Comparison of two- and three-dimensional flow computations with laser anemometer measurements in a transonic compressor rotor

Two and three dimensional inviscid solutions for the flow in a transonic axial compressor rotor at design speed are compared with probe and laser anemometers measurements at near-stall and maximum-flow operating points. Experimental details of the laser anemometer system and computational details of the two dimensional axisymmetric code and three dimensional Euler code are described. Comparisons are made between relative Mach number and flow angle contours, shock location, and shock strength. A procedure for using an efficient axisymmetric code to generate downstream pressure input for computationally expensive Euler codes is discussed. A film supplement shows the calculations of the two operating points with the time-marching Euler code

Time-partitioning simulation models for calculation on parallel computers

A technique allowing time-staggered solution of partial differential equations is presented in this report. Using this technique, called time-partitioning, simulation execution speedup is proportional to the number of processors used because all processors operate simultaneously, with each updating of the solution grid at a different time point. The technique is limited by neither the number of processors available nor by the dimension of the solution grid. Time-partitioning was used to obtain the flow pattern through a cascade of airfoils, modeled by the Euler partial differential equations. An execution speedup factor of 1.77 was achieved using a two processor Cray X-MP/24 computer

A diagonally inverted LU implicit multigrid scheme

A new Diagonally Inverted LU Implicit scheme is developed within the framework of the multigrid method for the 3-D unsteady Euler equations. The matrix systems that are to be inverted in the LU scheme are treated by local diagonalizing transformations that decouple them into systems of scalar equations. Unlike the Diagonalized ADI method, the time accuracy of the LU scheme is not reduced since the diagonalization procedure does not destroy time conservation. Even more importantly, this diagonalization significantly reduces the computational effort required to solve the LU approximation and therefore transforms it into a more efficient method of numerically solving the 3-D Euler equations

Below- and above-ground tree species diversity in natural forest and monoculture tree plantations at Omo Biosphere Reserve, Nigeria

The conversion of natural forests to monoculture tree plantations (MTPs) has been known to reduce above-ground tree diversity. However, information is lacking on the impact of MTPs on below-ground tree species diversity. This study evaluated below- and above-ground tree species diversity in a Strict Nature Reserve (SNR), a monoculture plantation of an indigenous tree species – Nauclea diderrichii (Nd), and four MTPs of exotic species – Gmelina arborea (Ga), Tectona grandis (Tg), Pinus caribaea (Pc) and Theobroma cacao (Tc) within Omo Biosphere Reserve in South-western Nigeria. Below-ground tree species was ascertained by evaluating the soil seed banks from the natural forest and the monoculture plantations using the seedling emergence method while tree species enumeration aboveground was done using the quadrat method. Below- and above-ground tree species diversity was higher in the SNR than in the MTPs and higher in the MTP of indigenous species (Nd) than in those of the exotic species. Below-ground tree species diversity was zero in both the SNR and MTPs below 0-5 cm soil depth. Similarity in tree species composition was also higher between the SNR and the indigenous species (Nd) plantation. The negative impact of natural forest conversion to MTPs on below- and above-ground tree species diversity was found to be lower in the indigenous species (Nd) plantation than in the exotic species (Ga, Tg, Pc & Tc) plantations. Consequently, plantation forestry may consider native species for biodiversity restoration.Keywords: Forest conversion, species origin, regeneration potential, tree diversit

SWIFT Code Assessment for Two Similar Transonic Compressors

One goal of the NASA Fundamental Aeronautics Program is the assessment of computational fluid dynamic (CFD) codes used for the design and analysis of many aerospace systems. This paper describes the assessment of the SWIFT turbomachinery analysis code for two similar transonic compressors, NASA rotor 37 and stage 35. The two rotors have identical blade profiles on the front, transonic half of the blade but rotor 37 has more camber aft of the shock. Thus the two rotors have the same shock structure and choking flow but rotor 37 produces a higher pressure ratio. The two compressors and experimental data are described here briefly. Rotor 37 was also used for test cases organized by ASME, IGTI, and AGARD in 1994-1998. Most of the participating codes over predicted pressure and temperature ratios, and failed to predict certain features of the downstream flowfield. Since then the AUSM+ upwind scheme and the k- turbulence model have been added to SWIFT. In this work the new capabilities were assessed for the two compressors. Comparisons were made with overall performance maps and spanwise profiles of several aerodynamic parameters. The results for rotor 37 were in much better agreement with the experimental data than the original blind test case results although there were still some discrepancies. The results for stage 35 were in very good agreement with the data. The results for rotor 37 were very sensitive to turbulence model parameters but the results for stage 35 were not. Comparison of the rotor solutions showed that the main difference between the two rotors was not blade camber as expected, but shock/boundary layer interaction on the casing

On The Problem of Special Theory of Relativity According to Albert Einstein

This paper re-examiners the principle of special theory of relativity according to Albert Einstein, which states that, “the speed of light in vacuum is the same in all inertial frames of reference”. This postulate is a misconception. If the speed of light can be reduced in certain medium, then there should be no restriction to the speed of light exceeding “c” in other medium /reference. The conceptual “time dilation” and “length contraction” are misconceptions; they are intrinsically the same classical concepts of the refraction of light. The resultant refractive index can be used to predict speed moving beyond “c”. Keywords: Time dilation ,Length Contraction, Speed of Light and Relativity

STRATEGIC IMPERATIVES OF SOCIAL ENTREPRENEURSHIP ON SOCIAL PERFORMANCE

This study examined the effect of social entrepreneurship on the social performance of enterprises operating in Nigeria. The study adopted a quantitative method. Specifically 200 copies of structured questionnaire were distributed to ten social enterprises operating in Nigeria. Based on the results of the regression analysis, findings show that of all measures of social entrepreneurship, social innovation has the highest potential to improve the social performance of a firm. It is thus recommended that firms operating specifically in developing countries that are characterized by institutional challenges should place emphasis on ensuing they continually produce socially innovative processes and procedures

Library Internet Use and Demographic Characteristics of Undergraduates in a Nigerian University: Uncovering the Areas of Need.

This study investigated undergraduates of Federal University of Technology Owerri, Nigeria to ascertain whether their demographic profile was a characteristic of library internet usage. Data used for the study was a textual analysis of statistic register on library internet use from May 2017 – June 2018. The study population consisted of 2682 valid name entries during the period under study. Findings revealed that FUTO has greater number of male undergraduates and this is due to the academic structure of the institution.  Discipline wise demographic characteristics showed that undergraduates from Agricultural Economics made most use of the library internet in School of Agriculture and Agricultural Technology (SAAT) while those in department of Electrical and Electronics Engineering (EEE) were the most users in School of Engineering and Engineering Technology (SEET). Also, undergraduates from Information Management Technology (IMT) and Project Management Technology (PMT) used the internet most in School of Management Technology (SMAT) while those in Biotechnology (BIO) were the most users in School of Biological Sciences (SOBS). Further findings revealed that undergraduates from Surveying and Geoinformatics (SVG) were the most library internet users in School of Environmental Technology (SOET) while Biomedical Technology undergraduates (BMT) made use of the internet more than their counterparts in the School of Health Technology (SOHT). Similarly, Computer Science (CSC) students used the internet most in School of Physical Sciences (SOPS). On the overall faculty level, School of Engineering and Engineering Technology (SEET) made most use of the library internet than other Schools. In terms of study level, it was revealed that final year (500 level) students used the library internet most. Having uncovered the disparity in library internet use, the study recommends among others that embedded librarians in FUTO should promote library operations and services through constant connection and communication with their various departments, continuous marketing and awareness creation of the library’s internet facility. Keywords: Academic library, Internet, Demographic characteristics, FUTO, Undergraduates, Nigerian University, Schools. DOI: 10.7176/IKM/10-2-08 Publication date: March 31st 202

The relationship of female physical attractiveness to body fatness

Funding This work was supported by NSFC grant 91431102 from the National Science Foundation of China. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Acknowledgements We are grateful to all the participants from all the countries and all the members of Molecular Energetics Group for their help on the investigation and discussion of the results.Peer reviewedPublisher PD

Analysis of Inlet-Compressor Acoustic Interactions Using Coupled CFD Codes

A problem that arises in the numerical simulation of supersonic inlets is the lack of a suitable boundary condition at the engine face. In this paper, a coupled approach, in which the inlet computation is coupled dynamically to a turbomachinery computation, is proposed as a means to overcome this problem. The specific application chosen for validation of this approach is the collapsing bump experiment performed at the University of Cincinnati. The computed results are found to be in reasonable agreement with experimental results. The coupled simulation results could also be used to aid development of a simplified boundary condition