Computation of nozzle flow fields using the PARC2D Navier-Stokes code

Supersonic nozzles which operate at low Reynolds numbers and have large expansion ratios have very thick boundary layers at their exit. This leads to a very strong viscous/inviscid interaction upon the flow within the nozzle and the traditional nozzle design techniques which correct the inviscid core with a boundary layer displacement do not accurately predict the nozzle exit conditions. A full Navier-Stokes code (PARC2D) was used to compute the nozzle flow field. Grids were generated using the interactive grid generator code TBGG. All computations were made on the NASA MSFC CRAY X-MP computer. Comparison was made between the computations and in-house wall pressure measurements for CO2 flow through a conical nozzle having an area ratio of 40. Satisfactory agreement existed between the computations and measurements for a stagnation pressure of 29.4 psia and stagnation temperature of 1060 R. However, agreement did not exist at a stagnation pressure of 7.4 psia. Several reasons for the lack of agreement are possible. The computational code assumed a constant gas gamma whereas gamma for CO2 varied from 1.22 in the plenum chamber to 1.38 at the nozzle exit. Finally, it is possible that condensation occurred during the expansion at the lower stagnation pressure

Rule-based cloud service localisation

The fundamental purpose of cloud computing is the ability to quickly provide software and hardware resources to global users. The main aim of cloud service localisation is to provide a method for facilitating the internationalisation and localisation of cloud services by allowing them to be adapted to different locales. We address lingual localisation by providing a service translation using the latest web-services technology to adapt services to different languages and currency conversion by using realtime data provided by the European Central Bank. Units and Regulatory Localisations are performed by a conversion mapping, which we have generated for a subset of locales. The aim is to provide a standardised view on the localisation of services by using runtime and middleware services to deploy a localisation implementation

2nd generation concrete construction: carbon footprint accounting

Purpose – Construction contractors and facility managers are being challenged to minimize the carbon footprint. Life cycle carbon‐equivalent (CO2‐e) accounting, whereby the potential emissions of greenhouse gases due to energy expenditure during construction and subsequent occupation of built infrastructure, generally ceases at the end of the service life. However, following demolition, recycling of demolition waste that becomes incorporated into 2nd generation construction is seldom considered within the management of the carbon footprint. This paper aims to focus on built concrete infrastructure, particularly the ability of recycled concrete to chemically react with airborne CO2, thereby significantly influencing CO2‐e estimates.Design/methodology/approach – CO2‐e estimates were made in accordance with the methodology outlined in the Australian National Greenhouse Accounts (NGA) Factors and were based on the energy expended for each life cycle activity from audited records. Offsets to the CO2‐e estimates were based on the documented ability of concrete to chemically react with airborne carbon dioxide (“carbonation”) and predictions of CO2 uptake by concrete and recycled concrete was made using existing predictive diffusion models. The author\u27s study focused on a built concrete bridge which was demolished and recycled at the end of the service life, and the recycled concrete was utilized towards 2nd generation construction. The sensitivity of CO2‐e and carbonation estimates were tested on several different types of source demolition waste as well as subsequent construction applications using recycled concrete (RCA). Whole‐of‐life CO2‐e estimates, including carbonation of RCA over the 1st and 2nd generations, were estimated and contrasted with conventional carbon footprints that end at the conclusion of the 1st generation.Findings – Following demolition, CO2 capture by RCA is significant due to the more permeable nature of the crushed RCA compared with the original built infrastructure. RCA also has considerably greater exposed surface area, relative to volume, than a built concrete structure, and therefore more highly exposed surface to react with CO2: it therefore carbonates more comprehensively. CO2‐e estimates can be offset by as much as 55‐65 per cent when including the contribution of carbonation of RCA built within 2nd generation infrastructure. Further offsets are achievable using blended fly ash or slag cement binders; however, this study has focused on concrete composed of 100 per cent OPC binders and the effects of RCA.Originality/value – Construction project estimates of life cycle CO2‐e emissions should include 2nd generation applications that follow the demolition of the 1st generation infrastructure. Life cycle estimates generally end at the time of demolition. However, by incorporating the recycled concrete demolition waste into the construction of 2nd generation infrastructure, the estimated CO2‐e is significantly offset during the 2nd generation life cycle by chemical uptake of CO2 (carbonation). This paper provides an approach towards inclusion of 2nd generation construction applications into whole‐of‐life estimates of CO2‐e

Preferences and interests of pupils in junior high school science classes

Thesis (Ed.M.)--Boston University, 1949. This item was digitized by the Internet Archive

THE TAXONOMIC STATUS OF THE WYOMING TOAD, BUFO BAXTERI PORTER

The population of toads in southeastern Wyoming named Bufo hemiophrys baxteri by Porter in 1968 is presumed to be extinct in nature, except perhaps for released, captive-bred specimens. It is sufficiently distinct in several respects, and sufficiently isolated geographically from its nearest rela- tive, B. h. hemiophrys, that it should be regarded as a distinct species, forming a superspecies group with B. hemiophrys

Part I. A Novel Synthesis of Dihydrojasmone. Part II. Polymethyleneketenedimers and Trimers.

Part I. A Novel Synthesis of Dihydrojasmone. — 3-Methylcyclopent-2-en-2-ol-l-one, a readily available substance of natural occurrence, was utilized in the synthesis of the well-known dihydrojasmone (2-n-aniyl-3-methylcyclopent-2-en-l-one). This was the first practical synthesis of dihydroJasmone which did not involve a condensation reaction, thus the possibility of obtaining an isomeric mixture of products was eliminated. Acetylation of 3-methylcyclopent-2-en-2-ol-l-one with acetic anhydride gave 2-acetoxy-3-methylcyclopent-2-en-l-one, which was converted by the action of propylene oxide to 2-acetoxy-3-methylcyclopent-2-en-l-one propylene ketal. Saponification of this ketal gave 3- methyl-l,2-cyclopentanedione-l,l-propylene ketal, which served as a precursor to dihydrojasmone. Upon treatment of this compound with n-amylmagnesium chloride, followed by hydrolysis with ammonium chloride solution, 2-n-amyl-3-methylcyclopentan-2-ol-l-one propylene ketal was obtained. Dehydration and deketalization of the latter compound with sulfuric acid solution yielded dihydrojasmone. Part II. Polymethyleneketene Dimers and Trimers. — An excellent method for the preparation of ketoketene dimers involves the dehydrohalogenation of an acyl chloride with triethylamine. The reaction of cyclopropanecarbonyl chloride with triethylamine gave no dimer but instead a solid product, presumably the acyl ammonium chloride, which reacted with aniline to form cyclopropanecarboxanilide. Cyclobutanecarbonyl chloride and triethylamine yielded at temperatures below 25® a similar addition compound which gave cyclobutanecarboxanilide when treated with aniline. When the latter reaction was carried out at a higher temperature, dispiro [3.1.3.1] decane-5,10-dione was obtained. Dispiro [3.1.3.1] decane-5,10-dione, trimethyleneketene dimer, underwent cleavage and decarboxylation in alkali to give dicyclobutyl ketone. The ketone was obtained without acidification of the alkaline solution, which is generally necessary for the decarboxylation of a β-keto acid in the form of its sodium salt. A mechanism was proposed for its formation. Trimethyleneketene dimer reacted with ethanol in the presence of a catalytic amount of base to give ethyl l- (cyclobutanecarbonyl)cyclobutanecarboxylate, and was reduced to the corresponding glycol, dispiro [3.1.3.1] decane-5,10-diol with lithium aluminum hydride. It is known that dimethylketene dimer, tetramethyl-l,3-cyclobutanedione, when treated with a catalytic amount of sodium methoxide, yields the cyclic trimer, hexamethyl-l,3,5-cyclohexanetrione. In the present investigation, this base-catalyzed process was utilized in the synthesis of trimethyleneketene trimer, trispiro [3.1.3.1.3.1] pentadecane-5,10,15-trione, from trimethyleneketene dimer. In this study it was found that the alkaline hydrolysis of dimethylketene trimer with barium hydroxide gave 2,4,4,6-tetramethylheptan-3,5-dione. Trimethyleneketene trimer, upon treatment with the same reagent gave l, l (dicyclobutanecarb6nyl) cyclobutane and dicyclobutyl ketone. Ethanolysis of trimethyleneketene trimer gave ethyl 1-[1-(cyclobutanecarbonyl)cyclobutanecarbonyl] cyclobutanecarboxylate. Reduction of the trimer was accomplished with lithium aluminum hydride to give trispiro [3.1.3.1.3.1] pentadecane-5,10,15- triol. Tetramethyleneketene dimer, dispiro [4.1.4.1] dodecane-6,12-dione, a known compound, was the only product isolated in an attempted synthesis of tetramethyleneketene monomer by dehydrohalogenation of cyclopentanecarbonyl chloride with triethylamine. The dimer underwent cleavage and decarboxylation when treated with alkali to give dicyclopentyl ketone. Only one polymethylene ketene, pentamethyleneketene, has been reported in the literature. It was found that hexamethyleneketene could be synthesized by dehydrohalogenation of cycloheptanecarbonyl chloride with triethylamine. This monomer reacted with aniline to give cycloheptanecarboxanilide, and gave with cyclopentadiene a cycloaddition product, hexamethylenebicyclo [3.2.0] hept-3-en-l-one. Hexamethyleneketene dimerized upon standing to give dispiro- [6.1.6.1] hexadecane-8, l6-dione which underwent reduction with lithium aluminum hydride to give the corresponding glycol, dispiro [6.1.6.1] hexadecane-8,l6- triol

Can emerging African Stock Markets improve their informational efficiency by formally harmonising and integrating their operations?

Despite experiencing rapid growth in their number and size, African stock markets remain highly segmented, small, illiquid and technologically bankrupt, severely affecting their informational efficiency. On this basis, with specific focus on the weak-form of the efficient markets hypothesis, we attempt to empirically ascertain whether African stock markets can improve their informational efficiency by formally harmonising and integrating their operations using a new robust non-parametric variance-ratios test in addition to its parametric alternative. On average, we find that irrespective of the diagnostic used, all the 24 African continent-wide indices applied returns’ display better normal distribution properties than those of the 8 individual national stock price indices examined. We record evidence of statistically significant improvements in the informational efficiency of the African continent-wide stock price indices over the individual national stock price indices used irrespective of the test statistic applied. The potential improvement in efficiency to be gained is much higher in economic sectors indices than in size and regional indices. Finally, consistent with prior evidence, (eg., Wright, 2000; Belaire-Franch and Opong, 2005, Ntim, et al., 2007), the results of the Lo and MacKinlay (1988) parametric variance-ratios test are ambiguous. By contrast, the ranks and signs alternative offer consistent results throughout.African stock markets, Integration, Efficiency, Variance-ratios, Ranks and signs

Servicescape And Customers’ Willingness-To-Pay For Vehicle Repairs And Maintenance Services

This research work investigates into the servicescape and customers’ willingness to pay for mechanical services at the Suame Magazine in the Kumasi Metropolis. The study adopted descriptive survey method and the target population was the mechanics and customers of mechanical services in the Suame Magazine in the Kumasi Metropolis. The study conveniently sampled 150 customers who patronize the services of the small scale auto mechanics who repair and maintain vehicles. Questionnaire was used to collect data from the customers. It was realized that signs, symbols and artifacts were not important to customers who go to the Suame Magazine for mechanical services but customers’ perceived ambient conditions and spatial layout as important to them. Customers disagree that Suame Magazine smell badly but they attested that the Suame Magazine is noisy. Suame Magazine has good layout but customers attested that the industrial enclave is always congested. Majority of customers’ relatively perceived charges or price of mechanical services to be relatively as expected and majority (58.0%) of the customers were willing to pay for mechanical services at the Suame Magazine. The customers’ willingness to pay for mechanical services depends on the servicesscape in the Suame Magazine. Mechanical garages with good ambient and spatial layout would have high patronage. The study recommends that mechanics in the Suame Magazine should strategically use servicescape as marketing tool for effective pricing which can influence customer willingness to pay for their services. The mechanical garages should have servicescape policy with specific emphasis on spatial layout and ambient conditions

Global Analysis of Fragmentation Functions for Eta Mesons

Fragmentation functions for eta mesons are extracted at next-to-leading order accuracy of QCD in a global analysis of data taken in electron-positron annihilation and proton-proton scattering experiments. The obtained parametrization is in good agreement with all data sets analyzed and can be utilized, for instance, in future studies of double-spin asymmetries for single-inclusive eta production. The Lagrange multiplier technique is used to estimate the uncertainties of the fragmentation functions and to assess the role of the different data sets in constraining them.Comment: 11 pages, 8 figures, updated reference