Effect of Reynolds Number and Periodic Unsteady Wake Flow Condition on Boundary Layer Development, Separation, and Re-attachment along the Suction Surface of a Low Pressure Turbine Blade

The paper experimentally studies the effects of periodic unsteady wake flow and different Reynolds numbers on boundary layer development, separation and re-attachment along the suction surface of a low pressure turbine blade. The experimental investigations were performed on a large scale, subsonic unsteady turbine cascade research facility at Turbomachinery Performance and Flow Research Laboratory (TPFL) of Texas A&M University. The experiments were carried out at Reynolds numbers of 110,000 and 150,000 (based on suction surface length and exit velocity). One steady and two different unsteady inlet flow conditions with the corresponding passing frequencies, wake velocities, and turbulence intensities were investigated. The reduced frequencies chosen cover the operating range of LP turbines. In addition to the unsteady boundary layer measurements, surface pressure measurements were performed. The inception, onset, and the extent of the separation bubble information collected from the pressure measurements were compared with the hot wire measurements. The results presented in ensemble-averaged, and the contour plot forms help to understand the physics of the separation phenomenon under periodic unsteady wake flow and different Reynolds number. It was found that the suction surface displayed a strong separation bubble for these three different reduced frequencies. For each condition, the locations defining the separation bubble were determined carefully analyzing and examining the pressure and mean velocity profile data. The location of the boundary layer separation was dependent of the Reynolds number. It is observed that starting point of the separation bubble and the re-attachment point move further downstream by increasing Reynolds number from 110,000 to 150,000. Also, the size of the separation bubble is smaller when compared to that for Re=110,000

New optimization methods in Data Mining

Data mining is a modern area of science dealing with the learning from given data in order to make predictions and estimations. Applications of Data mining can be found in various areas of academical and non academical life. This paper introduces new contributions by continuous optimization as a key technology in data mining. The methods suggested for solution of such important problems as clustering and classification, were recently obtained by the authors in collaboration with members of EURO working group EUROPT

Metalorganic chemical vapor deposition growth and thermal stability of the AllNN/GaN high electron mobility transistor structure

Cataloged from PDF version of article.The AlxIn1-xN barrier high electron mobility transistor (HEMT) structure has been optimized with varied barrier composition and thickness grown by metalorganic chemical vapor deposition. After optimization, a transistor structure comprising a 7 nm thick nearly lattice-matched Al0.83In0.17 N barrier exhibits a sheet electron density of 2.0 x 10(13) cm(-2) with a high electron mobility of 1540 cm(2) V-1 s(-1). AnAl(0.83)In(0.17)N barrier HEMT device with 1 mu m gate length provides a current density of 1.0 A mm(-1) at V-GS = 0 V and an extrinsic transconductance of 242 mS mm(-1), which are remarkably improved compared to that of a conventional Al0.3Ga0.7N barrier HEMT. To investigate the thermal stability of the HEMT epi-structures, post-growth annealing experiments up to 800 degrees C have been applied to Al0.83In0.17N and Al0.3Ga0.7N barrier heterostructures. As expected, the electrical properties of an Al0.83In0.17N barrier HEMT structure showed less stability than that of an Al0.3Ga0.7N barrier HEMT to the thermal annealing. The structural properties of Al0.83In0.17N/GaN also showed more evidence for decomposition than that of the Al0.3Ga0.7N/GaN structure after 800 degrees C post-annealing

Utilization of Colemanite waste in Concrete Design

Waste material is formed in enormous quantities during the beneficiation of raw ore. These wastes can cause both economic loss and environmental pollution. Thus, in this study, the effect of CW obtained from Eti Mine Establishments Kütahya-Emet Boron Plants on the compressive strength and cylinder splitting tensile strength of concrete and its USAbility as a concrete admixture is investigated. The results found show that utilization of Colemanite Waste is possible when it is used as additive in concrete

An Update of Weed Flora of Vıneyards ın Northwestern Turkey

The weed flora of vineyards in northwestern Turkey was determined in a survey carried out in 93 vineyards. Total of 68 species 53 dicotyledonous and 11 monocotyledonous belonging to 32 families were identified in grape growing areas. The majority of weed species were annual species with different vegetation periods. The dominant weed species in the region were Capsella bursa pastoris, Convolvulus arvensis, Senecio vulgaris, Stellaria media, Sorghum halepense, Euphorbia helioscopia. Meanwhile frequent families were Poaceae, Asteraceae, Brassicaceae, Fabaceae, Geraniaceae, Lamiaceae, Polygonaceae and Euphorbiaceae

A monoclonal antibody against DNA binding helix of p53 protein

Three monoclonal antibodies (Mabs) were generated against p53 DNA-binding core domain. When tested by immunoprecipitation, Western blot and immunofluorescence techniques, Mab 9E4, as well as 7D3 and 6B10 reacted with both wild-type and various mutant p53 proteins. The epitopes recognized by Mabs 7D3, 9E4 and 6B10 were located respectively within the amino acid residues 211-220, 281-290 and 291-300 of human p53 protein. The epitope recognized by 9E4 Mab coincides with helix 2, also called p53 DNA binding helix, which allows the direct contact of the protein with its target DNA sequences. This antibody may be useful to study transcription-dependent and transcription-independent activities of wild-type and mutant p53 proteins

Nanofiber-enhanced lightweight composite textiles for acoustic applications

This paper proposes lightweight textile acoustic structure, wherein electrospun polyacrylonitrile-based nanofibers enhance sound absorption properties with no weight and thickness penalty. Polyacrylonitrile nanofibers with diameter of 110 ± 7 nm were electrospun on spacer-knitted fabrics by varying deposition amount and surface coating arrangement. Proposed novel approach eliminated additional processing steps such as handling and post-lamination and provided easy scalability of nanofibers at macro-scale. The results showed that the sound absorption of nano-enhanced specimens was improved drastically when deposited amount of nanofibers or its effective surface area increased. Sound propagation paths in different configurations were interpreted from sound absorption and air permeability measurements. The sound absorption coefficient values up to 0.7 are achieved in the low and medium frequency ranges with no weight and thickness penalty by tuning deposition amount and surface coating arrangement

Genome-Wide Transcriptional Reorganization Associated with Senescence-to-Immortality Switch during Human Hepatocellular Carcinogenesis

Cataloged from PDF version of article.Senescence is a permanent proliferation arrest in response to cell stress such as DNA damage. It contributes strongly to tissue aging and serves as a major barrier against tumor development. Most tumor cells are believed to bypass the senescence barrier (become "immortal") by inactivating growth control genes such as TP53 and CDKN2A. They also reactivate telomerase reverse transcriptase. Senescence-to-immortality transition is accompanied by major phenotypic and biochemical changes mediated by genome-wide transcriptional modifications. This appears to happen during hepatocellular carcinoma (HCC) development in patients with liver cirrhosis, however, the accompanying transcriptional changes are virtually unknown. We investigated genome-wide transcriptional changes related to the senescence-to-immortality switch during hepatocellular carcinogenesis. Initially, we performed transcriptome analysis of senescent and immortal clones of Huh7 HCC cell line, and identified genes with significant differential expression to establish a senescence-related gene list. Through the analysis of senescence-related gene expression in different liver tissues we showed that cirrhosis and HCC display expression patterns compatible with senescent and immortal phenotypes, respectively; dysplasia being a transitional state. Gene set enrichment analysis revealed that cirrhosis/senescence-associated genes were preferentially expressed in non-tumor tissues, less malignant tumors, and differentiated or senescent cells. In contrast, HCC/immortality genes were up-regulated in tumor tissues, or more malignant tumors and progenitor cells. In HCC tumors and immortal cells genes involved in DNA repair, cell cycle, telomere extension and branched chain amino acid metabolism were up-regulated, whereas genes involved in cell signaling, as well as in drug, lipid, retinoid and glycolytic metabolism were down-regulated. Based on these distinctive gene expression features we developed a 15-gene hepatocellular immortality signature test that discriminated HCC from cirrhosis with high accuracy. Our findings demonstrate that senescence bypass plays a central role in hepatocellular carcinogenesis engendering systematic changes in the transcription of genes regulating DNA repair, proliferation, differentiation and metabolism

Double subband occupation of the two-dimensional electron gas in InxAl1− xN/AlN/ GaN/AlN heterostructures with a low indium content (0.064≤x≤0.140) barrier

Cataloged from PDF version of article.We present a carrier transport study on low indium content (0.064≤x≤0.140) InxAl1−xN/AlN/GaN/AlN heterostructures. Experimental Hall data were carried out as a function of temperature (33–300 K) and a magnetic field (0–1.4 T). A two-dimensional electron gas (2DEG) with single or double subbands and a twodimensional hole gas were extracted after implementing quantitative mobility spectrum analysis on the magnetic field dependent Hall data. The mobility of the lowest subband of 2DEG was found to be lower than the mobility of the second subband. This behavior is explained by way of interface related scattering mechanisms, and the results are supported with a one-dimensional self-consistent solution of non-linear Schrödinger–Poisson equations