scholarly journals Hydrodynamic testing of wind-assisted cargo ships using a cyber-physical empirical method

2021 ◽  
Author(s):  
Thomas Sauder ◽  
Sverre Anders Alterskjær
Keyword(s):  
Performance Indicators ◽  
Empirical Method ◽  
Hydrodynamic Resistance ◽  
Bulk Carrier ◽  
Important Conclusion ◽  
Free Running ◽  
Strong Winds ◽  
Wind Profiles ◽  
Accuracy And Repeatability ◽  
Hydrodynamic Testing

A novel empirical method to study wind-assisted cargo ships is presented. The physical ship model, including propulsion units, interacts in real-time with a numerical sail model during free-running tests. Loads from the (virtual) sails are applied on the physical model using a cable-driven robot. All loads components except heave are applied with high accuracy and repeatability. The method is described thoroughly, and applied to investigate the benefits of wind assistance on a 190m bulk-carrier, equipped with four rotor sails. Key performance indicators for wind assistance are established when sailing in steady wind profiles of various directions and velocities, and a propulsion analysis is performed. An important conclusion is that the increase of hydrodynamic resistance due to heel, leeway and rudder (that balance transverse sail loads) is rather limited for this ship, except when sailing close-hauled in strong winds. It is also demonstrated that experiments in a unsteady (virtual) wind environment can be successfully conducted. The effect of turbulence on the motions of this ship are found to be very limited. The conclusion discusses the other types of studies that can be enabled by this novel cyber-physical empirical method.

scholarly journals Snow Transport Over Mountain Crests

1980 ◽  
Vol 26 (94) ◽  
pp. 469-480 ◽  
Author(s):  
Paul M. B. Föhn
Keyword(s):  
Quantitative Relationship ◽  
Horizontal Wind ◽  
Snow Surface ◽  
Horizontal Wind Speed ◽  
Ridge Crest ◽  
Wind Speeds ◽  
Drift Flux ◽  
Strong Winds ◽  
Wind Profiles ◽  
Snow Transport

AbstractIn order to gain more insight into the mountain snow-transport mechanisms wind and drift flux measurements have been executed on a ridge crest (mainly during snow-storms). Horizontal wind-speed profiles, measured between 0.3 and 6 m above snow surface, show a hump-shaped course especially for strong winds. Theoretical approximations substantiate that the Bernoullian pressure decrease on the crest may be the main cause for this type of wind profile. Roughness parameters (Z0, u⋆) are determined with the aid of the wind profiles and compared with those reported in the literature. Corresponding drift density profiles coincide with steady-state drift theories as long as wind speeds are low (u1≤ 7-10 m s-1), at greater wind speeds snow plumes of 1 to 1.5 m thickness develop immediately above snow surface. Areal measurements on snow mass-balance differences between windward and lee slopes are used to approximate the total transport over the ridge crest and to derive a quantitative relationship between crest winds and drift-snow deposition on lee slopes.

Exercise of ownership rights and efficiency in state-owned enterprises: the case of Uruguay

2016 ◽  
Vol 14 (2) ◽  
pp. 150-165
Author(s):  
Ignacio Munyo ◽  
Pablo Regent
Keyword(s):  
Performance Indicators ◽  
Design Methodology ◽  
Natural Experiment ◽  
Negative Impact ◽  
Empirical Method ◽  
Content Type ◽  
Improve Efficiency ◽  
The Poor ◽  
Ownership Rights ◽  
Practical Implications

Purpose This paper aims to analyze the relevance of the exercise of ownership rights on the management of state-owned enterprises (SOEs). Design/methodology/approach The author exploited a “natural experiment” observed in Uruguay. The author developed an empirical method that to compare the results of SOEs between two five-year presidential terms with de facto differences with regard to the exercise of ownership rights. Findings The author found evidence suggesting that the poor exercise of ownership rights has a negative impact on the results of SOEs. Research limitations/implications The results of this study are based exclusively on the Uruguayan case and are limited to the comparison between two five-year terms. Practical implications A holding of SOEs that holds and exerts ownership rights emerges as a natural alternative to improve efficiency. Originality/value The exercise of ownership rights in SOEs has a significant impact on its performance indicators.

A Comparative Study of AODV and DSDV Routing Protocol of the Vehicle Ad Hoc Network Based on NS2

2013 ◽  
Vol 303-306 ◽  
pp. 1968-1973
Author(s):  
Yun Bai ◽  
Song Bo Ji ◽  
Yuan Xue
Keyword(s):  
Wireless Ad Hoc Networks ◽  
Routing Protocol ◽  
Performance Indicators ◽  
Ad Hoc ◽  
Mobile Nodes ◽  
Important Conclusion ◽  
Delay Performance ◽  
Vehicle Communication ◽  
Distance Vector ◽  
Hoc Networks

This document analyzes the wireless ad hoc networks used in vehicle communication. Using the NS2 software, the typical ad hoc on-demand distance vector routing (AODV) and destination-sequenced distance-vector (DSDV) routing protocol are simulated respectively with 25 mobile nodes and 11 mobile nodes. By reasoning on the simulation data, many performance indicators including the routing protocol throughput, jitter, packet loss rate and end-to-end delay performance are compared and analyzed. Final we have come to an important conclusion that AODV is better than DSDV protocol on a number of performance indicators.

scholarly journals Snow Transport Over Mountain Crests

1980 ◽  
Vol 26 (94) ◽  
pp. 469-480 ◽  
Author(s):  
Paul M. B. Föhn
Keyword(s):  
Quantitative Relationship ◽  
Horizontal Wind ◽  
Snow Surface ◽  
Horizontal Wind Speed ◽  
Ridge Crest ◽  
Wind Speeds ◽  
Drift Flux ◽  
Strong Winds ◽  
Wind Profiles ◽  
Snow Transport

AbstractIn order to gain more insight into the mountain snow-transport mechanisms wind and drift flux measurements have been executed on a ridge crest (mainly during snow-storms). Horizontal wind-speed profiles, measured between 0.3 and 6 m above snow surface, show a hump-shaped course especially for strong winds. Theoretical approximations substantiate that the Bernoullian pressure decrease on the crest may be the main cause for this type of wind profile. Roughness parameters (Z0, u⋆) are determined with the aid of the wind profiles and compared with those reported in the literature. Corresponding drift density profiles coincide with steady-state drift theories as long as wind speeds are low (u1≤ 7-10 m s-1), at greater wind speeds snow plumes of 1 to 1.5 m thickness develop immediately above snow surface. Areal measurements on snow mass-balance differences between windward and lee slopes are used to approximate the total transport over the ridge crest and to derive a quantitative relationship between crest winds and drift-snow deposition on lee slopes.

scholarly journals Assessment of apparent losses due to meter inaccuracy – a comparative approach

Water SA ◽  
2019 ◽  
Vol 45 (2 April) ◽  
Author(s):  
Mthokozisi Ncube ◽  
Akpofure Taigbenu
Keyword(s):  
Empirical Method ◽  
Alternative Methods ◽  
Comparative Approach ◽  
Great Promise ◽  
Water Losses ◽  
Average Value ◽  
Quality Water ◽  
Development And Validation ◽  
Water Meters ◽  
Accuracy And Repeatability

The empirical method for the determination of apparent water losses, using the assessment of consumption patterns and the laboratory testing of water meters, is compared against alternative methods of comparative billing and meter change analyses for one of the largest water utilities in South Africa. Using the empirical method, apparent losses are estimated to have an average value of 12% of the billed volume with a range from 9.4% to 14.6% that is dependent on meter size ratios. This overlaps with the estimates, of 8%−10% for a utility with direct feed good quality water but high meter age (> 10 yr) and low accuracy, currently proposed in some studies and used by industry. The estimate from the comparative billing analysis method is 14% and it is sensitive to how the data is processed and analysed. The meter change method yielded an estimate of 4.7% for only a subset of the data. Both results of the alternative methods are in line with previous studies, with the comparative billing analysis performing better, but requiring further refinement for better accuracy and repeatability. The empirical method remains the gold standard in assessing apparent water losses but is undoubtedly very laborious, expensive and out of reach of the budget of many utilities. The development and validation of alternative methodologies therefore holds great promise but these are substantially reliant on comprehensive meter information and credible billing datasets which are rarely available in most utilities in Africa.

Tissue section lifting for electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 86-87
Author(s):  
Adrian F. van Dellen
Keyword(s):  
Infectious Disease ◽  
Electron Microscopy ◽  
Tissue Culture ◽  
Organ System ◽  
Surrounding Tissue ◽  
Paraffin Sections ◽  
Surface Areas ◽  
Specific Determination ◽  
High Degree ◽  
Accuracy And Repeatability

The morphologic pathologist may require information on the ultrastructure of a non-specific lesion seen under the light microscope before he can make a specific determination. Such lesions, when caused by infectious disease agents, may be sparsely distributed in any organ system. Tissue culture systems, too, may only have widely dispersed foci suitable for ultrastructural study. In these situations, when only a few, small foci in large tissue areas are useful for electron microscopy, it is advantageous to employ a methodology which rapidly selects a single tissue focus that is expected to yield beneficial ultrastructural data from amongst the surrounding tissue. This is in essence what "LIFTING" accomplishes. We have developed LIFTING to a high degree of accuracy and repeatability utilizing the Microlift (Fig 1), and have successfully applied it to tissue culture monolayers, histologic paraffin sections, and tissue blocks with large surface areas that had been initially fixed for either light or electron microscopy.

Quantification of Silica Uptake by Alveolar Macrophages - An Emperical Scanning Electron Microprobe Method

1982 ◽  
Vol 40 ◽  
pp. 332-333
Author(s):  
V. V. Damiano ◽  
R. P. Daniele ◽  
H. T. Tucker ◽  
J. H. Dauber
Keyword(s):  
Quantitative Analysis ◽  
Alveolar Macrophages ◽  
Bulk Sample ◽  
Silica Particles ◽  
Empirical Method ◽  
Phagocytic Cells ◽  
Calibration Standards ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Scanning Electron

An important example of intracellular particles is encountered in silicosis where alveolar macrophages ingest inspired silica particles. The quantitation of the silica uptake by these cells may be a potentially useful method for monitoring silica exposure. Accurate quantitative analysis of ingested silica by phagocytic cells is difficult because the particles are frequently small, irregularly shaped and cannot be visualized within the cells. Semiquantitative methods which make use of particles of known size, shape and composition as calibration standards may be the most direct and simplest approach to undertake. The present paper describes an empirical method in which glass microspheres were used as a model to show how the ratio of the silicon Kα peak X-ray intensity from the microspheres to that of a bulk sample of the same composition correlated to the mass of the microsphere contained within the cell. Irregular shaped silica particles were also analyzed and a calibration curve was generated from these data.

Assessing Functional Language in School-Aged Children Using Language Sample Analysis

2020 ◽  
Vol 5 (3) ◽  
pp. 622-636
Author(s):  
John Heilmann ◽  
Alexander Tucci ◽  
Elena Plante ◽  
Jon F. Miller
Keyword(s):  
Computer Hardware ◽  
School Age Children ◽  
Functional Language ◽  
School Age ◽  
Clinical Use ◽  
Sample Analysis ◽  
Validity And Reliability ◽  
Language Sample Analysis ◽  
Accuracy And Repeatability ◽  
Language Sample

Purpose The goal of this clinical focus article is to illustrate how speech-language pathologists can document the functional language of school-age children using language sample analysis (LSA). Advances in computer hardware and software are detailed making LSA more accessible for clinical use. Method This clinical focus article illustrates how documenting school-age student's communicative functioning is central to comprehensive assessment and how using LSA can meet multiple needs within this assessment. LSA can document students' meaningful participation in their daily life through assessment of their language used during everyday tasks. The many advances in computerized LSA are detailed with a primary focus on the Systematic Analysis of Language Transcripts (Miller & Iglesias, 2019). The LSA process is reviewed detailing the steps necessary for computers to calculate word, morpheme, utterance, and discourse features of functional language. Conclusion These advances in computer technology and software development have made LSA clinically feasible through standardized elicitation and transcription methods that improve accuracy and repeatability. In addition to improved accuracy, validity, and reliability of LSA, databases of typical speakers to document status and automated report writing more than justify the time required. Software now provides many innovations that make LSA simpler and more accessible for clinical use. Supplemental Material https://doi.org/10.23641/asha.12456719

Performance indicators for student services

1990 ◽  
Vol 18 (1) ◽  
pp. 3-12 ◽  
Author(s):  
Sally Aldridge ◽  
David Legge
Keyword(s):  
Student Services ◽  
Performance Indicators
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