Effect of fuel density and heating value on ram-jet airplane range

An analytical investigation of the effects of fuel density and heating value on the cruising range of a ram-jet airplane was made. Results indicate that with present-day knowledge of chemical fuels, neither very high nor very low fuel densities have any advantages for long-range flight. Of the fuels investigated, the borohydrides and metallic boron have the greatest range potential. Aluminum and aluminum hydrocarbon slurries were inferior to pure hydrocarbon fuel and boron-hydrocarbon slurries were superior on a range basis. It was concluded that the practical difficulties associated with the use of liquid hydrogen fuel cannot be justified on a range basis

Turbine Engines for High-Speed Flight

This analysis investigates the application of gas turbine engines at a cruise Mach number of 4

Under the radar? 'Soft' residential densification in England, 2001-2011

Urban compaction policies have been widely adopted in developed countries in pursuit of more sustainable cities. Compactness is achieved through a process of ‘densification’, of developing and using land and buildings more intensively. However, empirical evidence on the processes and outcomes of urban densification is lacking. The paper addresses this lacuna. It considers densification in England, a country that has long experience of applying policies of urban containment and consolidation; and one where new data sources allow the analysis of recent land use change at a level of detail not hitherto possible. In England between 2001 and 2011 the bulk of additional dwellings were accommodated within urban areas, increasing their density. Yet there were wide inter- and intra-regional variations in the pattern of densification: for example, in the contributions of large scale, formal development and of small scale, informal, gradual change – of ‘hard’ and ‘soft’ densification – to the process. The significant differences in local experiences of densification that result raise major issues for policy

Keys to success for prospective agricultural exporters

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

Analysis of gas turbine engines using water and oxygen injection to achieve high Mach numbers and high thrust

An analysis of gas turbine engines using water and oxygen injection to enhance performance by increasing Mach number capability and by increasing thrust is described. The liquids are injected, either separately or together, into the subsonic diffuser ahead of the engine compressor. A turbojet engine and a mixed-flow turbofan engine (MFTF) are examined, and in pursuit of maximum thrust, both engines are fitted with afterburners. The results indicate that water injection alone can extend the performance envelope of both engine types by one and one-half Mach numbers at which point water-air ratios reach 17 or 18 percent and liquid specific impulse is reduced to some 390 to 470 seconds, a level about equal to the impulse of a high energy rocket engine. The envelope can be further extended, but only with increasing sacrifices in liquid specific impulse. Oxygen-airflow ratios as high as 15 percent were investigated for increasing thrust. Using 15 percent oxygen in combination with water injection at high supersonic Mach numbers resulted in thrust augmentation as high as 76 percent without any significant decrease in liquid specific impulse. The stoichiometric afterburner exit temperature increased with increasing oxygen flow, reaching 4822 deg R in the turbojet engine at a Mach number of 3.5. At the transonic Mach number of 0.95 where no water injection is needed, an oxygen-air ratio of 15 percent increased thrust by some 55 percent in both engines, along with a decrease in liquid specific impulse of 62 percent. Afterburner temperature was approximately 4700 deg R at this high thrust condition. Water and/or oxygen injection are simple and straightforward strategies to improve engine performance and they will add little to engine weight. However, if large Mach number and thrust increases are required, liquid flows become significant, so that operation at these conditions will necessarily be of short duration

History, current status, and collaborative researchprojects for Bemisia tabaci

Bemisia tabaci was described over 100 years ago and has since become one of the most important pests worldwide in subtropical and tropical agriculture as well as in greenhouse production systems. It adapts easily to new host plants and geographical regions and has now been reported from all global continents except Antarctica. In the last decade, international transport of plant material and people have contributed to geographical spread. B. tabaci has been recorded from more than 600 plant species and there may be many additional hosts not yet formally documented. Biotypes have been identified in different areas of the world suggesting that B. tabaci may be a species-complex undergoing evolutionary change. These biotypes may exhibit differences in viruses transmitted and transmission efficiency, rates of development, endosymbionts, host utilization, and physiological host damage. Excessive B. tabaci induced losses worldwide occur in field, vegetable and ornamental crop production. Losses occur from plant diseases caused by B. tabaci transmitted viruses, direct feeding damage, plant physiological disorders, and honeydew contamination and associated fungal growth. The number of B. tabaci-transmitted plant viruses has increased, and total yield losses of important food and industrial crops has occurred. Effective control at present is dependent on insecticides. However, this has been achieved with more selective chemistries, use of action thresholds, and resistance management. Host plant resistance and various cultural methods are also components of developing integrated management systems. National and international collaborative projects have made significant progress towards improved characterization of the whitefly problem, increased research, development of management methods, transfer of technology to the agricultural communities, and information exchange. These projects, as well as intensive education, research and extension activities form the basis for biologically and ecologically based approaches to management

Qualitative and quantitative analysis of lipid classes in fish oils by thin-layer chromatography with an Iatroscan flame Ionization detector (TLC-FID) and liquid chromatography with an evaporative light scattering detector (LC-ELSD)

Combined effects of hydrogen and air flow rates on the peak response of selected neutral lipid classes (triacylglycerol, diacylglycerol, monoacylglycerol, free fatty acids, and ethyl esters) were studied to optimize and calibrate the Iatroscan Mk-6s Chromarod system for the qualitative and quantitative analysis of lipid classes by thin-layer chromatography (TLC) with flame ionization detection in fish oil during the transesterification process. Air flow rate of 2 L/min, hydrogen flow rate of 150-160 mL/min, and scan rate of 30 s/rod were found to be the optimum conditions. All samples were also analyzed by high performance liquid chromatography (HPLC) with evaporative light scattering detection. Quantitative results obtained by TLC with the flame ionization detection method were comparable to those obtained from HPLC with evaporative light scattering detection. <br /

Organic and Conventional Vegetable Production in Oklahoma

This study compares he profitability and risk related to conventional and organic vegetable production systems A linear programming model was used to find the optimal mix of vegetables in both production systems. And a target MOTAD (minimization of total absolute deviation) model was used to perform risk analysis in both organic and conventional production systemsCrop Production/Industries, Research Methods/ Statistical Methods,

Impediments to U.S. wheat exports and reasons for decline in world market share

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311