The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
G N Tiwari - One of the best experts on this subject based on the ideXlab platform.
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evaluation of convective heat transfer coefficient in crop drying under open sun drying conditions
Energy Conversion and Management, 2001Co-Authors: S I Anwar, G N TiwariAbstract:Abstract In this paper, an attempt has been made to evaluate the convective heat transfer coefficient operating in crop drying in open sun drying conditions (natural convection). Values of the constants, C and n were obtained by linear regression analysis from Experimental data obtained for six crops, namely green chillies, green peas, Kabuli chana, onion, potato and cauliflower. Analysis was also performed for Kabuli chana under natural cooling conditions. Based on the values of C and n convective heat transfer coefficients for these crops were determined. The Experimental Error in terms of percent uncertainty was also calculated.
S I Anwar - One of the best experts on this subject based on the ideXlab platform.
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evaluation of convective heat transfer coefficient in crop drying under open sun drying conditions
Energy Conversion and Management, 2001Co-Authors: S I Anwar, G N TiwariAbstract:Abstract In this paper, an attempt has been made to evaluate the convective heat transfer coefficient operating in crop drying in open sun drying conditions (natural convection). Values of the constants, C and n were obtained by linear regression analysis from Experimental data obtained for six crops, namely green chillies, green peas, Kabuli chana, onion, potato and cauliflower. Analysis was also performed for Kabuli chana under natural cooling conditions. Based on the values of C and n convective heat transfer coefficients for these crops were determined. The Experimental Error in terms of percent uncertainty was also calculated.
M. A. J. Botje - One of the best experts on this subject based on the ideXlab platform.
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qcd fits to zeus and fixed target structure function data
arXiv: High Energy Physics - Phenomenology, 1997Co-Authors: M. A. J. BotjeAbstract:Preliminary results are presented on the gluon density obtained from a QCD analysis of ZEUS and NMC F2 structure function data. Also given is an estimate of the Experimental Error on the positron-proton NC Born cross-section at large x and Q2.
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QCD fits to ZEUS and fixed target structure function data
1997Co-Authors: M. A. J. BotjeAbstract:Preliminary results are presented on the gluon density at low x obtained from a QCD analysis of ZEUS 1994 F2 structure function data combined with those from NMC. Also given are estimates of the Experimental Error on the e+p NC Born cross section at large x and Q2. This estimate is obtained from propagation of the statistical and systematic Errors on fixed target structure functions.
C R Wirtz - One of the best experts on this subject based on the ideXlab platform.
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comparative study of application accuracy of two frameless neuronavigation systems Experimental Error assessment quantifying registration methods and clinically influencing factors
Neurosurgical Review, 2011Co-Authors: Dimitrios Paraskevopoulos, Andreas Unterberg, Roland Metzner, Jens Dreyhaupt, Georg Eggers, C R WirtzAbstract:This study aimed at comparing the accuracy of two commercial neuronavigation systems. Error assessment and quantification of clinical factors and surface registration, often resulting in decreased accuracy, were intended. Active (Stryker Navigation) and passive (VectorVision Sky, BrainLAB) neuronavigation systems were tested with an anthropomorphic phantom with a deformable layer, simulating skin and soft tissue. True coordinates measured by computer numerical control were compared with coordinates on image data and during navigation, to calculate software and system accuracy respectively. Comparison of image and navigation coordinates was used to evaluate navigation accuracy. Both systems achieved an overall accuracy of <1.5 mm. Stryker achieved better software accuracy, whereas BrainLAB better system and navigation accuracy. Factors with conspicuous influence (P < 0.01) were imaging, instrument replacement, sterile cover drape and geometry of instruments. Precision data indicated by the systems did not reflect measured accuracy in general. Surface matching resulted in no improvement of accuracy, confirming former studies. Laser registration showed no differences compared to conventional pointers. Differences between the two systems were limited. Surface registration may improve inaccurate point-based registrations but does not in general affect overall accuracy. Accuracy feedback by the systems does not always match with true target accuracy and requires critical evaluation from the surgeon.
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comparative study of application accuracy of two frameless neuronavigation systems Experimental Error assessment quantifying registration methods and clinically influencing factors
Neurosurgical Review, 2011Co-Authors: Dimitrios Paraskevopoulos, Andreas Unterberg, Roland Metzner, Jens Dreyhaupt, Georg Eggers, C R WirtzAbstract:This study aimed at comparing the accuracy of two commercial neuronavigation systems. Error assessment and quantification of clinical factors and surface registration, often resulting in decreased accuracy, were intended. Active (Stryker Navigation) and passive (VectorVision Sky, BrainLAB) neuronavigation systems were tested with an anthropomorphic phantom with a deformable layer, simulating skin and soft tissue. True coordinates measured by computer numerical control were compared with coordinates on image data and during navigation, to calculate software and system accuracy respectively. Comparison of image and navigation coordinates was used to evaluate navigation accuracy. Both systems achieved an overall accuracy of <1.5 mm. Stryker achieved better software accuracy, whereas BrainLAB better system and navigation accuracy. Factors with conspicuous influence (P < 0.01) were imaging, instrument replacement, sterile cover drape and geometry of instruments. Precision data indicated by the systems did not reflect measured accuracy in general. Surface matching resulted in no improvement of accuracy, confirming former studies. Laser registration showed no differences compared to conventional pointers. Differences between the two systems were limited. Surface registration may improve inaccurate point-based registrations but does not in general affect overall accuracy. Accuracy feedback by the systems does not always match with true target accuracy and requires critical evaluation from the surgeon.
John A Tainer - One of the best experts on this subject based on the ideXlab platform.
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the r factor gap in macromolecular crystallography an untapped potential for insights on accurate structures
FEBS Journal, 2014Co-Authors: James M Holton, Scott Classen, Kenneth A Frankel, John A TainerAbstract:In macromolecular crystallography, the agreement between observed and predicted structure factors (Rcryst and Rfree) is seldom better than 20%. This is much larger than the estimate of Experimental Error (Rmerge). The difference between Rcryst and Rmerge is the R-factor gap. There is no such gap in small-molecule crystallography, for which calculated structure factors are generally considered more accurate than the Experimental measurements. Perhaps the true noise level of macromolecular data is higher than expected? Or is the gap caused by inaccurate phases that trap refined models in local minima? By generating simulated diffraction patterns using the program MLFSOM, and including every conceivable source of Experimental Error, we show that neither is the case. Processing our simulated data yielded values that were indistinguishable from those of real data for all crystallographic statistics except the final Rcryst and Rfree. These values decreased to 3.8% and 5.5% for simulated data, suggesting that the reason for high R-factors in macromolecular crystallography is neither Experimental Error nor phase bias, but rather an underlying inadequacy in the models used to explain our observations. The present inability to accurately represent the entire macromolecule with both its flexibility and its protein-solvent interface may be improved by synergies between small-angle X-ray scattering, computational chemistry and crystallography. The exciting implication of our finding is that macromolecular data contain substantial hidden and untapped potential to resolve ambiguities in the true nature of the nanoscale, a task that the second century of crystallography promises to fulfill. Database Coordinates and structure factors for the real data have been submitted to the Protein Data Bank under accession 4tws.
