Propellers and Shafting for Sustainable Shipping

Author(s):  
Stan Liviu-Constantin

The importance of the line shafting, tailshaft, propeller, and thrust shaft cannot be over-emphasised. Failure of any one of them will rend the ship inoperable with possible disastrous consequences. Single line shafting is used on the majority of ships, but not in passenger ships and on short voyage ro-ro services where twin screws are employed. Propellers, because they are outside the ship, are often neglected and are usually only inspected when the ship is in drydock. More frequent examination can be undertaken when a ship is alongside and the shafting is being rotated with the turning gear. Damage to the propeller blade can lead to vibrations being set up in the line shafting causing overheating of the shafting bearings, main thrust, etc. The selection of shafting and propeller materials is usually within manufacturers’ specifications and complies with the various classification society requirements as well as the statutory requirements of governments.

1996 ◽  
Vol 76 (06) ◽  
pp. 0939-0943 ◽  
Author(s):  
B Boneu ◽  
G Destelle ◽  

SummaryThe anti-aggregating activity of five rising doses of clopidogrel has been compared to that of ticlopidine in atherosclerotic patients. The aim of this study was to determine the dose of clopidogrel which should be tested in a large scale clinical trial of secondary prevention of ischemic events in patients suffering from vascular manifestations of atherosclerosis [CAPRIE (Clopidogrel vs Aspirin in Patients at Risk of Ischemic Events) trial]. A multicenter study involving 9 haematological laboratories and 29 clinical centers was set up. One hundred and fifty ambulatory patients were randomized into one of the seven following groups: clopidogrel at doses of 10, 25, 50,75 or 100 mg OD, ticlopidine 250 mg BID or placebo. ADP and collagen-induced platelet aggregation tests were performed before starting treatment and after 7 and 28 days. Bleeding time was performed on days 0 and 28. Patients were seen on days 0, 7 and 28 to check the clinical and biological tolerability of the treatment. Clopidogrel exerted a dose-related inhibition of ADP-induced platelet aggregation and bleeding time prolongation. In the presence of ADP (5 \lM) this inhibition ranged between 29% and 44% in comparison to pretreatment values. The bleeding times were prolonged by 1.5 to 1.7 times. These effects were non significantly different from those produced by ticlopidine. The clinical tolerability was good or fair in 97.5% of the patients. No haematological adverse events were recorded. These results allowed the selection of 75 mg once a day to evaluate and compare the antithrombotic activity of clopidogrel to that of aspirin in the CAPRIE trial.


2018 ◽  
Vol 8 (3) ◽  
pp. 231-250
Author(s):  
Young-Soo Park ◽  
◽  
Myoung-Ki Lee ◽  
Dae-Woon Shin ◽  
Sang-Won Park

At production of fabrics, including fabrics for agricultural purpose, an important role is played by the cor-rect adjustment of operation of machine main regulator. The quality of setup of machine main controller is determined by the proper selection of rotation angle of warp beam weaving per one filling thread. In the pro-cess of using the regulator as a result of mistakes in adjustment, wear of transmission gear and backlashes in connections of details there are random changes in threads length. The purpose of the article is the research of property of random errors of basis giving by STB machine regulator. Mistakes can be both negative, and positive. In case of emergence only negative or only positive mistakes operation of the machine becomes im-possible as there will be a consecutive accumulation of mistakes. As a result of experimental data processing for stable process of weaving and the invariable diameter of basis threads winding of threads it is revealed that the random error of giving is set up as linear function of the accidental length having normal distribution. Measurements of accidental deviations in giving of a basis by the main regulator allowed to construct a curve of normal distribution of its actual length for one pass of weft thread. The presented curve of distribution of random errors in giving of a basis is the displaced curve of normal distribution of the accidental sizes. Also we define the density of probability of normal distribution of basis giving errors connected with a margin er-ror operation of the main regulator knowing of which allows to plan ways of their decrease that is important for improvement of quality of the produced fabrics.


The selection of hospital sites is one of the most important choice a decision maker has to take so as to resist the pandemic. The decision may considerably affect the outbreak transmission in terms of efficiency , budget, etc. The main targeted objective of this study is to find the ideal location where to set up a hospital in the willaya of Oran Alg. For this reason, we have used a geographic information system coupled to the multi-criteria analysis method AHP in order to evaluate diverse criteria of physiological positioning , environmental and economical. Another objective of this study is to evaluate the advanced techniques of the automatic learning . the method of the random forest (RF) for the patterning of the hospital site selection in the willaya of Oran. The result of our study may be useful to decision makers to know the suitability of the sites as it provides a high level of confidence and consequently accelerate the power to control the COVID19 pandemic.


2012 ◽  
Vol 17 (4) ◽  
pp. 542-549 ◽  
Author(s):  
Maria Cândida Monteiro ◽  
Mercedes de la Cruz ◽  
Juan Cantizani ◽  
Catalina Moreno ◽  
José R. Tormo ◽  
...  

Natural products are an inexhaustible source for drug discovery. However, the validation and selection of primary screening assays are vital to guarantee a selection of extracts or molecules with relevant pharmacological action and worthy of following up. The assay must be rapid, simple, easy to implement, and produce quick results and preferably at a low cost. In this work, we developed and validated a colorimetric microtiter assay using the resazurin viability dye. The parameters of the resazurin method for high-throughput screening (HTS) using natural extracts against Aspergillus fumigatus were optimized and set up. The extracts plus RPMI-1640 modified medium containing the spores and 0.002% resazurin were added per well. The fluorescence was read after 24 to 30 h of incubation. The resazurin proved to be as suitable as Alamar Blue for determining the minimal inhibitory concentration of different antifungals against A. fumigatus and effective to analyze fungicidal and fungistatic compounds. An HTS of 12 000 microbial extracts was carried out against two A. fumigatus strains, and 2.7% of the extracts displayed antifungal activity. Our group has been the first to use this methodology for screening a collection of natural extracts to identify compounds with antifungal activity against the medically important human pathogen A. fumigatus.


2007 ◽  
Vol 585 ◽  
pp. 323-342 ◽  
Author(s):  
M. LE BARS ◽  
S. LE DIZÈS ◽  
P. LE GAL

The effects of the Coriolis force on the elliptical instability are studied experimentally in cylindrical and spherical rotating containers placed on a table rotating at a fixed rate $\tilde{\Omega}^G$. For a given set-up, changing the ratio ΩG of global rotation $\tilde{\Omega}^G$ to flow rotation $\tilde{\Omega}^F$ leads to the selection of various unstable modes due to the presence of resonance bands, in close agreement with the normal-mode theory. No instability occurs when ΩG varies between −3/2 and −1/2 typically. On decreasing ΩG toward −1/2, resonance bands are first discretized for ΩG<0 and progressively overlap for −1/2 ≪ ΩG < 0. Simultaneously, the growth rates and wavenumbers of the prevalent stationary unstable mode significantly increase, in quantitative agreement with the viscous short-wavelength analysis. New complex resonances have been observed for the first time for the sphere, in addition to the standard spin-over. We argue that these results have significant implications in geo- and astrophysical contexts.


Mousaion ◽  
2016 ◽  
Vol 32 (4) ◽  
pp. 55-74
Author(s):  
Maritha Snyman

In view of the dire state of literacy levels in South Africa and the fact that few literacy programmes provide research reports to evaluate best practices and effectivity, this article reports on the evaluation of a literacy project. The project, inspired by two children, is referred to as the Zoë-reading aloud project and targeted children in and around Upington in the Northern Cape, South Africa. The project was set up according to acknowledged reading promotion principles and it was structured to collect detailed data. Qualitative and quantitative data collection methods were used and a selection of methods provided reliability. The findings of the analysis of a collection of data for a period of 15 months revealed the best practices of the project. It highlights, for example, the need for financial assistance and challenges the concept of family literacy in low-literate and poor communities.


1969 ◽  
Vol 91 (2) ◽  
pp. 168-172
Author(s):  
J. Ansari ◽  
W. Leidenfrost ◽  
R. Oldenburger

A proposed apparatus for controlling temperatures from −190 deg to +650 deg with an estimated accuracy of 0.001 deg C is described. The apparatus utilizes helium as the heat transfer medium. The selection of the gain constants of the controller depends upon the system parameters. The hypothetical case of a solid cylindrical block with an integral plus proportional controller is considered, the differential equations are set up, and a graphical scheme is presented for the selection of the controller constants.


1995 ◽  
Vol 32 (02) ◽  
pp. 141-146
Author(s):  
Martin D. Levin

The increasing demand for marine transportation of agricultural produce under controlled atmosphere (CA) conditions is leading owners of refrigerated ships to provide permanently installed on-board nitrogen generating plants and atmosphere control systems. The selection of the shipboard CA gas generating plant must take into account the vessel type, the cargoes to be carried, and the range of controlled atmosphere conditions to be achieved for different commodities. The shipboard CA gas generating plant can be situated on the ship's weather deck, installed in the vessel's main or auxiliary machinery spaces, located in a separate CA compartment, or a combination of these options. Ventilation of all spaces containing CA generating equipment and pipelines, combined with atmosphere monitoring and alarms, and safety training of all concerned personnel, provides an acceptable level of safety. Experience with installation and operation of shipboard CA systems demonstrates that, with careful attention to sealing of the cargo spaces, proper equipment selection and installation in accordance with classification society guidelines, a successful shipboard CA installation can be achieved.


Author(s):  
Roy Goulding

This series provides a selection of articles from the past. In Fifty years ago: ‘A poisons information service’ the author briefly explores a service set up in the 1960s to offer advice on medicinal, veterinary, agricultural, horticultural, and household poisoning, and after some debate, industrial poisoning.


Sign in / Sign up

Export Citation Format

Share Document