scholarly journals Image Compression Using Adaptive Variable Degree Variable Segment Length Chebyshev Polynomials

2005 ◽  
pp. 1196-1207
Author(s):  
I. A. Al-Jarwan ◽  
M. J. Zemerly
Keyword(s):  
Image Compression ◽  
Chebyshev Polynomials ◽  
Segment Length ◽  
Variable Degree ◽  
Variable Segment ◽  
Degree Variable

Enhancement of Temperature Blending in Convective Heat Transfer by Motionless Inserts With Variable Segment Length

2010 ◽  
Vol 2 (3) ◽  
Author(s):  
Ramin K. Rahmani ◽  
Anahita Ayasoufi ◽  
Emad Y. Tanbour ◽  
Hosein Molavi
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Convective Heat Transfer ◽  
Turbulent Flows ◽  
Convective Heat ◽  
Segment Length ◽  
Width Ratio ◽  
Enhance Heat Transfer ◽  
Variable Segment ◽  
The Impact

Stationary spiral inserts can effectively enhance heat transfer and temperature blending in the heat convection systems. In this paper, the impact of the segment length on the performance of a stationary insert is studied for flow Re numbers from ∼80 to ∼7900 through numerical simulation of heat transfer in streams of cold and hot gases flowing across it. The segment length to width ratio is from 1.11 to 2.33. The temperature of the studied gas is from 300 K to 1300 K. It is shown that the insert with variable segment length is more effective in temperature blending for two compressible streams compared with an insert with constant segment length, especially for low-Re-number turbulent flows.

Enhancement of Temperature Blending in Convective Heat Transfer by Motionless Inserts With Variable Segment Length

2009 ◽  
Author(s):  
Emad Y. Tanbour ◽  
Ramin K. Rahmani
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Convection Heat Transfer ◽  
Segment Length ◽  
Flowing Fluid ◽  
Thermal Fields ◽  
Variable Segment ◽  
The Subject ◽  
The Impact ◽  
Stationary Heat Transfer

Enhancement of natural and forced convection heat transfer has been the subject of numerous academic and industrial studies. Stationary inserts can be efficiently employed as enhancement devices for heat transfer and temperature blending in the heat convection systems. Generally, a stationary heat transfer enhancement insert consists of a number of equal (or similar) motionless segments, placed inside of a pipe in order to control flowing fluid streams. An ideal insert, for temperature blending in compressible flow applications, provides a smaller standard deviation of temperature with minimized pressure drop and required space. The ratio of temperature uniformity to the pressure drop can be used to determine the efficiency of an insert design. It is possible to use different segment lengths for a given insert design to maximize this ratio. Numerical simulation for heat transfer in turbulent flow is employed to simulate the flow and thermal fields for streams of cold and hot gases flowing across stationary inserts with variable segment length and to study the impact of the segment length on the performance of the insert. It is shown that the insert with variable segment length is more effective in temperature blending for two compressible streams.

Carotid endarterectomy in patients with foetal-type posterior circle of Willis: Is there an indication for local anaesthesia?

VASA ◽  
2011 ◽  
Vol 40 (5) ◽  
pp. 404-407
Author(s):  
Maras ◽  
Tzormpatzoglou ◽  
Papas ◽  
Papanas ◽  
Kotsikoris ◽  
...  
Keyword(s):  
Carotid Endarterectomy ◽  
Local Anaesthesia ◽  
Anatomical Variation ◽  
Anatomical Variations ◽  
Circle Of Willis ◽  
Variable Degree ◽  
Operative Complications ◽  
The Right ◽  
Ica Stenosis ◽  
Symptomatic Stenosis

Foetal-type posterior circle of Willis is a common anatomical variation with a variable degree of vessel asymmetry. In patients with this abnormality, carotid endarterectomy (CEA) may create cerebral hypo-perfusion intraoperatively, and this may be underestimated under general anaesthesia. There is currently no evidence that anatomical variations in the circle of Willis represent an independent risk factor for stroke. Moreover, there is a paucity of data on treating patients with such anatomical variations and co-existing ICA stenosis. We present a case of CEA under local anaesthesia (LA) in a 52-year-old female patient with symptomatic stenosis of the right ICA and coexistent foetal-type posterior circle of Willis. There were no post-operative complications and she was discharged free from symptoms. She was seen again 3 months later and was free from complications. This case higlights that LA should be strongly considered to enable better intra-operative neurological monitoring in the event of foetal-type posterior circle of Willis.

Abnormal Structure of von Willebrand Factor in Myeloproliferative Syndrome Is Associated to Either Thrombotic or Bleeding Diathesis

1987 ◽  
Vol 58 (02) ◽  
pp. 753-757 ◽  
Author(s):  
M F López-Fernández ◽  
C López-Berges ◽  
R Martín ◽  
A Pardo ◽  
F J Ramos ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Proteinase Inhibitors ◽  
Relative Proportion ◽  
Variable Degree ◽  
Bleeding Diathesis ◽  
Myeloproliferative Syndrome ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryThe multimeric and subunit patterns of plasma von Willebrand factor (vWF) were analyzed in eight patients with myeloproliferative syndrome (MS) in order to investigate the possible existence of heterogeneity in the “in vivo” proteolytic cleavage of the protein, previously observed in this entity. Six patients lacked large vWF multimers, five of them having normal bleeding times (BT) and clinically documented episodes of thrombotic origin, whereas one patient had long BT and bleeding symptoms. Seven patients showed a relative increase in the 176 kDa subunit fragment while the 189 kDa polypeptide was increased in only one. In addition, another patient (and prior to any therapy) showed the presence of a new fragment of approximately 95 kDa which disappeared after Busulfan therapy. The collection of blood from these patients with proteinase inhibitors did not correct the abnormalities.The infusion of DDAVP to two patients with abnormal vWF was accompanied by: the appearance of larger vWF multimers which disappeared rapidly from plasma; an increase in the relative proportion of the satellite bands of each multimer and a further increase of the 176 kDa fragment. These data point to some heterogeneity in the vWF abnormality present in MS which may be related in part to a variable degree of proteolysis of vWF occurring “in vivo” rather than “in vitro”, and which may be associated to either a thrombotic or a bleeding diathesis. They also suggest that despite the presence of abnormal, already proteolyzed vWF, DDAVP-enhanced proteolysis occurs in MS to a similar extent to what is described in normal individuals.

Image Compression Using Vector Quantization with Variable Block Size Division

2010 ◽  
Vol 130 (8) ◽  
pp. 1431-1439 ◽  
Author(s):  
Hiroki Matsumoto ◽  
Fumito Kichikawa ◽  
Kazuya Sasazaki ◽  
Junji Maeda ◽  
Yukinori Suzuki
Keyword(s):  
Image Compression ◽  
Vector Quantization ◽  
Block Size ◽  
Variable Block
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