42,781 research outputs found
Effect of grooved casing treatment on the flow range capability of a single-stage axial-flow compressor
Comparisons of the results of testing a single-stage axial-flow compressor with a solid-wall casing and with grooved casings are presented. The depth, location, and number of circumferential grooves in the casing over the casing over the rotor tip were varied. The near-stall weight flow was lower than that with the solid-wall casing for all but one grooved configuration indicating an improvement in the stall margin. The greatest reduction in the near-stall weight flow was noted for the configuration with five grooves located over the blade midchord region
Broadening access to earth science information for education in the UK
The presentation describes strategies for enhancing earth science teaching through inspiring role-play and long-term experiments. Over the past decade there has been a growing concern that earth sciences are often poorly served in UK schools. In parallel with this there has been a general decline in the number of students choosing science. The government's response has been a number of initiatives designed to stimulate interest in scientific careers and enhance the learning experience. Over the same period, UK and European government alongside popular campaigns have encouraged the release of national datasets for educational purposes. The British Geological Survey (BGS) has an international reputation in the delivery of data for professional geologists and is now building a portfolio of projects based on free, convenient access to digital data alongside face-to-face contact with inspirational role models with the aim of introducing exciting, relevant science to schools. The UK-wide School Seismology Project provides a specially designed instrument records earthquakes from anywhere on the globe and the data may be shared through a web portal. Schools receive training, sponsorship and practical support. Students benefit from the experience of collecting unique data and opportunities to report their findings via local press and TV. Sister projects are running in Ireland and Africa. STEM Ambassadors provide a wide range of in-school support, from simple experiments to careers advice and mentoring. Our most requested activities include 'Seconds from Catastrophe?' and 'Quarry or Not?'. In these, students take on the roles of scientists, government officials and residents and vigorously debate, respectively, the issues involved in planning an emergency response to a volcanic eruption and the environmental impacts of the extractive industry. Real data are analysed and an important feature is that the facilitators have genuine experience of the scenarios
An in-flight investigation of pilot-induced oscillation suppression filters during the fighter approach and landing task
An investigation of pilot-induced oscillation suppression (PIOS) filters was performed using the USAF/Flight Dynamics Laboratory variable stability NT-33 aircraft, modified and operated by Calspan. This program examined the effects of PIOS filtering on the longitudinal flying qualities of fighter aircraft during the visual approach and landing task. Forty evaluations were flown to test the effects of different PIOS filters. Although detailed analyses were not undertaken, the results indicate that PIOS filtering can improve the flying qualities of an otherwise unacceptable aircraft configuration (Level 3 flying qualities). However, the ability of the filters to suppress pilot-induced oscillations appears to be dependent upon the aircraft configuration characteristics. Further, the data show that the filters can adversely affect landing flying qualities if improperly designed. The data provide an excellent foundation from which detail analyses can be performed
Prompt Photon plus Charm Production at Next-to-Leading Order in QCD
The two particle inclusive cross section for the reaction is studied in perturbative quantum
chromodynamics at order . Differential distributions are
provided for various observables, and a comparison is made with data from the
CDF collaboration.Comment: 4 pages, LaTeX, uses stwol.sty, 6 postscript figures. Invited paper
presented by E. L. Berger at the 28th International Conference on High Energy
Physics, Warsaw, Poland, July 25 - 31, 199
Allelic variants of KLK2 gene predict presence of prostate cancer at biopsy
Objective: Several single nucleotide polymorphisms associated with prostate cancer risk have been reported in recent years. We evaluated polymorphisms in the human glandular kallikrein 2 (KLK2) genes because the protein product of this gene is known to be increased in prostate cancer.
Materials and methods: Blood samples were collected from sixty patients who underwent prostate biopsy sectioning, and from their genomic DNA the SNPs in KLK2 gene were investigated by direct DNA sequencing. Another 138 archived prostate tissue sections were also evaluated using the TaqMan SNP genotyping assay.
Results: Eighteen known SNPs were identified in the KLK2 gene. The SNPs were located in introns, coding exons and untranslated regions of the gene. Further analysis showed that two of the SNPs were associated with prostate disease. The T/T allele of rs198977 was significantly predictive of the presence of prostate cancer at biopsy and was also associated with high tumour grade. The A/A allele of rs2664155 was also significantly associated with the presence of benign hyperplasia at biopsy.
Conclusion: Our results support previous reports of association of the rs198977 SNP with prostate cancer risk and also indicated a link with the disease phenotype. However, the second SNP (rs2664155) was more associated with benign hyperplasia than prostate cancer risk. The method of TaqMan SNP genotyping could be clinically useful in genetic screening and risk stratification of patients for prostate diseases
Associated Production of Charm and a Hard Photon
The two particle inclusive cross section for the reaction is studied in perturbative quantum
chromodynamics at order , for large values of the transverse
momentum of the prompt photon and charm quark. Two different techniques are
used in performing the phase-space integrals; the first is purely analytical,
and the second is a combination of analytic and Monte Carlo integration
methods. The second, more versatile technique facilitates imposition of photon
isolation restrictions and other selections of relevance in experiments.
Differential distributions are provided for various observables, and a
comparison is made with preliminary data from the CDF collaboration.Comment: 6 pages. Latex file plus 4 ps files of figures submitted togther in
uuencoded form; invited talk presented by L. E. Gordon at the XXXI Rencontres
de Moriond on QCD and High Energy Hadronic Interactions, Les Arcs, France,
March, 199
Static-pressure contours in the blade passage at the tip of several high Mach number rotors
Static pressure contours of turbine rotor blade tips at high Mach number
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