scholarly journals Multi-Agent Simulation of Iceberg Mass Loss during Its Energy-Efficient Towing for Freshwater Supply

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4031
Author(s):  
Sergiy Filin ◽  
Iouri Semenov ◽  
Ludmiła Filina-Dawidowicz

The problem of freshwater deficit in the last decade has progressed, not only in Africa or Asia, but also in European countries. One of the possible solutions is to obtain freshwater from drifting icebergs. The towing of large icebergs is the topic analyzed in various freshwater supply projects conducted in different zone-specific regions of the world. These projects show general effects of iceberg transport efficiency but do not present a detailed methodology for the calculation of their mass losses. The aim of this article is to develop the methodology to calculate the mass losses of icebergs transported on a selected route. A multi-agent simulation was used, and the numerical model to estimate the melting rate of the iceberg during its energy-efficient towing was developed. Moreover, the effect of towing speed on the iceberg’s mass loss was determined. It was stated that the maximum use of ocean currents, despite longer route and increased transport time, allows for energy-efficient transport of the iceberg. The optimal towing speed of the iceberg on the selected route was recommended at the range of 0.4–1 m/s. The achieved results may be of interest to institutions responsible for sustainable development and dealing with water resources and freshwater supply.

2014 ◽  
Vol 5 (1) ◽  
pp. 35-50
Author(s):  
Yudai Arai ◽  
Tomoko Kajiyama ◽  
Noritomo Ouchi

In light of the rapid growth of social networks around the world, this study analyses the impact of social networks on the diffusion of products and demonstrates the effective way to diffuse products in the society where social networks play an important role. We construct a consumer behaviour model by multi-agent simulation taking the movie market as an example. After validating it by using data from 13 US movies, we conduct simulations. Our simulation results show that the impact of social networks on the diffusion differs according to the customers’ expectations and evaluation for a movie. We also demonstrate the effective weekly advertising budget allocations corresponding to the types of movies. We find that the difference of weekly advertising budget allocations gives greater impact on the diffusion with the growth of social networks. This paper provides firm’s managers with important suggestions for diffusion strategy considering the impact of social networks.


Author(s):  
Yuto Omae ◽  
Jun Toyotani ◽  
Kazuyuki Hara ◽  
Yasuhiro Gon ◽  
Hirotaka Takahashi ◽  
...  

As of Aug. 2020, coronavirus disease 2019 (COVID-19) is still spreading in the world. In Japan, the Ministry of Health, Labour and Welfare developed “COVID-19 Contact-Confirming Application (COCOA),” which was released on June 19, 2020. By utilizing COCOA, users can know whether or not they had contact with infected persons. If those who had contact with infected individuals keep staying at home, they may not infect those outside. However, effectiveness decreasing the number of infected individuals depending on the app’s various usage parameters is not clear. If it is clear, we could set the objective value of the app’s usage parameters (e.g., the usage rate of the total populations) and call for installation of the app. Therefore, we develop a multi-agent simulator that can express COVID-19 spreading and usage of the apps, such as COCOA. In this study, we describe the simulator and the effectiveness of the app in various scenarios. The result obtained in this study supports those of previously conducted studies.


2018 ◽  
pp. 113-119
Author(s):  
Gennady Ya. Vagin ◽  
Eugene B. Solntsev ◽  
Oleg Yu. Malafeev

The article analyses critera applying to the choice of energy efficient high quality light sources and luminaires, which are used in Russian domestic and international practice. It is found that national standards GOST P 54993–2012 and GOST P 54992– 2012 contain outdated criteria for determining indices and classes of energy efficiency of light sources and luminaires. They are taken from the 1998 EU Directive #98/11/EU “Electric lamps”, in which LED light sources and discharge lamps of high intensity were not included. A new Regulation of the European Union #874/2012/EU on energy labelling of electric lamps and luminaires, in which these light sources are taken into consideration, contains a new technique of determining classes of energy efficiency and new, higher classes are added. The article has carried out a comparison of calculations of the energy efficiency classes in accordance with GOST P 54993 and with Regulation #874/2012/EU, and it is found out that a calculation using GOST P 54993 gives underrated energy efficiency classes. This can lead to interdiction of export for certain light sources and luminaires, can discredit Russian domestic manufacturer light sources and does not correspond to the rules of the World Trade Organization (WTO).


2020 ◽  
Vol 16 (1) ◽  
pp. 62-70 ◽  
Author(s):  
Narimane Rezgui ◽  
Danica Simić ◽  
Choayb Boulahbal ◽  
Dejan Micković

Background: Erosive wear causes increase in the bore diameter of firearms barrels and nozzles. Most responsible factors for this erosion are friction and heat generated during the shot. Protection from erosive wear is very important for gun tube life cycle, and various protection methods are used: adding phlegmatizers in gunpowder composition or applying protective layers on the gun bore inner surface. Objective: In this research, a possibility is examined to protect the surface of a nozzle exposed to gunpowder erosion applying a layer of tungsten disulfide fullerene-like nanoparticles, IF-WS2, known as outstanding solid lubricant of a great mechanical resistance. Methods: Nanoparticles on the nozzle surface before and after the gunfire tests were observed using scanning electron microscopy/energy dispersive X-ray spectroscopy. Gunfire tests were performed on designed erosion device. Temperatures in the defined position near the affected surface were measured with thermocouples and compared for the nozzles with and without nanoprotection, as well as the nozzle mass loss after each round. Results: For the sample with IF-WS2 lower temperatures after firing and lower mass losses were observed. Mass loss after first round was 25.6% lower for the sample with protective nanoparticles layer, and the total mass loss was about 5% lower after five rounds. After the first round the nozzle without IF-WS2 was heated up to a temperature which was for 150.8°C higher than the nozzle with IF-WS2. Conclusion: Protective function of IF-WS2 is the most pronounced for the first round. The observed results encourage its further application in firearms gun bores protection.


RSC Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 2427-2436
Author(s):  
Eyal Merary Wormser ◽  
Oded Nir ◽  
Eran Edri

The desalination of brackish water provides water to tens of millions of people around the world, but current technologies deplete much needed nutrients from the water, which is determinantal to both public health and agriculture.


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