ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Fluid Mechanics and Thermodynamics  (3)
  • Flower-specific cDNAs  (2)
  • 1
    Electronic Resource
    Electronic Resource
    The proteins encoded by two tapetum-specific transcripts, Satap35 and Satap44, from Sinipis alba L. are localized in the exine cell wall layer of developing microspores (1994)
    Springer
    Planta 192 (1994), S. 221-231 
    Details
    ISSN: 1432-2048
    Keywords: Exine ; Flower-specific cDNAs ; Maltose-binding protein fusions ; Peritapetal membrane ; Pro-Ubisch bodies ; Signal sequence ; Sinapis ; Tapetum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By differential screening of a copy DNA (cDNA) library from flowering Sinapis alba L. apices against cDNAs from vegetative apices, two cDNA clones were isolated representing transcripts that are expressed transiently at an early stage of tapetum development. The Satap35 cDNA encodes a polypeptide with a predicted molecular weight of 12.7 kDa and an isoelectric point of 10.4. The Satap44 cDNA codes for a putative 12.4-kDa polypeptide with an isoelectric point of 7.5. The deduced amino-acid sequences display 76% sequence identity and contain an N-terminal stretch of hydrophobic amino acids which has characteristics of secretory signal sequences. In-vitro transcription of the cDNAs and translation of the resulting RNAs in the presence of canine pancreatic microsomes demonstrates that the two proteins are translocated into the microsomes and that the putative preproteins are proteolytically processed to the mature forms. By immunoelectron microscopy the SaTAP35 and SaTAP44 proteins were detected at the developing peritapetal membrane between the tapetal cytoplasm and the adjacent middle layer of the anther wall. Furthermore, labelling was observed within the locule in association with globules resembling pro-Ubisch bodies which appeared at the tetrad stage. During the early vacuolate stage of microspore development the young exine was strongly labelled. The exine and the peritapetal membrane both are composed of sporopollenin, and the pro-Ubisch bodies are thought to contain sporopollenin precursors. Thus, SaTAP35 and SaTAP44 might be involved in sporopollenin formation and/or deposition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194456
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The proteins encoded by two tapetum-specific transcripts,Satap35 andSatap44, fromSinapis alba L. are localized in the exine cell wall layer of developing microspores (1994)
    Springer
    Planta 192 (1994), S. 221-231 
    Details
    ISSN: 1432-2048
    Keywords: Exine ; Flower-specific cDNAs ; Maltose-binding protein fusions ; Peritapetal membrane ; Pro-Ubisch bodies ; Signal sequence ; Sinapis ; Tapetum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By differential screening of a copy DNA (cDNA) library from floweringSinapis alba L. apices against cDNAs from vegetative apices, two cDNA clones were isolated representing transcripts that are expressed transiently at an early stage of tapetum development. TheSatap35 cDNA encodes a polypeptide with a predicted molecular weight of 12.7 kDa and an isoelectric point of 10.4. TheSatap44 cDNA codes for a putative 12.4-kDa polypeptide with an isoelectric point of 7.5. The deduced amino-acid sequences display 76% sequence identity and contain an N-terminal stretch of hydrophobic amino acids which has characteristics of secretory signal sequences. In-vitro transcription of the cDNAs and translation of the resulting RNAs in the presence of canine pancreatic microsomes demonstrates that the two proteins are translocated into the microsomes and that the putative preproteins are proteolytically processed to the mature forms. By immunoelectron microscopy theSaTAP35 andSaTAP44 proteins were detected at the developing peritapetal membrane between the tapetal cytoplasm and the adjacent middle layer of the anther wall. Furthermore, labelling was observed within the locule in association with globules resembling pro-Ubisch bodies which appeared at the tetrad stage. During the early vacuolate stage of microspore development the young exine was strongly labelled. The exine and the peritapetal membrane both are composed of sporopollenin, and the pro-Ubisch bodies are thought to contain sporopollenin precursors. Thus,SaTAP35 andSaTAP44 might be involved in sporopollenin formation and/or deposition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01089038
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    facet.materialart.
    Unknown
    Study of Convective Flow Effects in Endwall Casing Treatments in Transonic Compressor Rotors (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The unsteady convective flow effects in a transonic compressor rotor with a circumferential-groove casing treatment are investigated in this paper. Experimental results show that the circumferential-groove casing treatment increases the compressor stall margin by almost 50% for the current transonic compressor rotor. Steady flow simulation of the current casing treatment, however, yields only a 15% gain in stall margin. The flow field at near-stall operation is highly unsteady due to several self-induced flow phenomena. These include shock oscillation, vortex shedding at the trailing edge, and interaction between the passage shock and the tip clearance vortex. The primary focus of the current investigation is to assess the effects of flow unsteadiness and unsteady flow convection on the circumferential-groove casing treatment. Unsteady Reynolds-averaged Navier-Stokes (URANS) and Large Eddy Simulation (LES) techniques were applied in addition to steady Reynolds-averaged Navier-Stokes (RANS) to simulate the flow field at near-stall operation and to determine changes in stall margin. The current investigation reveals that unsteady flow effects are as important as steady flow effects on the performance of the circumferential grooves casing treatment in extending the stall margin of the current transonic compressor rotor. The primary unsteady flow mechanism is unsteady flow injection from the grooves into the main flow near the casing. Flows moving into and out of the grooves are caused due to local pressure difference near the grooves. As the pressure field becomes transient due to self-induced flow oscillation, flow injection from the grooves also becomes unsteady. The unsteady flow simulation shows that this unsteady flow injection from the grooves is substantial and contributes significantly to extending the compressor stall margin. Unsteady flows into and out of the grooves have as large a role as steady flows in the circumferential grooves. While the circumferential-groove casing treatment seems to be a steady flow device, unsteady flow effects should be included to accurately assess its performance as the flow is transient at near-stall operation.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: GT2012-68411 , E-18398 , ASME Turbo Expo; Jun 11, 2012 - Jun 15, 2012; Copenhagen; Denmark
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    Aerodynamic Inner Workings of Circumferential Grooves in a Transonic Axial Compressor (2007)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The current paper reports on investigations of the fundamental flow mechanisms of circumferential grooves applied to a transonic axial compressor. Experimental results show that the compressor stall margin is significantly improved with the current set of circumferential grooves. The primary focus of the current investigation is to advance understanding of basic flow mechanics behind the observed improvement of stall margin. Experimental data and numerical simulations of a circumferential groove were analyzed in detail to unlock the inner workings of the circumferential grooves in the current transonic compressor rotor. A short length scale stall inception occurs when a large flow blockage is built on the pressure side of the blade near the leading edge and incoming flow spills over to the adjacent blade passage due to this blockage. The current study reveals that a large portion of this blockage is created by the tip clearance flow originating from 20% to 50% chord of the blade from the leading edge. Tip clearance flows originating from the leading edge up to 20% chord form a tip clearance core vortex and this tip clearance core vortex travels radially inward. The tip clearance flows originating from 20% to 50% chord travels over this tip clearance core vortex and reaches to the pressure side. This part of tip clearance flow is of low momentum as it is coming from the casing boundary layer and the blade suction surface boundary layer. The circumferential grooves disturb this part of the tip clearance flow close to the casing. Consequently the buildup of the induced vortex and the blockage near the pressure side of the passage is reduced. This is the main mechanism of the circumferential grooves that delays the formation of blockage near the pressure side of the passage and delays the onset of short length scale stall inception. The primary effect of the circumferential grooves is preventing local blockage near the pressure side of the blade leading edge that directly determines flow spillage around the leading edge. The circumferential grooves do not necessarily reduce the over all blockage built up at the rotor tip section.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: IGTC2007-ABS-55 , 2007 International Gas Turbine Congress (IGTC); Dec 01, 2007; Tokyo; Japan
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    Investigation of Unsteady Flow Behavior in Transonic Compressor Rotors with LES and PIV Measurements (2009)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: In the present study, unsteady flow behavior in a modern transonic axial compressor rotor is studied in detail with large eddy simulation (LES) and particle image velocimetry (PIV). The main purpose of the study is to advance the current understanding of the flow field near the blade tip in an axial transonic compressor rotor near the stall and peak-efficiency conditions. Flow interaction between the tip leakage vortex and the passage shock is inherently unsteady in a transonic compressor. Casing-mounted unsteady pressure transducers have been widely applied to investigate steady and unsteady flow behavior near the casing. Although many aspects of flow have been revealed, flow structures below the casing cannot be studied with casing-mounted pressure transducers. In the present study, unsteady velocity fields are measured with a PIV system and the measured unsteady flow fields are compared with LES simulations. The currently applied PIV measurements indicate that the flow near the tip region is not steady even at the design condition. This self-induced unsteadiness increases significantly as the compressor rotor operates near the stall condition. Measured data from PIV show that the tip clearance vortex oscillates substantially near stall. The calculated unsteady characteristics of the flow from LES agree well with the PIV measurements. Calculated unsteady flow fields show that the formation of the tip clearance vortex is intermittent and the concept of vortex breakdown from steady flow analysis does not seem to apply in the current flow field. Fluid with low momentum near the pressure side of the blade close to the leading edge periodically spills over into the adjacent blade passage. The present study indicates that stall inception is heavily dependent on unsteady behavior of the flow field near the leading edge of the blade tip section for the present transonic compressor rotor.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: ISABE-2009-02 , E-17156-P , 2009 ISABE Conference; Sep 07, 2009 - Sep 11, 2009; Montreal; Canada
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...