Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for subject:(Fog formation). Showing records 1 – 3 of 3 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters

1. Martikainen, Anu. Fog Removal in the Declines of Underground Mines in Sub-Arctic Regions.

Degree: 2007, Helsinki University of Technology

Fogging is a common safety hazard observed especially in the declines of underground mines located in sub-arctic regions. Fog forms when saturated air loses internal energy by mixing with a colder air stream, by simply ascending through the ventilation system of the mine, or when contact with cold wall-rock decreases air temperature. Studies concerning fogging in underground mines are rare. Technological advances and more complete theoretical knowledge gained by research in many other fields offer possibilities for thorough fogging research in mines. This research aims to better understand underground fog formation, related parameters, characteristics, and fog behaviour. Interviews, literature review, psychrometric and particle concentration measurements, on-site field tests of the existing fog removal methods, and developing and testing a new fog removal approach are used as research methods. The interviews show that there are methods not mentioned in the literature that are used for fog removal in mines. Case studies provide fascinating insight into fogging problems and how to solve them. From literature review the complicated behaviour of fog is uncovered, and the role of visibility, optical attenuation, and droplet size distribution studies are evaluated. Ideas concerning further research are presented according to the findings. Basic study results demonstrate the situation in declines of three underground mines; Pyhäsalmi Mine, Orivesi Mine, and Louhi Mine in Finland. Studies concerning increasing air velocity show that the value suggested by literature to be high enough for fog dispersal, 0.25 m/s, is not nearly enough in the declines of these mines. Installing an additional fan, showed that the change in relative humidity and thus fog thickness was based on the quantity of heat the fan added to the air. Heating decreased fog thickness noticeably. Only local fog removal was observed for both methods. Trials concerning new method development gave mainly positive results. The method is based on the water gathering effect of a net set perpendicular to the airflow. The frame and mesh installation are presented. Seven out of eight tested mesh materials resulted in a decrease of relative humidity and particle concentration. Twelve tests were completed, of which two were material combination tests. Unfortunately only two tests resulted in a noticeable decrease of fog thickness and even in these cases the efficiency was not enough for complete fog removal. The best results were received with aluminium net and a mist eliminator/fibrous filter fabric combination.

Sumuuntuminen on tavallinen turvallisuusriski erityisesti lauhkean vyöhykkeen maanalaisten kaivosten vinoajoteillä. Sumu muodostuu kun vesikyllästetty ilmamassa menettää sisäistä energiaa sekoittuessaan kylmemmän ilmavirran kanssa, noustessaan kaivoksen tuuletusjärjestelmän läpi tai joutuessaan kosketuksiin kylmien kiviseinämien kanssa. Sumututkimukset maanalaisissa kaivoksissa ovat harvinaisia. Tekniset edistysaskeleet ja muilla tieteen aloilla…

Advisors/Committee Members: Helsinki University of Technology, Department of Civil and Environmental Engineering, Laboratory of Rock Engineering.

Subjects/Keywords: mine ventilation; fog formation; fog removal; visibility; psychrometric; particle concentration; kaivostuuletus; sumun muodostus; sumunpoisto; näkyvyys; psykrometria; hiukkaspitoisuus

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Martikainen, A. (2007). Fog Removal in the Declines of Underground Mines in Sub-Arctic Regions. (Thesis). Helsinki University of Technology. Retrieved from http://lib.tkk.fi/Diss/2007/isbn9789512287789/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Martikainen, Anu. “Fog Removal in the Declines of Underground Mines in Sub-Arctic Regions.” 2007. Thesis, Helsinki University of Technology. Accessed September 21, 2019. http://lib.tkk.fi/Diss/2007/isbn9789512287789/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Martikainen, Anu. “Fog Removal in the Declines of Underground Mines in Sub-Arctic Regions.” 2007. Web. 21 Sep 2019.

Vancouver:

Martikainen A. Fog Removal in the Declines of Underground Mines in Sub-Arctic Regions. [Internet] [Thesis]. Helsinki University of Technology; 2007. [cited 2019 Sep 21]. Available from: http://lib.tkk.fi/Diss/2007/isbn9789512287789/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Martikainen A. Fog Removal in the Declines of Underground Mines in Sub-Arctic Regions. [Thesis]. Helsinki University of Technology; 2007. Available from: http://lib.tkk.fi/Diss/2007/isbn9789512287789/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


IUPUI

2. Adhikari, Bishwodeep. The Contributions of Soil Moisture and Groundwater to Non-Rainfall Water Formation in the Namib Desert.

Degree: 2019, IUPUI

Indiana University-Purdue University Indianapolis (IUPUI)

Non-rainfall waters such as fog and dew are considered as important source of water in drylands, and the knowledge of possible sources of its formation is very important to make future predictions. Prior studies have suggested the presence of radiation fog in drylands; however, its formation mechanism still remains unclear. There have been earlier studies on the effects of fog on soil moisture dynamics and groundwater recharge. On the contrary, no research has yet been conducted to understand the contribution of soil moisture and groundwater to fog formation. This study, therefore, for the first time intends to examine such possibility in a fog-dominated dryland ecosystem, the Namib Desert. The study was conducted at three sites representing two different land forms (sand dunes and gravel plains) in the Namib Desert. This thesis is divided into two parts: the first part examines evidences of fog formation through water vapor movement using field observations, and the second part simulates water vapor transport using HYDRUS-1D model. In the first part of the study, soil moisture, soil temperature and air temperature data were analyzed, and the relationships between these variables were taken as one of the key indicators for the linkage between soil water and fog formation. The analysis showed that increase in soil moisture generally corresponds to similar increase in air or soil temperature near the soil surface, which implied that variation in soil moisture might be the result of water vapor movement (evaporated soil moisture or groundwater) from lower depths to the soil surface. In the second part of the study, surface fluxes of water vapor were simulated using the HYDRUS-1D model to explore whether the available surface flux was sufficient to support fog formation. The actual surface flux and cumulative evaporation obtained from the model showed positive surface fluxes of water vapor. Based on the field observations and the HYDRUS-1D model results, it can be concluded that water vapor from soil layers and groundwater is transported through the vadose zone to the surface and this water vapor likely contributes to the formation of non-rainfall waters in fog-dominated drylands, like the Namib Desert.

Advisors/Committee Members: Wang, Lixin, Li, Lin, Jacinthe, Pierre-André.

Subjects/Keywords: HYDRUS-1D; Soil moisture; Volumetric water content; Namib desert; Non-rainfall water; Fog formation

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Adhikari, B. (2019). The Contributions of Soil Moisture and Groundwater to Non-Rainfall Water Formation in the Namib Desert. (Thesis). IUPUI. Retrieved from http://hdl.handle.net/1805/20533

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Adhikari, Bishwodeep. “The Contributions of Soil Moisture and Groundwater to Non-Rainfall Water Formation in the Namib Desert.” 2019. Thesis, IUPUI. Accessed September 21, 2019. http://hdl.handle.net/1805/20533.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Adhikari, Bishwodeep. “The Contributions of Soil Moisture and Groundwater to Non-Rainfall Water Formation in the Namib Desert.” 2019. Web. 21 Sep 2019.

Vancouver:

Adhikari B. The Contributions of Soil Moisture and Groundwater to Non-Rainfall Water Formation in the Namib Desert. [Internet] [Thesis]. IUPUI; 2019. [cited 2019 Sep 21]. Available from: http://hdl.handle.net/1805/20533.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Adhikari B. The Contributions of Soil Moisture and Groundwater to Non-Rainfall Water Formation in the Namib Desert. [Thesis]. IUPUI; 2019. Available from: http://hdl.handle.net/1805/20533

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


ETH Zürich

3. Spiegel, Johanna K. Experimental characterization of fog under the influence of orography and Saharan dust using droplet size spectra and stable water isotopologues in fog droplets.

Degree: 2012, ETH Zürich

Subjects/Keywords: CLOUD STRUCTURE + CLOUD FORMATION (METEOROLOGY); FOG + HAZE + MIST (METEOROLOGY); OROGRAPHIC WIND DISTURBANCES (METEOROLOGY); ATMOSPHERIC IMPURITIES + ATMOSPHERIC DUST (METEOROLOGY); PHYSICAL PROCESSES OF CONDENSATION (METEOROLOGY); METEOROLOGISCHE MODELLE; ISOTOPE GEOCHEMISTRY; ISOTOPENGEOCHEMIE; METEOROLOGICAL MODELS; STAUB UND VERUNREINIGUNGEN IN DER ATMOSPHÄRE (METEOROLOGIE); SAND- UND STAUBFÜHRENDE WINDE (METEOROLOGIE); PHYSIKALISCHE PROZESSE BEI DER KONDENSATION (METEOROLOGIE); KONDENSATIONSKERNE (METEOROLOGIE); CONDENSATION NUCLEI (METEOROLOGY); SAND AND DUST CARRYING WINDS (METEOROLOGY); DUNST + NEBEL (METEOROLOGIE); WOLKENSTRUKTUR + WOLKENBILDUNG + WOLKENAUFLÖSUNG (METEOROLOGIE); OROGRAPHISCHE WINDSTÖRUNGEN (METEOROLOGIE); info:eu-repo/classification/ddc/550; info:eu-repo/classification/ddc/550; Earth sciences; Earth sciences

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Spiegel, J. K. (2012). Experimental characterization of fog under the influence of orography and Saharan dust using droplet size spectra and stable water isotopologues in fog droplets. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/63019

Chicago Manual of Style (16th Edition):

Spiegel, Johanna K. “Experimental characterization of fog under the influence of orography and Saharan dust using droplet size spectra and stable water isotopologues in fog droplets.” 2012. Doctoral Dissertation, ETH Zürich. Accessed September 21, 2019. http://hdl.handle.net/20.500.11850/63019.

MLA Handbook (7th Edition):

Spiegel, Johanna K. “Experimental characterization of fog under the influence of orography and Saharan dust using droplet size spectra and stable water isotopologues in fog droplets.” 2012. Web. 21 Sep 2019.

Vancouver:

Spiegel JK. Experimental characterization of fog under the influence of orography and Saharan dust using droplet size spectra and stable water isotopologues in fog droplets. [Internet] [Doctoral dissertation]. ETH Zürich; 2012. [cited 2019 Sep 21]. Available from: http://hdl.handle.net/20.500.11850/63019.

Council of Science Editors:

Spiegel JK. Experimental characterization of fog under the influence of orography and Saharan dust using droplet size spectra and stable water isotopologues in fog droplets. [Doctoral Dissertation]. ETH Zürich; 2012. Available from: http://hdl.handle.net/20.500.11850/63019

.