scholarly journals Can water evaporation rates be enhanced by employing a different polar ambient?

2020 ◽  
Author(s):  
Ashish Karn ◽  
Jonathan Ambs ◽  
Shashank Singh Deo ◽  
Ayush Vyas ◽  
Ayush Dwivedi ◽  
...  
Keyword(s):  
Surface Area ◽  
Evaporation Rate ◽  
Practical Interest ◽  
Underlying Mechanism ◽  
Water Desalination ◽  
Water Evaporation ◽  
Great Practical Interest ◽  
Conventional Methods ◽  
Increasing Temperature ◽  
Temperature Surface

Enhancing evaporation rates are of great practical interest in many technological applications such as water desalination or drying in industry. Since the conventional methods of increasing evaporation viz. increasing temperature, surface area etc. may not be always practically feasible or economical, novel methods of evaporation enhancement are necessary. The current study explores the possibility of evaporation enhancement by introducing a Tetrafluoroethane gas ambient under different conditions of heating and circulation. Depending upon the temperature and circulation conditions, as enhancement of 58 to 375% in evaporation rate has been measured and physical explanations into the underlying mechanism have been suggested.

scholarly journals SIZING AND EXPERIMENTAL STUDY OF A SOLAR STILL FOR THE PRODUCTIVITY OF WATER DESALINATION IN SOUTH-WEST OF ALGERIA – BECHAR: التصميم والدراسة التجريبية لجهاز التقطير الشمسي لإنتاجية تحلية المياه في جنوب غرب الجزائر – بشار

2020 ◽  
Vol 4 (4) ◽  
Author(s):  
Abdelkarim Maamar Abdelkader, Bounegta Bachir Mohammed
Keyword(s):  
Drinking Water ◽  
Free Surface ◽  
Surface Area ◽  
Evaporation Rate ◽  
Salt Content ◽  
Experimental Studies ◽  
Water Desalination ◽  
Solar Still ◽  
Free Surface Area ◽  
The Third World

Algeria, like many countries belonging mostly to the Third World, has considerable water resources saline (salt content ranging between 1500 and 2000 ppm, exceeding the required standards for drinking water and therefore unfit for consumption). We must therefore think of making use these huge reserves interested in desalination techniques. The stain majored is therefore to achieve a distiller solar plan which meets these needs in drinking water. The absorber surface of the modified solar still is coated with black enamel paint and covered with copper chips. The evaporation rate of the water in the solar still is directly proportional to the exposure area of the water. Thus the productivity of the solar still increases with the free surface area of the water in the basin. The distillate yield was found to have improved considerably, especially when the water depth was high. The study also indicated some design features that would further enhance the improvement in output due to the modification made, the evaporation rate is proportional to the temperature of the free surface area of the water only. A general model based on heat transfer balances in each component of the system was developed to predict the mass of freshwater. The efficiency of this still was about 65% and can produce about 5.13 l/m2 per day, experimental studies and the outcomes are discussed in the article. We propose a new design of the cascading solar desalination still with obstacles and preheating of inlet water.

Intercalation of uranium hexafluoride into graphite

1985 ◽  
Vol 50 (4) ◽  
pp. 947-955 ◽  
Author(s):  
Karel Klouda ◽  
Václav Rak ◽  
Josef Vachuška
Keyword(s):  
Carbon Atom ◽  
Surface Area ◽  
Gaseous Phase ◽  
Uranium Hexafluoride ◽  
Graphite Particles ◽  
Fluorination Agent ◽  
Increasing Temperature ◽  
Elementary Fluorine

Intercalation of UF6 into graphite, both from the gaseous phase and from the Ledon 113 solution, was studied. The amount of intercalated UF6 from the gaseous phase was found to be inversely proportional to the size of graphite particles. Intercalation increases with the increasing temperature and surface area of graphite. The contact of gaseous UF6 with graphite led to the formation of β-UF5 that is not intercalated. In the Ledon solution, β-UF5 is not formed. "Passivation" of graphite by elementary fluorine also prevents the formation of β-UF5 but the amount of intercalated UF6 decreases. The intercalation of UF6 into graphite from the gaseous phase is accompanied by the increase of the distance between the parallel carbon atom layers up to the values of about 884 pm. Ternary intercalates graphite-UF6-Ledon 113 are formed during the intercalation of UF6 from the Ledon 113 solutions and the distance between the parallel carbon atom layers is 848-875 pm. Thermogravimetry in the presence of air revealed that the binary intercalates graphite-UF6 decompose in a 3-step reaction while the ternary intercalates decompose in a 4-step reaction. In both cases uranium hexafluoride is not released but acts as a fluorination agent on the graphite carbon.

scholarly journals Engineering Water and Solute Dynamics and Maximal Use of CNT Surface Area for Efficient Water Desalination

ACS Omega ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 6826-6847 ◽  
Author(s):  
Asieh Sadat Kazemi ◽  
Ali Akbar Noroozi ◽  
Anousha Khamsavi ◽  
Ali Mazaheri ◽  
Seiyed Mossa Hosseini ◽  
...  
Keyword(s):  
Surface Area ◽  
Water Desalination ◽  
Solute Dynamics

scholarly journals Highly efficient evaporative cooling by all-day water evaporation using hierarchically porous biomass

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jihun Choi ◽  
Hansol Lee ◽  
Bokyeong Sohn ◽  
Minjae Song ◽  
Sangmin Jeon
Keyword(s):  
Porous Structure ◽  
Fiber Length ◽  
Evaporation Rate ◽  
Water Evaporation ◽  
Thickness Direction ◽  
Hierarchically Porous ◽  
Hierarchically Porous Structure ◽  
Length Direction ◽  
Luffa Sponge ◽  
Fiber Thickness

AbstractWe developed a 3D solar steam generator with the highest evaporation rate reported so far using a carbonized luffa sponge (CLS). The luffa sponge consisted of entangled fibers with a hierarchically porous structure; macropores between fibers, micro-sized pores in the fiber-thickness direction, and microchannels in the fiber-length direction. This structure remained after carbonization and played an important role in water transport. When the CLS was placed in the water, the microchannels in the fiber-length direction transported water to the top surface of the CLS by capillary action, and the micro-sized pores in the fiber-thickness direction delivered water to the entire fiber surface. The water evaporation rate under 1-sun illumination was 3.7 kg/m2/h, which increased to 14.5 kg/m2/h under 2 m/s wind that corresponded to the highest evaporation rate ever reported under the same condition. The high evaporation performance of the CLS was attributed to its hierarchically porous structure. In addition, it was found that the air temperature dropped by 3.6 °C when the wind passed through the CLS because of the absorption of the latent heat of vaporization. The heat absorbed by the CLS during water evaporation was calculated to be 9.7 kW/m2 under 1-sun illumination and 2 m/s wind, which was 10 times higher than the solar energy irradiated on the same area (1 kW/m2).

scholarly journals Experimental Measurements of the Water Evaporation Rate of a Physical Model

2017 ◽  
Vol 25 (1) ◽  
pp. 19-23 ◽  
Author(s):  
Róbert Turza ◽  
Belo B. Füri
Keyword(s):  
Energy Demand ◽  
Evaporation Rate ◽  
High Water ◽  
Hvac Systems ◽  
Swimming Pool ◽  
Water Evaporation ◽  
Specific Enthalpy ◽  
High Water Content ◽  
Indoor Environments ◽  
Indoor Swimming Pool

Abstract As the number of indoor swimming pools and wellness centers are currently growing, it is necessary to concentrate on the parameters of indoor environments. These parameters are necessary for the design of the HVAC systems that operate these premises. In indoor swimming-pool facilities, the energy demand is large due to ventilation losses from exhaust air. Since water evaporates from a pool’s surface, exhaust air has a high water content and specific enthalpy. In this paper the results of the water evaporation rate measured from swimming pool surfaces at higher thermal water temperatures are described.

scholarly journals Controlling water evaporation through self-assembly

2016 ◽  
Vol 113 (37) ◽  
pp. 10275-10280 ◽  
Author(s):  
Kevin Roger ◽  
Marianne Liebi ◽  
Jimmy Heimdal ◽  
Quoc Dat Pham ◽  
Emma Sparr
Keyword(s):  
Self Assembly ◽  
Feedback Loop ◽  
Ambient Air ◽  
Underlying Mechanism ◽  
Water Evaporation ◽  
Air Humidity ◽  
X Ray ◽  
X Ray Scattering ◽  
Composition And Structure ◽  
Living Organisms

Water evaporation concerns all land-living organisms, as ambient air is dryer than their corresponding equilibrium humidity. Contrarily to plants, mammals are covered with a skin that not only hinders evaporation but also maintains its rate at a nearly constant value, independently of air humidity. Here, we show that simple amphiphiles/water systems reproduce this behavior, which suggests a common underlying mechanism originating from responding self-assembly structures. The composition and structure gradients arising from the evaporation process were characterized using optical microscopy, infrared microscopy, and small-angle X-ray scattering. We observed a thin and dry outer phase that responds to changes in air humidity by increasing its thickness as the air becomes dryer, which decreases its permeability to water, thus counterbalancing the increase in the evaporation driving force. This thin and dry outer phase therefore shields the systems from humidity variations. Such a feedback loop achieves a homeostatic regulation of water evaporation.

scholarly journals Oxidized BPL Carbons

1993 ◽  
Vol 10 (1-4) ◽  
pp. 75-84 ◽  
Author(s):  
S.S. Barton ◽  
M.J.B. Evans ◽  
J.A.F. Macdonald
Keyword(s):  
Nitric Acid ◽  
Surface Area ◽  
Water Adsorption ◽  
Adsorption Properties ◽  
Bet Surface Area ◽  
Adsorption Sites ◽  
A Value ◽  
Nitrogen Desorption ◽  
Oxidized Carbon ◽  
Increasing Temperature

A series of oxidized carbons has been prepared by treatment of the carbon with concentrated nitric acid at various temperatures, and the surface and adsorption properties of the prepared carbons studied. Water adsorption was modelled using a recently derived equation capable of predicting a value for the primary adsorption sites on the surface of a microporous carbon while fitting the experimentally determined isotherm at high relative pressures. The concentration of primary sites was seen to increase with increasing temperature of oxidation. The very highly oxidized carbon samples were found to have a significantly lower BET surface area determined from nitrogen desorption at 77 K and higher apparent density measured from mercury displacement.

scholarly journals Preparation and characterization of activated carbons from albizia saman pod

2017 ◽  
Vol 36 (3) ◽  
pp. 44-53
Author(s):  
G. D. Akpen ◽  
M. I. Aho ◽  
N. Baba
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Activated Carbons ◽  
High Surface ◽  
High Surface Area ◽  
Volatile Matter ◽  
Sieve Analysis ◽  
Albizia Saman ◽  
Temperature Surface

Activated carbon was prepared from the pods of Albizia saman for the purpose of converting the waste to wealth. The pods were thoroughly washed with water to remove any dirt, air- dried and cut into sizes of 2-4 cm. The prepared pods were then carbonised in a muffle furnace at temperatures of 4000C, 5000C, 6000C ,7000C and 8000C for 30 minutes. The same procedure was repeated for 60, 90, 120 and 150 minutes respectively. Activation was done using impregnationratios of 1:12, 1:6, 1:4, 1:3, and 1:2 respectively of ZnCl2 to carbonised Albizia saman pods by weight. The activated carbon was then dried in an oven at 1050C before crushing for sieve analysis. The following properties of the produced Albizia saman pod activated carbon (ASPAC) were determined: bulk density, carbon yield, surface area and ash, volatile matter and moisture contents. The highest surface area of 1479.29 m2/g was obtained at the optimum impregnation ratio, carbonization time and temperature of 1:6, 60 minutes and 5000C respectively. It was recommended that activated carbon should be prepared from Albizia saman pod with high potential for adsorption of pollutants given the high surface area obtained.Keywords: Albizia saman pod, activated carbon, carbonization, temperature, surface area

scholarly journals Calculation of Water Evaporative Cooling Systems in Animal Husbandry

2020 ◽  
pp. 35-38
Author(s):  
N.N. Novikov ◽  
Keyword(s):  
Air Conditioning ◽  
Evaporation Rate ◽  
Evaporative Cooling ◽  
Animal Husbandry ◽  
Water Evaporation ◽  
Cooling Systems ◽  
Temperature And Humidity ◽  
Hot Weather ◽  
Livestock Building ◽  
Air Exchange

A method for calculating the parameters of the microclimate in a livestock building using water-evaporative air conditioning is described. It makes it possible to choose a rational temperature and humidity conditions for a room in hot weather, calculate the required air exchange, water evaporation rate and select the appropriate equipment.

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