Air Dryers in Railway Service: History, Performance and Present Status

Joint Rail ◽  
2002 ◽  
Author(s):  
Jerome R. Pier
Keyword(s):  
Relative Humidity ◽  
Present Status ◽  
Compressed Air ◽  
Cold Weather ◽  
Cold Climates ◽  
Water Condensation ◽  
History Of ◽  
Maintenance Requirements

Pneumatic systems in railway applications are vulnerable to water condensation as a result of the cooling of compressed air. This water tends to cause corrosion, degrade lubricants and freeze in cold weather, causing malfunction in brake systems and other pneumatic devices. Prevailing practice for the control of condensation until the early 70’s consisted of cooling the compressed air followed by reduction in pressure to lower the relative humidity. These methods were less than perfect and frozen systems remained a major cause of train delays in cold climates and, in all climates, water continued to corrode devices and emulsify lubricants, increasing maintenance requirements. Regenerating desiccant type air dryers offered a solution. This paper deals with the history of air dryers in railway service, the technologies involved, and the broad significance to the industry.

scholarly journals Optimization of bioinspired triangular patterns for water condensation and transport

2019 ◽  
Vol 377 (2150) ◽  
pp. 20190127 ◽  
Author(s):  
Dong Song ◽  
Bharat Bhushan
Keyword(s):  
Relative Humidity ◽  
Pressure Gradient ◽  
Surface Temperature ◽  
Dew Point ◽  
Laplace Pressure ◽  
Theme Issue ◽  
Water Condensation ◽  
Water Collection ◽  
Condensed Water ◽  
Droplet Condensation

Water condenses on a surface in ambient environment if the surface temperature is below the dew point. For water collection, droplets should be transported to storage before the condensed water evaporates. In this study, Laplace pressure gradient inspired by conical spines of cactus plants is used to facilitate the transport of water condensed in a triangular pattern to the storage. Droplet condensation, transportation and water collection rate within the bioinspired hydrophilic triangular patterns with various lengths and included angles, surrounded by superhydrophobic regions, were explored. The effect of relative humidity was also explored. This bioinspired technique can be used to develop efficient water collection systems. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology (part 2)’.

scholarly journals Study on the improvement of indoor hot and humid environment in Tibetan-style residential areas in northwest Sichuan

2020 ◽  
Vol 165 ◽  
pp. 04074
Author(s):  
Sun Yidan
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Wall Temperature ◽  
Thermal Environment ◽  
Cold Weather ◽  
Living Room ◽  
Residential Areas ◽  
The West ◽  
Solar Radiation Intensity ◽  
Indoor And Outdoor

Indoor and outdoor thermal environment is under a definite impact on the human body, and to a large extent affects the comfort of people living. In this paper, the indoor and outdoor thermal and humidity parameters of Dongma village in the west of Sichuan Province were measured. On the living room and bedroom hot and humid comfort survey, the outside wall temperature and the local climate to do analysis, get January Dongma village typical residential indoor humidity environment, including the temperature of the living room is 6.6~19.5°C, the relative humidity is 28.9~45.3%rH, the bedroom temperature is 3.5~19.8°C, the relative humidity is 35.7~52.8%rH, the outdoor temperature is 2.4~27.4°C, the temperature in the east is -11.1~-3.3°C, -3.9~11.2°C at the west, -8~2.8°C at the south, -10.4~-2.5 °C at the north, 1.6~29.2 °C at the roof, and the solar radiation intensity is 422~739W/m^2. Combined with the above data, it is found that the overall insulation performance of the wall is good, but by the influence of the cold weather outside, the indoor temperature is still low, it is difficult to respond to the comfort needs of residents. The wall temperature is altered due to solar radiation. In view of the current situation of the indoor thermal environment in Dongma village, a series of optimization suggestions are submitted at the end of the paper.

Results from the Compressed Air Tunnel

1935 ◽  
Vol 39 (289) ◽  
pp. 1-30 ◽  
Author(s):  
Ernest F. Relf
Keyword(s):  
Wind Tunnel ◽  
Scale Effect ◽  
Compressed Air ◽  
Measuring Apparatus ◽  
Short Account ◽  
Preliminary Work ◽  
Special Measuring ◽  
History Of ◽  
Exhaustive Study ◽  
Made In

The Compressed Air Wind Tunnel has now been in more or less regular use fpr a little over a year, during which time some interesting results have been accumulated. While these results are not yet by any means complete enough to enable an exhaustive study of scale effect to be made, they are nevertheless of sufficient extent to throw light on several points in respect to scale effect which have hitherto been somewhat obscure, and in particular to show more clearly the relative effects of scale and turbulence on the important phenomenon of the maximum lift of aerofoils.It may be well to review briefly the history of the development of the Compressed Air Tunnel and to give a very short account of the construction of the tunnel at the N.P.L. and of the preliminary work associated with its special measuring apparatus, as no mention of these matters has yet been made in the Society's publications

Debating the Ouroboros of International Law: The Drafting History of Article 31(3)(c)

2007 ◽  
Vol 9 (1) ◽  
pp. 1-31 ◽  
Author(s):  
Panos Merkouris
Keyword(s):  
International Law ◽  
Present Status ◽  
Vienna Convention ◽  
History Of ◽  
The Law ◽  
Droit International ◽  
International Law Commission ◽  
Law Commission

AbstractThe Diversification and expansion of International Law has sparked a series of debates on the present status and future of International Law; even more so, since the ILC decided to tackle the issue of fragmentation. One of the areas of research and controversy has been Article 31(3)(c) of the Vienna Convention on the Law of Treaties which, arguably, enshrines the principle of systemic integration. The aim of this article is to explore the evolution of Article 31(3)(c) from its first inception by the forefathers of international law up to the finalization of the text of the Vienna Convention on the Law of Treaties. By mapping the critical arguments in the three main fora of debate (i.e the Institut de Droit International, the International Law Commission and the Vienna Conference on the Law of treaties) what arises is a series of conclusions with respect to certain aspects of Article 31(3)(c) as well as certain recurring themes in the nature and progress of the discussions. All of the above will show that the drafting history of Article 31(3)(c) seems to suggest that the relevant provision was meant to serve a purpose expressed more concisely by the symbol of Ouroboros rather than of a mere "master-key" to the house of International Law.

scholarly journals Modeling Indoor Relative Humidity and Wood Moisture Content as a Proxy for Wooden Home Fire Risk

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 5050 ◽  
Author(s):  
Torgrim Log
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Moisture Sorption ◽  
Fire Risk ◽  
Cold Weather ◽  
Indoor Climate ◽  
Ambient Conditions ◽  
Wood Panel ◽  
Fire Disaster ◽  
Strong Winds

Severe wooden home conflagrations have previously been linked to the combination of very dry indoor climate in inhabited buildings during winter time, resulting in rapid fire development and strong winds spreading the fire to neighboring structures. Knowledge about how ambient conditions increase the fire risk associated with dry indoor conditions is, however, lacking. In the present work, the moisture content of indoor wooden home wall panels was modeled based on ambient temperature and relative humidity recorded at meteorological stations as the climatic boundary conditions. The model comprises an air change rate based on ambient and indoor (22 °C) temperatures, indoor moisture sources and wood panel moisture sorption processes; it was tested on four selected homes in Norway during the winter of 2015/2016. The results were compared to values recorded by indoor relative humidity sensors in the homes, which ranged from naturally ventilated early 1900s homes to a modern home with balanced ventilation. The modeled indoor relative humidity levels during cold weather agreed well with recorded values to within 3% relative humidity (RH) root mean square deviation, and thus provided reliable information about expected wood panel moisture content. This information was used to assess historic single home fire risk represented by an estimated time to flashover during the studied period. Based on the modelling, it can be concluded that three days in Haugesund, Norway, in January 2016 were associated with very high conflagration risk due to dry indoor wooden materials and strong winds. In the future, the presented methodology may possibly be based on weather forecasts to predict increased conflagration risk a few days ahead. This could then enable proactive emergency responses for improved fire disaster risk management.

scholarly journals Om ou koeie uit die sloot te grawe: is daar lesse te leer uit die verlede? — Enkele kantaantekeninge

Literator ◽  
1994 ◽  
Vol 15 (2) ◽  
pp. 19-34
Author(s):  
W. A.M. Carstens
Keyword(s):  
South Africa ◽  
Present Status ◽  
Business Community ◽  
The Political ◽  
Political Arena ◽  
Letters To The Editor ◽  
The Past ◽  
History Of ◽  
Official Languages ◽  
Letter Writer

This article focuses on views expressed in newspaper articles and in letters to the editor about the future of Afrikaans in a new political dispensation. It seems as if people do not believe that despite the constitutional assurances of November 1993 - Afrikaans will be able to maintain its present status as one of the official languages of South Africa as the mistakes of the past are constantly being thrown into its face. There have been signs in the business community (for example by Toyota, Coca-Cola, BMW, SA Breweries) and in the political arena that English, rather than Afrikaans, is the favoured language. The views expressed in the articles and letters indicate that the Afrikaans community will not accept this attitude and that a new struggle for language rights (especially those of Afrikaans in the light of the history of Afrikaans) could be the result. This struggle could according to one letter writer - have serious consequences for peace in the country after the assumption of power by a new government will come to power after April 27 1994.

A Pilot Compressed Air Engine

2011 ◽  
Vol 22 (8) ◽  
pp. 1105-1113 ◽  
Author(s):  
Afzal Ahmed
Keyword(s):  
Motor Development ◽  
Fossil Fuel ◽  
Solenoid Valve ◽  
Compressed Air ◽  
Good News ◽  
Reciprocating Motion ◽  
Connecting Rod ◽  
History Of Development ◽  
History Of ◽  
Temperature And Pressure

The air car has a history of development - with proponents and critics - since 1687. As the conventional internal combustion car engine is only 20% efficient, it wastes a considerable amount of energy and will not be feasible, if - for whatever reasons - fossil fuel fall short in supply and therefore, extremely expensive. The drawback of an air engine is that, it is light, requires frequent refilling of the compressed air-tank even for short distances, and the temperature and pressure reduce during expansion in the cylinder. Current research is concerned with alleviating these drawbacks. The good news is that, Motor Development International (MDI) Luxembourg has developed an air engine for a car using a specially designed connecting rod. MDI is now building an air car of 75hp costing US $ 17,800.00 for US roads and can travel up to 1000 miles at 96 mph. In the present study, the concept of double acting steam engine is used by replacing steam with compressed air and the reciprocating motion of piston is governed through flywheel using a solenoid valve. The efficiency of the engine based on input energy of compressed air is about 80%.

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