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Development of a lean-premixed, liquid-fueled combustor is in progress to achieve ultra-low NOx emissions at typical gas turbine operating conditions. A filming fuel injector design was tested on a bench scale can combustor to evaluate critical design and operating parameters for low-emissions performance. Testing was completed using No. 2 diesel. Key design variables tested include premixing length, swirler angle, injector centerbody diameter, and reduced liner cooling. NOx emissions below 12 ppmv at 9 bar pressure were measured. Corresponding CO levels were 50 ppmv. An optimized injector design was fabricated for testing in a three injector sector of an annular combustor. Operating parameters and test results are discussed in the paper.

COWELL, L. L., W. G. SQUIRES, and P. B. RAVEN. Benefits of aerobic exercise for the paraplegic: a brief review. Med. Sci. Sports Exerc., Vol. 18, No. 5, pp. 501–508, 1986. The importance of exercise for the general population is emphasized widely; therefore, it must be even more important for paraplegics who are already threatened with poor health due to the sedentary nature of their lifestyle. The effects of functional degeneration are vast and greatly reduce the overall health of paraplegics, particularly within the musculoskeletal and cardiovascular systems, thereby increasing their risk for cardiovascular disease. Recent investigations suggest that this process may be reversible through exercise training and that paraplegics respond to exercise training in essentially the same manner as the non-handicapped individual. In addition, exercise training has been reported to decrease the resorptive process of the skeleton by decreasing bone and collagen catabolism and possibly aiding in new bone formation. This review attempts to summarize the available literature on the effects of exercise on the paraplegic and will hopefully provide some direction not only for further research but also recommendations for practioners working in the field.

Diversity in the antigen-binding receptors of the immune system has long been a primary interest of biologists. Recently it has been suggested that polymorphism in regulatory (noncoding) gene segments is of substantial importance as well. Here, we survey the level of variation in MHC class II gene promoters in man and mouse using extensive collections of published sequences together with unpublished sequences recently deposited by us in the EMBL gene bank using the Shannon entropy to quantify diversity. For comparison, we also apply our analysis to distantly related MHC class II promoters, as well as to class I promoters and to class II coding regions. We observe a high level of intraspecies variability, which in mouse but not in man is localized to a significant extent near the binding sites of transcription factors-sites that are conserved over longer evolutionary distances. This localization may both indicate and enhance heterozygote advantage, as the presence of two functionally different promoters would be expected to confer flexibility in the immune response.

A full-size combustor for a coal-fueled industrial gas turbine engine has been designed and fabricated. The design is based on extensive work completed through one-tenth scale combustion tests. Testing of the combustion hardware will be completed with a high pressure air supply in a combustion test facility before the components are integrated with the gas turbine engine. The combustor is a two-staged, rich-lean design. Fuel and air are introduced in the primary combustion zone where the combustion process is initiated. The primary zone operates in a slagging mode inertially removing coal ash from the gas stream. Four injectors designed for coal water mixture (CWM) atomization are used to introduce the fuel and primary air. In the secondary combustion zone, additional air is injected to complete the combustion process at fuel lean conditions. The secondary zone also serves to reduce the gas temperatures exiting the combustor. Between the primary and secondary zones is a Particulate Rejection Impact Separator (PRIS). In this device much of the coal ash that passes from the primary zone is inertially separated from the gas stream. The two-staged combustor along with the PRIS have been designated as the combustor island. All of the combustor island components are refractory-lined to minimize heat loss. Fabrication of the combustor has been completed. The PRIS is still under construction. The combustor hardware is being installed at the Caterpillar Technical Center for high pressure test evaluation. The design, test installation, and test plan of the full-size combustor island are discussed.

A slagging combustor has been used to evaluate three calcium-based sorbents for sulfur capture efficiency in order to assess their applicability for use in a coal-fueled gas turbine. Testing is completed in a bench-scale combustor with one-tenth the heat input needed for the full-scale gas turbine. The bench-scale rig is a two-stage combustor featuring a fuel-rich primary zone and a fuel-lean secondary zone. The combustor is operated at 6.5 bars with inlet air preheated to 600 K. Gas temperatures of 1840 K are generated in the primary zone and 1280 K in the secondary zone. Sorbents are either fed into the secondary zone or mixed with the coal-water mixture and fed into the primary zone. Dry powdered sorbents are fed into the secondary zone by an auger into one of six secondary air inlet ports. The three sorbents tested in the secondary zone include dolomite, pressure-hydrated dolomitic lime, and hydrated lime. Sorbents have been tested while burning coal-water mixtures with coal sulfur loadings of 0.56 to 3.13 weight percent sulfur. Sorbents are injected into the secondary zone at varying flow rates such that the calcium/sulfur ratio varies from 0.5 to 10.0. Hydrated lime exhibits the highest sulfur dioxide reductions in the exhaust of 90 percent. Pressure-hydrated dolomitic lime and dolomite reduce SO2 concentrations by 82 and 55 percent, respectively. Coal sulfur loading is found to have a small influence on sorbent sulfur capture efficiency. Pressure-hydrated dolomitic lime ground with the coal during coal-water mixture preparation and injected into the primary zone is found to lower the sulfur dioxide concentration by an insignificant amount.

Farmers in Saskatchewan have recently begun intercropping pea with nonlegumes in order to reduce lodging of the pea crop and thus improve harvesting operations. The response of pea and lentil to intercropping and N application was determined at five locations throughout Saskatchewan in 1987. At each site one of the following combinations was tested: lentil and flax, pea and rape, pea and yellow mustard or pea and oats. All treatments received 10, 30 or 50 kg N ha−1as urea. Nitrogen-15 microplots were included to measure N2-fixation and percent fertilizer use efficiency (% FUE). Intercropping reduced lodging and improved harvesting conditions of pea and lentil. An increase in the land equivalent ratio (LER) due to intercropping was observed at two sites where growing conditions were poorer than at the other three sites. At the other sites intercropping systems had a similar or intermediate % FUE to that of the monocropped legume and non-legume. Percent N derived from N2-fixation (% Ndfa) ranged from 4.6 to 87.6, depending on site, level of N application and cropping system. Intercropped legumes had a significantly higher % Ndfa than monocropped legumes at two sites. Nitrogen fertilization reduced the % Ndfa of monocropped legumes at two sites but never affected the % Ndfa of intercropped legumes. Total N2fixed was almost always less in intercropped than in monocropped systems, although only significantly at two sites. No significant lower values for atom % 15N of intercropped non-legumes as compared with monocropped non-legumes were observed, indicating that transfer of N from the legume to the non-legume was minimal. Key words: Intercropping, monocropping, flax, lentil, rape, pea, yellow mustard, oat