Limitations on wind-tunnel pressure signature extrapolation

Analysis of some recent experimental sonic boom data has revived the hypothesis that there is a closeness limit to the near-field separation distance from which measured wind tunnel pressure signatures can be extrapolated to the ground as though generated by a supersonic-cruise aircraft. Geometric acoustic theory is used to derive an estimate of this distance and the sample data is used to provide a preliminary indication of practical separation distance values

A methodology for designing aircraft to low sonic boom constraints

A method for designing conceptual supersonic cruise aircraft to meet low sonic boom requirements is outlined and described. The aircraft design is guided through a systematic evolution from initial three view drawing to a final numerical model description, while the designer using the method controls the integration of low sonic boom, high supersonic aerodynamic efficiency, adequate low speed handling, and reasonable structure and materials technologies. Some experience in preliminary aircraft design and in the use of various analytical and numerical codes is required for integrating the volume and lift requirements throughout the design process

A practical low-boom overpressure signature based on minimum sonic boom theory

A brief resume of sonic boom minimization methods is given to provide a background for a new, empirical modification of the Seebass and George minimum-nose-shock sonic boom F-function and signature. The new 'hybrid' F-function has all the inherent flexibility of application found with the Darden-modified Seebass and George F-function. In addition, it has enhanced this flexibility and applicability with neglegible increase in nose and/or tail shock strength. A description of this 'hybrid' F-function and signature is provided, and the benefits of using them to design high-performance, low-boom aircraft are discussed

Estimates of genetic variability in the F4 generation of three populations of common wheat (Triticum aestivum L. Em. Thell.)

Three populations of common bread wheat (Triticum aestivum L. em. Thell.) were studied to gain an estimate of the genetic variability associated with four agronomic characters in each population. The primary objective was to determine if homozygous lines could be isolated from these populations that would be equal to or better than the F1 of the respective population. Two populations (population 1 and 3) exhibited heterosis for yield in the F1 generation while the other population (population 2) showed no heterosis for yield in the F1. Each population consisted of random F4 lines, each of which could be traced to a single F2 plant. Population 1 originated from a cross of the cultivars \u27Seneca\u27 x \u27Knox 62\u27; population 2 from a cross of \u27Monon\u27 x \u27Triumph\u27; and population 3 from a cross of \u27Tenn. 9\u27 x \u27Knox 62\u27. The characters studied were: (1) mature plant height (centimeters), (2) heading date (days past March 31), (3) yield (grams per plot), and (4) kernel weight (grams per 1000 kernels). The experimental design was a randomized com-plete block with two replications and the experiment was grown at three locations. Estimates of broad sense heritability were obtained via variance component analyses. These heritability estimates were used to calculate expected advance through selection for each character in each population. Phenotypic and genotypic correlation coefficients for all characters in all combinations were calculated. Coefficients of variation and genetic coefficients of variation were also computed. Analyses of the data revealed that the non-heterotic population (population 2) had significant (P. = .05) variability for all four characters. Population 1 showed significant (P. = .05) variability for heading date and kernel weight only, and population 3, for only heading date and mature plant height. Heading date in population 3, mature plant height and kernel weight in population 2 were the only characters whose expected F5 means would be better than the best parent. Evidence was found to support a two major gene hypothesis for the inheritance of heading time. From the results of this study, it appears that homozygous lines that equal or better the F1 could not be found in later generations

Some considerations on the integration of engine nacelles into low-boom aircraft concepts

A study of wind-tunnel data has shown why unexpected strong shock waves appeared in wind tunnel pressure signatures of two low-boom models, and has indicated that changes to the current methods for analyzing and designing low-boom aircraft are needed. The discussion provided corrections for the interface lift code, and suggested methods of treatment for the equivalent areas of the aircraft, especially the nacelles and the interference lift, which were to be used in the aircraft design and the sonic boom analysis

Why Biography?

Reading for Pleasure (Essay Review

Rethinking the dynamics of capital accumulation in colonial and post-colonial Indonesia: Production Regulation

This thesis explores the forces driving a series of momentous transformations to Indonesia�s production and distribution systems since early colonial rule. The analysis of these forces is anchored in four conceptual themes: the basis of these systemic transformations, their politico-economic ordering as driven by a surplus-creation imperative, labour�s role in this imperative and its response to the �ordering�, and the mode of production as the historical setting within which the transformations occur. This thesis illuminates an analytical gap in the literature by nominating labour as the key force in wealth-creation and recognising its active role in challenging ruling appropriation regimes and in the broader social struggles against exploitation and oppression. The thematic focus defines the boundaries for an exploration of successive colonial and post-colonial ruling regimes. Early chapters examine how the Dutch penetrated the Indonesian politico-economy, entrenching their systems of production organisation and creating an exclusionary system of wealth appropriation. Appropriation systems are characterised by transitions in European political and economic systems, especially from mercantilism to industrial capitalism. The entrenchment of colonial power is considered in relation to the expansion of capitalist organisation in Indonesia. The state�s stimulation of this expansion is associated with an undermining of the country�s reproductive base and a growing challenge to foreign rule. The Japanese occupying force� demolition of colonial productive and distributive linkages and encouragement of independence activism is connected with a post-war struggle for independence. Links are drawn between colonial rule and the tensions and organisational difficulties faced by Republican regimes leading up to the New Order�s re-establishment of a strict regulatory regime, and the development of an indigenous system of capitalist organisation. The surplus-generation and appropriation perspective informs the evolution of Indonesia�s productive and economic systems across colonial and post-colonial epochs and the challenges to the system of social and production regulation that heralded the destabilisation of New Order rule and the rise of the contemporary era of political democracy

Extensive Green Roofs in Mississippi: An Evaluation of Stormwater Retention under Local Climatic Conditions

Green roofs are increasingly being used in the United States to mitigate the negative effects of impervious surfaces on aquatic ecosystems. Though performance of these systems varies with climate, little research has been conducted in the Southeastern U.S., and no prior research has been conducted in Mississippi. An experiment was conducted to determine the effect of soil depth and roof slope on the stormwater retention of green roofs in Mississippi’s hot, humid climate. Simulated roof platforms were constructed to investigate two soil depths and two slopes, each replicated three times and planted with four species of Sedum. The green roof platforms significantly reduced runoff depth when compared with total rainfall depth. Soil depth and slope both significantly affected retention, with higher retention seen with increasing soil depth and lower retention seen with increasing slope. These results indicate that green roofs can be an effective tool to reduce runoff in Mississippi

Relationship Between 6- Mercaptopurine Toxicity And Uric Acid Synthesis In The Chick

Six-mercaptopurine is a chemotherapeutic drug which has been used extensively in clinical research as well as biological and biochemical experimental studies. Studies on the absorption, distribution, toxicity, and metabolism of 6-mercaptopurine (6-MP) in experimental animals and in the human have been reported in recent reviews. The extreme toxicity of 6-MP and its analogs have been observed in various species. Phillips (1954) reported that toxicity occurs in rabbits at a dosage level of 10 to 15 mg/ kg bdy wt/day, while 100 mg/kg bdy wt/day may be required to produce similar effects in guinea pigs. According to Hamilton and Elion (1954), toxicity often appears in man at a dosage of 2.5 mg/kg bdy wt/day. The toxicity of this purine and its derivatives has imposed obvious limitations in their use for treatment of leukemia. Studies in our laboratory during the past year have demonstrated that the chick can tolerate 1200-1800 mg/kg bdy wt/ day of 6-MP. The writer could find no report of any investigation which involved the chick in regard to the unusual relative high tolerance of this compound, nor any reference to the metabolic degradation of this purine or its derivatives in this species. The present status of research in this area has indicated that the therapeutic effectiveness of 6-MP and other purine derivatives, may be potentiated in man. It has been established that the end product of purine metabolism in man and in the chick is uric acid, although it is excreted in much larger amounts in the chick. In view of the chick\u27s normal high tolerance for 6-MP, it seems logical to assume that this species may possess a mechanism which enables it to normally detoxify the oxidative metabolic end-products associated with the degradation of 6-MP and other derivatives more efficiently than man or other previously studied species