Fuel Consumption of a Carburetor Engine at Various Speeds and Torques

An investigation was conducted to obtain fuel-consumption curves for a single-cylinder engine with a Wright 1820-G and Pratt & Whitney 1340-H cylinder at varying speeds, manifold pressures, and air-fuel ratios. The 1340- H cylinder was tested at speeds from 1,200 to 2,400 r.p.m. and at manifold pressures from 21 to 38 inches of mercury absolute. Less than extensive tests were made of the 1820-G cylinder. The results of the tests showed that the minimum brake fuel consumption was obtained when the engines were operating at high torques and at speeds from 60 to 70 percent of the rated speed. The fuel consumption increased at an increasing rate as the torque was reduced; and, at 45 percent of maximum torque, the fuel consumption was 20 percent higher than at maximum torque when the engines were operating at 70 percent of rated speed. Minimum specific fuel consumption was obtained at the same air-fuel ratio regardless of compression ratio. No improvement in fuel consumption was obtained when mixtures leaner than an air-fuel ratio of 15.5 were used. The leanest mixture ratio on which the engine with the 1340-H cylinder would operate smoothly was 18.5 and the spark advance for maximum power with this mixture ratio was 50 degrees B.T.C. A method is discussed for reducing the amount of testing necessary to obtain curves for minimum brake fuel consumption

Comparative Performance of Engines Using a Carburetor, Manifold Injection, and Cylinder Injection

The comparative performance was determined of engines using three methods of mixing the fuel and the air: the use of a carburetor, manifold injection, and cylinder injection. The tests were made of a single-cylinder engine with a Wright 1820-G air-cooled cylinder. Each method of mixing the fuel and the air was investigated over a range of fuel-air ratios from 0.10 to the limit of stable operation and at engine speeds of 1,500 and 1,900 r.p.m. The comparative performance with a fuel-air ratio of 0.08 was investigated for speeds from 1,300 to 1,900 r.p.m. The results show that the power obtained with each method closely followed the volumetric efficiency; the power was therefore the highest with cylinder injection because this method had less manifold restriction. The values of minimum specific fuel consumption obtained with each method of mixing of fuel and air were the same. For the same engine and cooling conditions, the cylinder temperatures are the same regardless of the method used for mixing the fuel and the air

New treatments for advanced cancer: an approach to prioritization

The allocation of funding for new anticancer treatments within the UK has not kept pace with demand. Clinicians find themselves restricted in the use of licensed drugs which they feel are in the best interests of individual patients. Against this, health authorities have a duty to ensure that scarce resources are used equitably to meet the needs of the local population as a whole. Differential levels of funding for new treatments across the country have led to concerns about rationing by postcode. This paper outlines an approach to the prioritization of new treatment for advanced cancer developed jointly by clinicians and health authorities in South London. The approach involves evidence reviews and consensus meetings. Existing and new treatments are rated on a four-point ‘relative effectiveness scale’, which takes account of the impact of the treatment on quality of life and on survival. The strength of evidence supporting each effectiveness rating is also classified. Health Authorities have used these ratings to determine overall funding levels, while leaving decisions on individual patients to the relevant Trusts. © 2000 Cancer Research Campaig

Performance of NACA Eight-stage Axial-flow Compressor Designed on the Basis of Airfoil Theory

The NACA has conducted an investigation to determine the performance that can be obtained from a multistage axial-flow compressor based on airfoil research. A theory was developed; an eight-stage axial-flow compressor was designed, constructed, and tested. The performance of the compressor was determined for speeds from 5000 to 14,000 r.p.m with varying air flow at each speed. Most of the tests were made with air at room temperature. The performance was determined in accordance with the Committee's recommended procedure for testing superchargers. The expected performance was obtained, showing that a multistage compressor of high efficiency can be designed by the application of airfoil theory

DFM synthesis approach based on product-process interface modelling. Application to the peen forming process.

Engineering design approach are curently CAD-centred design process. Manufacturing information is selected and assessed very late in the design process and above all as a reactive task instead of being proactive to lead the design choices. DFM appraoches are therefore assesment methods that compare several design alternatives and not real design approaches at all. Main added value of this research work concerns the use of a product-process interface model to jointly manage both the product and the manufacturing data in a proactive DFM way. The DFM synthesis approach and the interface model are presented via the description of the DFM software platform

Differential Localization of G Protein βγ Subunits

G protein βγ subunits play essential roles in regulating cellular signaling cascades, yet little is known about their distribution in tissues or their subcellular localization. While previous studies have suggested specific isoforms may exhibit a wide range of distributions throughout the central nervous system, a thorough investigation of the expression patterns of both Gβ and Gγ isoforms within subcellular fractions has not been conducted. To address this, we applied a targeted proteomics approach known as multiple-reaction monitoring to analyze localization patterns of Gβ and Gγ isoforms in pre- and postsynaptic fractions isolated from cortex, cerebellum, hippocampus, and striatum. Particular Gβ and Gγ subunits were found to exhibit distinct regional and subcellular localization patterns throughout the brain. Significant differences in subcellular localization between pre- and postsynaptic fractions were observed within the striatum for most Gβ and Gγ isoforms, while others exhibited completely unique expression patterns in all four brain regions examined. Such differences are a prerequisite for understanding roles of individual subunits in regulating specific signaling pathways throughout the central nervous system

Bound States and Critical Behavior of the Yukawa Potential

We investigate the bound states of the Yukawa potential $V(r)=-\lambda \exp(-\alpha r)/ r$, using different algorithms: solving the Schr\"odinger equation numerically and our Monte Carlo Hamiltonian approach. There is a critical $\alpha=\alpha_C$, above which no bound state exists. We study the relation between $\alpha_C$ and $\lambda$ for various angular momentum quantum number $l$, and find in atomic units, $\alpha_{C}(l)= \lambda [A_{1} \exp(-l/ B_{1})+ A_{2} \exp(-l/ B_{2})]$, with $A_1=1.020(18)$, $B_1=0.443(14)$, $A_2=0.170(17)$, and $B_2=2.490(180)$.Comment: 15 pages, 12 figures, 5 tables. Version to appear in Sciences in China

DFM synthesis approach based on product-process interface modelling. Application to the peen forming process.

International audienceEngineering design approach are curently CAD-centred design process. Manufacturing information is selected and assessed very late in the design process and above all as a reactive task instead of being proactive to lead the design choices. DFM appraoches are therefore assesment methods that compare several design alternatives and not real design approaches at all. Main added value of this research work concerns the use of a product-process interface model to jointly manage both the product and the manufacturing data in a proactive DFM way. The DFM synthesis approach and the interface model are presented via the description of the DFM software platform