The Full-Scale Viscous Drag of Actual Ship Surfaces and the Effect of Quality of Roughness on Predicted Power

1987 ◽  
Vol 31 (03) ◽  
pp. 189-206
Author(s):  
Christopher Grigson
Keyword(s):  
Surface Quality ◽  
Data Bank ◽  
Full Scale ◽  
Viscous Drag ◽  
Drag Coefficients ◽  
Predicting Performance ◽  
Different Shapes ◽  
Coated Surfaces

The hydrodynamic roughness functions of hull surfaces are surveyed. Δu+ is given for many different coated surfaces; all the surfaces have different topographies and all have roughness functions of different shapes which reveal that the quality of the roughness is as important as height in the generation of drag. The variety of these functions demonstrates that the viscous drag cannot be predicted without the use of the actual Au+ of the surface of interest. The planar drag coefficients of some of the hull surfaces are given as curves of CFR(Rn) and of ΔO(Rn). The behavior of ΔC with speed is compared with that deduced from careful trials, and is fully compatible with it. It is not compatible, however, with that of the ITTC formulae for AC, and the scientific foundations of the formulae are studied and found unsatisfactory. The influence of surface quality, hitherto not taken into account in predicting performance, could easily explain the relatively large errors in the statistics of predicted trial power. Shipbuilders need to measure the functions ΔU+ of their new hull surfaces and to acquire a data bank connecting their methods of finishing their hulls with Δu+.

Indicators of Sustainable Development of the Province of Warmia and Mazury in the Environmental Aspect

2016 ◽  
Vol 11 (3) ◽  
pp. 299-309
Author(s):  
Mirosława Witkowska-Dąbrowska
Keyword(s):  
Quality Of Life ◽  
Sustainable Development ◽  
Data Bank ◽  
Local Data ◽  
Indicator Method ◽  
Environmental Aspect ◽  
The Sustainable Development ◽  
Assessment Indicator ◽  
Area Unit

The purpose of this study has been to identify the degree of sustainability in the development of the Province of Warmia and Mazury. The theoretical and empirical investigations were conducted between 2003-2014 based on data from the Local Data Bank. Using a comparative indicator method, 20 indicators were developed, with different directions of preference. The evaluation involves the concept of uniform preference, hence the higher the assessment indicator, the better the situation in the evaluated area unit. Our studies on the sustainable development of the Province of Warmia and Mazury suggest that the indicators measuring the environmental dimension and consequently the quality of life of the residents (in this aspect) score higher than the country's average values. It is also optimistic that some progress, however small, can be seen in this area based on the analyzed dynamics of changes.

Schwingungsüberlagertes Axialformen/Superimposed Oscillated Axial Forming

2020 ◽  
Vol 110 (11-12) ◽  
pp. 838-843
Author(s):  
Philipp Müller ◽  
Bernd-Arno Behrens ◽  
Sven Hübner ◽  
Hendrik Vogt ◽  
Daniel Rosenbusch ◽  
...  
Keyword(s):  
Surface Quality ◽  
Economic Importance ◽  
Combined Effect ◽  
Wird Eine ◽  
Forming Force ◽  
Forming Process ◽  
Forming Technology ◽  
Great Economic Importance ◽  
Gear Geometry

Techniken zur Steigerung der Formgebungsgrenzen in der Umformtechnik sind von hoher wirtschaftlicher Bedeutung. In dieser Arbeit wird eine Schwingungsüberlagerung im Krafthauptfluss eines Axialformprozesses zur Ausprägung einer Verzahnungsgeometrie untersucht. Die Auswirkungen der Schwingung auf die erzielbare Ausfüllung der Zahnkavitäten werden analysiert sowie die Parameter Schmierung und Oberflächengüte der Halbzeuge in ihrer kombinierten Wirkung untersucht. Es konnte eine Reduzierung der mittleren Umformkraft sowie eine Erhöhung der Formfüllung festgestellt werden. Techniques for extending the production limits in forming technology are of great economic importance. In this research, a superimposed oscillation in the main force flow of an axial forming process to form an axial gear geometry is investigated. The effects of the superimposed oscillation on the achievable form-filling of the tooth cavities are analyzed and the parameters lubrication and surface quality of the semi-finished products are investigated in their combined effect. A reduction of the averaged forming force as well as an increase of the form-filling could be achieved.

Automatic buffer capacity based sensor for effluent quality monitoring

1996 ◽  
Vol 33 (1) ◽  
pp. 81-87
Author(s):  
L. Van Vooren ◽  
P. Willems ◽  
J. P. Ottoy ◽  
G. C. Vansteenkiste ◽  
W. Verstraete
Keyword(s):  
Wastewater Treatment ◽  
Buffer Capacity ◽  
Wastewater Treatment Plants ◽  
Data Interpretation ◽  
Full Scale ◽  
Quality Monitoring ◽  
Effluent Quality ◽  
Capacity Curves ◽  
On Line

The use of an automatic on-line titration unit for monitoring the effluent quality of wastewater plants is presented. Buffer capacity curves of different effluent types were studied and validation results are presented for both domestic and industrial full-scale wastewater treatment plants. Ammonium and ortho-phosphate monitoring of the effluent were established by using a simple titration device, connected to a data-interpretation unit. The use of this sensor as the activator of an effluent quality proportional sampler is discussed.

Reuse of Sludge from Pulp and Paper Industry Pilot and Full Scale Applications

1993 ◽  
Vol 28 (2) ◽  
pp. 17-26 ◽  
Author(s):  
V. Eroǧlu ◽  
A. M. Saatçi
Keyword(s):  
Economic Analysis ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Full Scale ◽  
Primary Sludge ◽  
Recent Advances ◽  
Made In

Recent advances made in the reuse of pulp and paper industry sludges in hardboard production are explained. Data obtained from pilot and full-scale plants using primary sludge of a pulp and paper industry as an additive in the production of hardboard is presented. An economic analysis of the reuse of pulp and paper primary sludge in hardboard manufacturing is given. The quality of the hardboard produced is tested and compared with the qualities of the hardboard produced by the same plant before the addition of primary sludge. The hardboard with primary sludge additive has been used in Turkey for about a year in the manufacturing of office and home furniture. The results are very satisfactory when the primary sludge is used at 1/4 ratio.

scholarly journals Cryo-EM model validation recommendations based on outcomes of the 2019 EMDataResource challenge

2021 ◽  
Vol 18 (2) ◽  
pp. 156-164 ◽  
Author(s):  
Catherine L. Lawson ◽  
Andriy Kryshtafovych ◽  
Paul D. Adams ◽  
Pavel V. Afonine ◽  
Matthew L. Baker ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structure Data ◽  
Model Evaluation ◽  
Data Bank ◽  
High Accuracy ◽  
Atomic Resolution ◽  
Software Developers ◽  
Data Archives ◽  
Modeling Software

AbstractThis paper describes outcomes of the 2019 Cryo-EM Model Challenge. The goals were to (1) assess the quality of models that can be produced from cryogenic electron microscopy (cryo-EM) maps using current modeling software, (2) evaluate reproducibility of modeling results from different software developers and users and (3) compare performance of current metrics used for model evaluation, particularly Fit-to-Map metrics, with focus on near-atomic resolution. Our findings demonstrate the relatively high accuracy and reproducibility of cryo-EM models derived by 13 participating teams from four benchmark maps, including three forming a resolution series (1.8 to 3.1 Å). The results permit specific recommendations to be made about validating near-atomic cryo-EM structures both in the context of individual experiments and structure data archives such as the Protein Data Bank. We recommend the adoption of multiple scoring parameters to provide full and objective annotation and assessment of the model, reflective of the observed cryo-EM map density.

scholarly journals Face Grinding Surface Quality of High Volume Fraction SiCp/Al Composite Materials

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Xu Zhao ◽  
Yadong Gong ◽  
Guiqiang Liang ◽  
Ming Cai ◽  
Bing Han
Keyword(s):  
Friction Coefficient ◽  
Surface Morphology ◽  
Surface Quality ◽  
Volume Fraction ◽  
High Volume ◽  
Spindle Speed ◽  
High Volume Fraction ◽  
Machining Parameters ◽  
Al Composite

AbstractThe existing research on SiCp/Al composite machining mainly focuses on the machining parameters or surface morphology. However, the surface quality of SiCp/Al composites with a high volume fraction has not been extensively studied. In this study, 32 SiCp/Al specimens with a high volume fraction were prepared and their machining parameters measured. The surface quality of the specimens was then tested and the effect of the grinding parameters on the surface quality was analyzed. The grinding quality of the composite specimens was comprehensively analyzed taking the grinding force, friction coefficient, and roughness parameters as the evaluation standards. The best grinding parameters were obtained by analyzing the surface morphology. The results show that, a higher spindle speed should be chosen to obtain a better surface quality. The final surface quality is related to the friction coefficient, surface roughness, and fragmentation degree as well as the quantity and distribution of the defects. Lower feeding amount, lower grinding depth and appropriately higher spindle speed should be chosen to obtain better surface quality. Lower feeding amount, higher grinding depth and spindle speed should be chosen to balance grind efficiently and surface quality. This study proposes a systematic evaluation method, which can be used to guide the machining of SiCp/Al composites with a high volume fraction.

Simulation and Productive Practice of 60 Tons Huge Rectangular Ingot by Wind Cooling

2011 ◽  
Vol 233-235 ◽  
pp. 2714-2717
Author(s):  
Xin Gang Ai ◽  
Sheng Li Li ◽  
Dong Wei Zhang ◽  
Nan Lv ◽  
Jun Tao
Keyword(s):  
Mathematical Simulation ◽  
Surface Quality ◽  
Solidification Time ◽  
Special Method ◽  
Cooling Process ◽  
Heavy Plate ◽  
Simulation Results

Huge rectangular ingots becomes crying needs in the condition of lots of heavy plate mills more than 5m have been in operation. In this paper, a special method of wind cooling outside mould has been presented and applied to produce 60t rectangular ingot. Mathematical simulation results tell us that by wind cooling, the solidification time of the 60t ingot can be shortened by 67 minutes, internal soundness can be ensured. The wind cooling process can obviously improve microstructure and preventing skull patch by increasing the thickness of solidified shell. A 60 tons huge rectangular ingot is successfully produced by wind cooling, the surface quality of is very well and the internal soundness should be improved further.

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