significant amounts of phytanic acid were acylated in plasma TG, but not extracted by the mammary gland.     

Detection of clonal platelet antibodies in immunologically-mediated thrombocytopenias: association with circulating clonal/oligoclonal B cells

Aware that T and B cells in autoimmune thrombocytopenia are abnormal, including the existence of clonal B cell populations, we sought to characterize this clonal phenomenon in various immunological thrombocytopenias using platelet antibody light chain analysis, flow cytometry, Southern blot analysis, and PCR. Using a monoclonal antibody-antigen capture ELISA, we analysed sera from 21 of 26 patients with autoimmune, alloimmune, or drug-induced immunological thrombocytopenia for the light chain phenotypes of their platelet antibodies. Alloantibodies and drug-dependent antibodies from four and 14 patients, respectively, were found that expressed a predominant type of light chain, suggesting that these platelet-reactive antibodies were monoclonal or oligoclonal in nature. 14 of the 26 patients were available for light chain B cell phenotyping studies. Of these 14 patients, thrombocytopenia was due to autoimmunity in two, drug-induced immunity in four, and alloimmunity in eight. We detected clonal populations of B cells in all 14 patients by flow cytometry. Although six of these latter patients possessed platelet antibodies with clonal characteristics, light chain phenotypes of antibodies in five patients were opposite to those of their B cells. Eight of these patients were further examined for immunoglobulin gene rearrangement using Southern and/or polymerase chain reaction analysis. In all eight patients we detected clonal or oligoclonal B cell populations. Only two of these patients had malignancies (chronic lymphocytic leukaemia) that would be expected to have detectable clonal B cells, and thus the mechanism for clonal expansion in the other six patients did not appear to be related to an obvious neoplastic process. Prior to these studies, detection of clonal B cells in thrombocytopenic patients without known malignancies was limited to individuals with autoimmune thrombocytopenia, prompting the speculation that this particular autoimmune disorder arises from B cell dysregulation, rather than from expansion of specific autoantibody producing B cell clones. In contrast, the current studies provide evidence that clonal B cells are common to patients with any form of immunologically-mediated thrombocytopenia. Moreover, the majority of the platelet antibodies (86%) present in these disorders exhibited monoclonal characteristics in that there was an apparent restriction in light chain usage.     

Effect of long-term application of animal slurries to grassland on silage quality assessed in laboratory silos

The effect on silage quality of slurry type (pig or cow), rate of application of slurry (50, 100 or 200 m³ ha^?1 year^?1) and use of a bacterial silage inoculant, was assessed on grass from a long-term slurry experiment ensiled in laboratory silos. There was no significant effect of slurry type or the quality of silage made from grass re growths. However, on the basis of ammonia-N, lactate and volatile fatty acid contents, spring (first cut) grass treated with cow slurry in both years of the study produced significantly poorer fermentation (P < 0.001) than silage from grass treated with pig slurry. The quality of silage made from slurry-treated swards compared favourably with that from swards treated with granular fertiliser. Although increasing the rate of slurry application was shown to reduce fermentation quality in most treatments, this was seen as an effect of increasing the total-N content of the herbage rather than of slurry application per se. From a study, in selected treatments, of the bacterial flora at harvest, it was also observed that slurry application had little impact on either the composition or diversity of herbage enter bacteria at harvest, and therefore probably upon subsequent fermentation. No evidence was found for the occurrence of clostridia on herbage from slurry-treated swards. Use of a bacterial inoculant (Ecosyl; ICI plc) improved fermentation quality significantly (P < 0.001) even where high rates of slurry (200 m³ ha^?1 year^?1) had been applied to swards. The high acetate and butyrate contents typical of laboratory silages untreated with additive were not seen in the inoculated silages.     

Fatigue testing of uPVC pressure pipe

Many uPVC pressure pipe service failures have been due to fatigue crack propagation from a flaw in the internal wall surface of the pipe, often aggravated by the local soil loading conditions. Such failures can be simulated by machining an internal notch (known flaw) into the wall of the pipe before cyclic internal water pressurization.A constant-displacement compressive loading has been found to reduce significantly the fatigue life of uPVC pressure pipe. The frequency and amplitude of the internal cyclic pressure have both been found to affect the fatigue life of uPVC pipe.     

Mass spectra of the picolinyl ester derivatives of some non-methylene-interrupted octadecadienoic acids

The electron-impact mass spectra of the picolinyl ester derivatives of 5,12-, 6,12-, 7,12-, 8,12-, 6,10- and 6,11-octadecadienoic acids were obtained. There are features in each that are diagnostic of the position of the terminal double bond, although doubt could exist, with unknown compounds, about the position of the proximal double bond if authentic spectra were not available for comparison purposes. There appear to be features in the spectra of isomers with two and three methylene groups between double bonds that are of value for characterization purposes.     

Analysis of error growth for explicit difference schemes in conduction–convection problems

A detailed study is made of the error growth associated with explicit difference schemes for a conduction-convection problem. It is shown that the error can become arbitrarily large after a finite number of time steps even though it ultimately decays to zero. Certain ambiguities reported in the literature can thereby be resolved.