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Artificial neural network and energy budget method to predict daily evaporation of Boudaroua reservoir (northern Morocco)

En-nkhili Hicham, Nizar Imane, Igouzal Mohammed, Touazit Azzeddin, Youness Nizar, Etebaai Issam

Journal of Water and Land Development

2023

no. 57

107--115

Evaporation is one of the main essential components of the hydrologic cycle. The study of this parameter has significant consequences for knowing reservoir level forecasts and water resource management. This study aimed to test the three artificial neural networks (feed-forward, Elman and nonlinear autoregressive network with exogenous inputs (NARX) models) and multiple linear regression to predict the rate of evaporation in the Boudaroua reservoir using the calculated values obtained from the energy budget method. The various combinations of meteorological data, including solar radiation, air temperature, relative humidity, and wind speed, are used for the training and testing of the model’s studies. The architecture that was finally chosen for three types of neural networks has the 4-10-1 structure, with contents of 4 neurons in the input layer, 10 neurons in the hidden layer and 1 neuron in the output layer. The calculated evaporation rate presents a typical annual cycle, with low values in winter and high values in summer. Moreover, air temperature and solar radiation were identified as meteorological variables that mostly influenced the rate of evaporation in this reservoir, with an annual average equal to 4.67 mm∙d-1. The performance evaluation criteria, including the coefficient of determination (R2), root mean square error (RMSE) and mean absolute error (MAE) approved that all the networks studied were valid for the simulation of evaporation rate and gave better results than the multiple linear regression (MLR) models in the study area.

Zastosowanie glikolu polietylenowego jako domieszki utrudniającej parowanie wody z betonu samozagęszczającego się

Swamy Naga Ratna Giri P., Rajesh Kumar G., Sri Rama Chand M., Rathish Kumar P.

Cement Wapno Beton

2017

R. 22/84, nr 1

26--38

Z odkrytych powierzchni betonu zachodzi w sposób ciągły parowanie wody na skutek różnicy ciśnienia pary wodnej w powietrzu i nad wodą na powierzchni betonu. Powoduje to zmniejszenie stosunku w/c w betonie co może powodować niepełną hydratację cementu i pogorszenie jakości betonu. W związku z tym pielęgnacja betonu jest jednym z najważniejszych zabiegów zapewniających dobre właściwości betonu. Samo-pielęgnacja betonu jest jedną z form specjalnego betonu, która zmniejsza wpływ niedostatecznej pielęgnacji spowodowanej źle wyszkoloną kadrą, brakiem wody, lub jej złą jakością. W artykule omówiono zasady stosowania domieszki poli(glikolu etylenowego) o różnej masie cząsteczkowej, dodawanego do mieszanki betonowej, w celu zapewnienia samo-pielęgnacji betonu. Domieszka ta zmniejsza parowanie wody z betonu i poprawia właściwości samozagęszczającego się betonu. Pokazano wpływ tej domieszki na właściwości betonów różnych klas. Porównano tę technologię z pielęgnacją tradycyjną i z brakiem pielęgnacji betonu.

Continuous evaporation of moisture takes place from exposed concrete surfaces due to the potential difference between the vapour and liquid phases. This will reduce the initial water cement ratio resulting in incomplete hydration of cement and thus lowering the quality of concrete. Hence, curing is considered as one of the basic necessities to achieve good performance concrete. Self-curing concrete is one of the special concretes which mitigates insufficient curing due to a variety of reasons including human negligence, scarcity of water, inaccessibility or bad quality of water available for curing. In the present work, polyethylene glycol of different molecular weights are used as self-curing chemicals in self compacting concretes in optimum dosages during the mixing stage. This has ensured reduction in the evaporation of water and enhanced the performance of SCC. This study has clearly brought out the influence of PEG's in different grades of concrete. A comparison was made with conventional curing and concrete without curing.

Problems with determination of evaporation rate and properties of boil-off gas on board LNG carriers

Głomski P., Michalski R.

Journal of Polish CIMAC

2011

Vol. 6, no 1

133-140

The paper discusses selected issues related to the problems of determining boil-off (evaporation) rate (BOR) of liquefied natural gas (LNG) on board LNG carriers. Review of available literature describing theoretical models of LNG boiling-off phenomenon during maritime transport is presented. Given are examples of simulation results of LNG evaporation process based on theoretical analysis. Also presented are methods of determining boil-off rate based on the results of observations of the concerned phenomenon on board selected ships. The paper draws attention to theoretical differences in a daily boil-off gas (BOG) quantity resulting from the adopted method of determining BOR. Namely, in some publications BOR values refer to the loaded quantity of LNG (or even to the ship’s cargo carrying capacity), and in the rest to the current quantity on board. The paper outlines resulting theoretical differences in quantity of cargo remaining on board. Addressed are also issues related with variable, in the course of the voyage, BOG (and thus LNG) composition determining its heating value, which is of particular importance in the case of its use as a fuel for ship’s engines.