Experimental investigation of ice nucleation by different types of aerosols in the aerosol chamber AIDA: implications to microphysics of cirrus clouds

2005 ◽  
Vol 14 (4) ◽  
pp. 485-497 ◽  
Author(s):  
Alexander Mangold ◽  
Robert Wagner ◽  
Harald Saathoff ◽  
Ulrich Schurath ◽  
Carsten Giesemann ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Ice Nucleation ◽  
Cirrus Clouds ◽  
Different Types ◽  
Aerosol Chamber

scholarly journals Exploring the uncertainties in the aviation soot–cirrus effect

2021 ◽  
Vol 21 (23) ◽  
pp. 17267-17289
Author(s):  
Mattia Righi ◽  
Johannes Hendricks ◽  
Christof Gerhard Beer
Keyword(s):  
Radiative Forcing ◽  
Climate Model ◽  
Internal Variability ◽  
Reanalysis Data ◽  
Ice Nucleation ◽  
Cirrus Clouds ◽  
Model Studies ◽  
Model Dynamics ◽  
Analogous Model ◽  
The Impact

Abstract. A global aerosol–climate model, including a two-moment cloud microphysical scheme and a parametrization for aerosol-induced ice formation in cirrus clouds, is applied in order to quantify the impact of aviation soot on natural cirrus clouds. Several sensitivity experiments are performed to assess the uncertainties in this effect related to (i) the assumptions on the ice nucleation abilities of aviation soot, (ii) the representation of vertical updrafts in the model, and (iii) the use of reanalysis data to relax the model dynamics (the so-called nudging technique). Based on the results of the model simulations, a radiative forcing from the aviation soot–cirrus effect in the range of −35 to 13 mW m−2 is quantified, depending on the assumed critical saturation ratio for ice nucleation and active fraction of aviation soot but with a confidence level below 95 % in several cases. Simple idealized experiments with prescribed vertical velocities further show that the uncertainties on this aspect of the model dynamics are critical for the investigated effect and could potentially add a factor of about 2 of further uncertainty to the model estimates of the resulting radiative forcing. The use of the nudging technique to relax model dynamics is proved essential in order to identify a statistically significant signal from the model internal variability, while simulations performed in free-running mode and with prescribed sea-surface temperatures and sea-ice concentrations are shown to be unable to provide robust estimates of the investigated effect. A comparison with analogous model studies on the aviation soot–cirrus effect show a very large model diversity, with a conspicuous lack of consensus across the various estimates, which points to the need for more in-depth analyses on the roots of such discrepancies.

Experimental Investigation of Input Device Suitability for CAD Operations

2006 ◽  
Author(s):  
Sudheer Bayanker ◽  
Joshua D. Summers ◽  
Anand K. Gramopadhye
Keyword(s):  
Experimental Investigation ◽  
Human Computer Interaction ◽  
User Interfaces ◽  
Undergraduate Student ◽  
Computer Aided Design ◽  
Completion Time ◽  
Input Device ◽  
Computer Aided ◽  
Different Types ◽  
Aided Design

This paper presents an experimental investigation into input suitability for human-computer interaction during computer aided design operations. Specifically, three types of operations, synthesis, interrogation, and modification, are examined with respect to three different types of user interfaces, mouse, direct tablet, and indirect tablet. The study, using undergraduate student participants in an introductory engineering graphics course, demonstrates that the mouse performs the highest across the dimensions of completion time and number of errors. However, the direct tablet, using a pen like device directly on the visualization screen, shows promise.

An experimental investigation of the role of different types of iconic gesture in communication

Gesture ◽  
2002 ◽  
Vol 1 (2) ◽  
pp. 129-149 ◽  
Author(s):  
Geoffrey Beattie ◽  
Heather Shovelton
Keyword(s):  
Experimental Investigation ◽  
Semantic Features ◽  
Accuracy Score ◽  
Iconic Gesture ◽  
Reliable Effect ◽  
Fundamental Conception ◽  
Different Types ◽  
Original Story ◽  
The Relationship

Respondents, who had either seen or not seen a sample of the iconic gestures that encoders produce when narrating a story, answered questions about the original story and it was found that the overall accuracy score for respondents who saw the iconic gestures in addition to hearing the speech was 56.8% compared to 48.6% for speech only. This was a highly reliable effect and suggests that iconic gestures are indeed communicative. Character viewpoint gestures were also significantly more communicative than observer viewpoint gestures particularly about the semantic feature relative position, but the observer viewpoint gestures were effective at communicating information, particularly about the semantic features speed and shape. There were no significant correlations between the amount of information that gestures added to speech and the amount they conveyed in its absence, which suggests that the relationship between speech and gesture is not fixed but variable. The implications of this research for our fundamental conception of iconic gestures are considered.

scholarly journals Experimental Investigation on Ethanol-Petrol Blends Operating with a Petrol Engine: An Overview

2015 ◽  
Vol 773-774 ◽  
pp. 465-469
Author(s):  
Nazrul Atan ◽  
Azizul Mokhtar ◽  
Najib Rahman ◽  
Amir Khalid
Keyword(s):  
Experimental Investigation ◽  
Alternative Fuels ◽  
Gasoline Engine ◽  
Review Paper ◽  
Engine Performance ◽  
Petrol Engine ◽  
New Approach ◽  
Petroleum Price ◽  
Different Types ◽  
Performance And Emissions

The use of biopetrol fuel as alternative fuels in gasoline engine has been around for many years and Ethanol-petrol has the potential to be used as alternative fuel that can reduce the total CO2emission from internal petrol engine. However, the changes of bio-petrol is a very complex and need further understanding for researchers due to the relevance of the increase in the petroleum price and the future environmental regulation. This review paper focuses to ascertain a new approach in potential on ethanol-petrol blends operating with a petrol engine especially the effects of ethanol gas petrol blending ratio and variant types of ethanol on performance and emissions of petrol engine. It is shown that the variant in biopetrol blending ratio and engine operational condition are reduced engine-out emissions and increased efficiency. This paper presents on a review on three different types of ethanol like sugar cane, wheat and corn with various blended rates. Investigation framework study on how to complete the research is also included in this paper.Keywords: biopetrol, petrol engine, performance, emissions, biopetrol fuel properties

scholarly journals Dependence of homogeneous crystal nucleation in water droplets on their radii and its implication for modeling the formation of ice particles in cirrus clouds

2017 ◽  
Vol 19 (30) ◽  
pp. 20075-20081 ◽  
Author(s):  
Yuri S. Djikaev ◽  
Eli Ruckenstein
Keyword(s):  
Nucleation Rate ◽  
Ice Nucleation ◽  
Cirrus Clouds ◽  
Crystal Nucleation ◽  
Water Droplets ◽  
Ice Particles ◽  
Homogeneous Crystal

Dependence of the ice-nucleation-rate in water droplets on their radii and temperature is determined by taking into account volume-based and surface-stimulated modes.

Experimental Investigation of Convective Cells Generated by Side Walls in Solar Ponds Using Various Salts

1997 ◽  
Vol 119 (4) ◽  
pp. 292-297 ◽  
Author(s):  
B. A. Jubran ◽  
J. A. Iweida ◽  
N. M. Haimour
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Sodium Chloride ◽  
Potassium Chloride ◽  
Ammonium Sulphate ◽  
Heated Wall ◽  
Solar Ponds ◽  
Different Types ◽  
Side Walls ◽  
Convective Cells

This paper reports an experimental investigation to study the effect of various parameters that might affect the generation of convective cells in solar ponds with sloping walls. The parameters studied include the variation of the angles of the walls, types of salt used, and the surface roughness of the sloping wall. Four angles were used: 90, 60, 45 and 30, as well as four different types of salts: sodium chloride, potassium chloride, ammonium Sulphate, and carnalite. It was found that increasing the sloping angle of the heated wall of the pond tends to decrease the activity of the convective cells. Furthermore, the growth rate of the convective cells is very much dependent on the type of salt. The results indicate that carnalite and ammonium sulphate tend to have low growth rates of convective cells compared with sodium chloride and potassium chloride. Finally, the surface roughness of the heated wall tends to reduce the activity of the convective cells.

Primary ice nucleation in orographic cirrus clouds: A numerical simulation of the microphysics

1999 ◽  
Vol 125 (557) ◽  
pp. 1637-1667 ◽  
Author(s):  
A. Spice ◽  
D. W. Johnson ◽  
P. R. A. Brown ◽  
A. G. Darlison ◽  
C. P. R. Saunders
Keyword(s):  
Numerical Simulation ◽  
Ice Nucleation ◽  
Cirrus Clouds

scholarly journals Efficiency of the deposition mode ice nucleation on mineral dust particles

2006 ◽  
Vol 6 (1) ◽  
pp. 1539-1577 ◽  
Author(s):  
O. Möhler ◽  
P. R. Field ◽  
P. Connolly ◽  
S. Benz ◽  
H. Saathoff ◽  
...  
Keyword(s):  
Dust Particle ◽  
Formation Rate ◽  
Ice Nucleation ◽  
Dust Particles ◽  
Saturation Ratio ◽  
Particle Properties ◽  
Aerosol Chamber ◽  
Aerosol Fraction ◽  
Takla Makan Desert ◽  
Deposition Mode

Abstract. The deposition mode ice nucleation efficiency of various dust aerosols was investigated at cirrus cloud temperatures between 196 K and 223 K using the aerosol chamber facility AIDA (Aerosol Interaction and Dynamics in the Atmosphere). Arizona test dust (ATD) as a reference material and two dust samples from the Takla Makan desert in Asia (AD1) and Sahara (SD2) were used for the experiments at simulated cloud conditions. The dust particle sizes were almost lognormally distributed with mode diameters between 0.3 µm and 0.5 µm and geometric standard deviations between 1.6 and 1.9. Deposition ice nucleation was most efficient on ATD particles with ice-active particle fractions of about 0.6 and 0.8 at an ice saturation ratio Si<1.15 and temperatures of 223 K and 209 K, respectively. No significant change of the ice nucleation efficiency was found in up to three subsequent cycles of ice activation and evaporation with the same ATD aerosol. The desert dust samples SD2 and AD1 showed a significantly lower fraction of active deposition nuclei, about 0.25 at 223 K and Si<1.35. For all samples the ice activated aerosol fraction could be approximated by an exponential equation as function of Si. This formulation of ice activation spectra may be used to calculate the formation rate of ice crystals in models, if the number concentration of dust particles is known. More experimental work is needed to quantify the variability of the ice activation spectra as function of the temperature and dust particle properties.

scholarly journals Aquaponics for Food Production in Different Growing Beds

2019 ◽  
Vol 8 (3) ◽  
pp. 6103-6106
Keyword(s):  
Experimental Investigation ◽  
Food Production ◽  
Fish Waste ◽  
Hydroponic System ◽  
Coir Pith ◽  
Nutrient Supplements ◽  
Different Types ◽  
Coconut Coir ◽  
Fish Tank ◽  
Aquaculture Water

Soil is the most preferred medium for growth of vegetation worldwide.An experimental investigation has been carried out to study the efficiency of a system to grow plants without the presence of soil called aquaponics .Aquaponics is the process of growing plants and fish and it is combination of hydroponics combined with aquaculture. Water from an aquaculture which is filled with nutrients is transferred to hydroponic system which is used by the plants as nutrient supplements and then the water is recycled back to the fish tank. Ammonia in fish waste will be broken down by bacteria which will be converted into nitrites and then to nitrates. Nitrates thus produced can be used as a natural fertilizer to grow plants.Two different types of aqua phonic grow mediumsuch as clay pebbles and coconut coir pith experimented and compared for two different crops usingaquaphonic technique.

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