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Number of results: 14
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Abstract

The article presents the results of studies on the rate of zinc evaporation in the atmosphere of helium and carbon monoxide (II) carried out with the thermogravimetric method. The estimated values of zinc streams were compared with the values determined based on theoretical relationships.
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Authors and Affiliations

Jerzy Łabaj
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Abstract

In the present paper, the one-dimensional model for heat and mass transfer in fixed coal bed was proposed to describe the thermal and flow characteristics in a coke oven chamber. For the purpose of the studied problem, the analysis was limited to the calculations of temperature field and pyrolytic gas yield. In order to verify the model, its theoretical predictions for temperature distribution during wet coal charge carbonization were compared with the measurement results found in the literature. In general, the investigation shows good qualitative agreement between numerical and experimental data. However, some discrepancy regarding the temperature characteristics at the stage of evaporation was observed.

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Authors and Affiliations

Dariusz Kardaś
Sylwia Polesek-Karczewska
Izabela Wardach-Święcicka
Arkadiusz Grucelski
Sławomir Stelmach
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Abstract

Evaporation and evapotranspiration is crucial part of hydrological and water resource management studies e.g. water footprinting. Proper methods for estimating evaporation/potential evapotranspiration using limited climatic data are critical if the availability of climatic data is extremely limited. In a large scale studies are very often used generalized (modelled or gridded) input data. For a large scale water footprint studies is also important to find methods as simple as possible with quantifiable error. In our study, nine simple temperature-based empirical equations were compared with a long term time series of real evaporation data from a 20 m2 tank at Hlasivo station. In the first step, we used real temperature measured at Hlasivo station for validation of equations. In the second step, the gridded temperature data (interpolated datasets) derived from the meteorological stations were used. For both datasets, the differences between observed and predicted values were categorized into three groups of accuracy and the statistical indices of each equation were calculated. Very good results were achieved with the Hamon equation from 1961 and the Oudin equation for both datasets with index of agreement (d) higher than 0.9, cross-correlation coefficient (R2) around 0.7 and root mean square error (RMSE) around 0.5 mm∙(24 h)–1The Kharrufa equation, which was developed for semi-arid or arid areas, also provides results with sufficient accuracy. Comparison of the results with similar studies showed a lower accuracy of very simple equations against more complex equations, which have RMSE lower than 0.25 mm∙(24 h)–1. But for some kind of studies, quantifiable errors with sufficient accuracy can be more important than the absolute accuracy.

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Authors and Affiliations

Libor Ansorge
Adam Beran
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Abstract

Reservoirs have a very important function in providing multi-sector water requirements. In the future, reservoirs not only serve to store and available water can also be used as disaster mitigation instruments. The completeness of hydrological measurements in reservoirs can be expanded more widely for climate change mitigation. The reliability of the reservoir capacity varies greatly depending on the El-Nino character that occurs among them El-Nino is weak, moderate, strong and very strong. The El-Nino characteristic is very influential on the period of water availability, the increase of evaporation capacity and decrease of reservoir capacity. Analysis of the reliability of the reservoir volume due to El-Nino using the Weibull equation. The deficit reservoir was calculated using the concept of water balance in the reservoir that is the relationship between inflow, outflow, and change of storage at the same time. Based on the results of the analysis showed that the evaporation increase and the decrease of reservoir capacity had a different pattern that is when the evaporation capacity started to increase at the same time the reservoir capacity decreased significantly. The correlation coefficient between evaporation capacity increase and decrease of reservoir water capacity are consecutively –0.828, –0.636, and –0.777 for El- Nino weak, moderate and very strong respectively. At the reservoir capacity reliability of 50% reservoir has a significant deficit. When weak El-Nino the deficit is 2.30∙106 m3, moderate: 6.58∙106 m3, and very strong 8.85∙106 m3.

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Authors and Affiliations

Ussy Andawayanti
I Wayan Yasa
ORCID: ORCID
Mohammad Bisri
Mochamad Sholichin
Sulianto
ORCID: ORCID
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Abstract

Many modern processes for the production and casting of metals and their alloys are carried out in protective gas atmospheres, which protect them, for example, from oxygen pollution. This applies, for example, to titanium, magnesium or aluminum alloys. Most liquid alloys are comprised of constituents that differ in vapor pressures, resulting in harmful phenomenon during melting due to evaporation of some of its components. This harmful process may be limited by the selection of a suitable gas atmosphere in which the liquid metal treatment process is carried out. In the paper, results of study on the impact of the type of gas atmosphere on the rate of evaporation of zinc in argon – hydrogen mixtures are presented. It should be noted that such mixtures are used, for example, in metal welding processes, in which it is also possible to evaporate a component of the so-called liquid metal pool. The research results showed that the rate of zinc evaporation increases with the increase of hydrogen content in the gas atmosphere.
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Authors and Affiliations

T. Matuła
1
ORCID: ORCID

  1. Silesian University of Technology, Faculty of Materials Engineering, 8 Krasińskiego Str., 40-019 Katowice, Poland
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Abstract

Geometry of plate heat exchangers (PHE) is characterized by a complex net of narrow channels. It enhances turbulence and results in better heat transfer performance. Theoretically, larger number of channels (plates) should proportionally increase the PHE heat power capacity. In practice a nonuniform massflow distribution in consecutive flow channels can significantly deteriorate the overall heat exchange performance. The flow maldistribution is one of the most commonly reported exploitation problems and is present in PHE with and without phase-change flows. The presented paper investigates numerically a flow pattern in PHE with evaporation of R410A refrigerant. Various sizes of PHE are considered. The paper introduces a robust methodology to transform the complicated geometry of a real 3D PHE to its 2D representation. It results in orders of magnitude faster calculations and allows for fast evaluation of different geometrical changes of PHE and their effect on flow maldistribution.

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Authors and Affiliations

Paweł Pluszka
Arkadiusz Patryk Brenk
Ziemowit Miłosz Malecha
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Abstract

The presence of noises in the vehicle cabin is an annoyance phenomenon which is significantly affected by the heating, ventilation, and air conditioning (HVAC) system. There are very limited studies reported on the specific type of noise characterisation and validation for both model and vehicle system levels. The present study developed a model of HVAC system that reflects the operation as in real vehicle, and the investigation of the HVAC components were carried out individually to determine which component contributes to the humming-type noise and vibration. The study was conducted under two conditions; idle speed of engine (850 rpm) and operating condition (850–1400 rpm). A ixed blower speed and fullface setting were applied throughout the experimental process. Three different sensors were used for the experiment, which are: accelerometer, tachometer, and microphone. From the results, the compressor and AC pipe components have contributed the most in generating the noise and vibration for both the model and vehicle systems. The findings also highlight that the humming-type noise and vibration were produced in the same operating frequency of 300–400 Hz and 100–300 Hz for idle and operating conditions, respectively, and this result was validated for both model and vehicle system levels.
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Authors and Affiliations

Mohd Hafiz Abdul Satar
1
Ahmad Zhafran Ahmad Mazlan
1
Muhd Hidayat Hamdan
1
Mohd Syazwan Md Isa
1
Muhd Abdul Rahman Paiman
2
Mohd Zukhairi Abd Ghapar
2

  1. The Vibration Lab, School of Mechanical Engineering, Universiti Sains Malaysia 14300 Nibong Tebal, Penang, Malaysia
  2. Testing & Development, Vehicle Development & Engineering, Proton Holdings Berhad, 40000 Shah Alam, Selangor, Malaysia
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Abstract

Heating, ventilation and air conditional (HVAC) system provides a cold ventilation for the comfort of the driver and passengers in a vehicle. However, the vibration induced by the HVAC contributes to a reasonable level of noise emission, and hissing is one of the critical noises. So far, the characterization of hissing noise from the vehicle is least to be reported compared to other type of noises. Hence, this paper investigates the occurrence of hissing noise from several HVAC components. A lab-scale HVAC system was developed to imitate the real-time operations of the vehicle HVAC system. Two engine conditions, namely as ambient and operating conditions, were tested at speed of 850 rpm and 850–1400 rpm, with the blower speed maintained constantly at one level. The result shows that the hissing noise from the labscale HVAC was produced at frequency range of 4000–6000 Hz. The finding also highlights that the main component contributors of noise emission are an evaporator and a thermal expansion valve. The validation with a real vehicle system showed a good consensus whereby the hissing noise was produced at the similar operating frequency ranges. Also, the hissing noise was found to be louder when in an operating condition which could be taken into consideration by the vehicle manufacturers to improve the HVAC design.
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Authors and Affiliations

Mohd Hafiz Abdul Satar
1
Ahmad Zhafran Ahmad Mazlan
1
Muhd Hidayat Hamdan
1
Mohd Syazwan Md Isa
1
Muhd Abdul Rahman Paiman
2
Mohd Zukhairi Abd Ghapar
2

  1. The Vibration Lab, School of Mechanical Engineering, Universiti Sains Malaysia 14300 Nibong Tebal, Penang, Malaysia
  2. Testing & Development, Vehicle Development & Engineering, Proton Holdings Berhad, 40000 Shah Alam, Selangor, Malaysia
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Abstract

Titanium alloys belonging to the group of modern metallic materials used in many industries, including the aerospace industries. Induction crucible vacuum furnaces and induction furnaces with cold crucible are most commonly used for their smelting. When operating these devices, one can deal with an adverse phenomenon of decrease in the content of alloy elements that are characterized by higher equilibrium vapour pressure than the matrix metal or titanium, in the metal bath. In the paper, results of the study on aluminium evaporation from the Ti-Al-Nb, Ti-Al-V and Ti-Al alloys (max 6.2 % wt.) during smelting in a vacuum induction melting (VIM) furnace are presented. The experiments were performed at 10 to 1000 Pa for 1973 K and 2023 K. A significant degree of aluminium loss has been demonstrated during the analysed process. The values of relative aluminium loss for all the alloys ranged from 4 % to 25 %. Lowering the pressure in the melting system from 1000 Pa to 10 Pa resulted in increased values of aluminium evaporation flux from 4.82⋅10-5 to 0.000327 g⋅cm-2⋅s-1 for 1973 K and from 9.28⋅10-5 to 0.000344 g⋅cm-2⋅s-1 for 2023 K. The analysis of the results obtained took into account the value of the actual surface of the liquid metal. In the case of melting metals in an induction furnace, this surface depends on the value of power emitted in the charge. At greater power, we observe a significant increase in the bath surface due to the formation of a meniscus.
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Bibliography

[1] Kostov, A. & Friedrich, B. (2005). Selection of crucible oxides in molten titanium and titanium aluminium alloys by thermo-chemistry calculation. Journal of Mining and Metallurgy. 41B, 113-125. DOI: 10.2298/JMMB0501113K.
[2] Kuang, J.P., Harding, R.A. & Campbell, J. (2000). Investigation into refractories as crucible and mould materials for melting and casting gamma-TiAl alloys. Materials Science and Technology. 16, 1007-1016. DOI: 10.1179/026708300101508964.
[3] Tetsui, T., Kobayashi, T., Mori, T., Kishimoto, T. & Harada, H. (2010). Evaluation of yttrium applicability as a crucible for induction melting of TiAl alloy. Materials Transactions. 51, 1656-1662. DOI: 10.2320/matertrans.MAW20100.
[4] Myszka, D., Karwiński, A., Leśniewski, W. & Wieliczko, P. (2007). Influence of the type of ceramic moulding materials on the top layer of titanium precision castings. Archives of Foundry Engineering. 7(1), 153-156. DOI: 10.7356/ iod.2015.24.
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[6] Jinjie, G., Jun, J., Yuan, S.L., Guizhong, L., Yanqing, S. & Hongsheng, D. (2000). Evaporation behavior of aluminum during the cold crucible induction skull melting of titanium aluminum alloys. Metallurgical and Materials Transactions B. 31B, 837-844. DOI: 10.1007/s11663-000-0120-1.
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[8] Ivanchenko, V., Ivasishin, G. & Semiatin, S. (2003). Evaluation of evaporation losses during electron-beam melting of Ti-Al-V alloys. Metallurgical and Materials Transactions B. 34B, 911-915. DOI: 10.1007/s11663-003-0097-7.
[9] Su, Y., Guo, J., Jia, J., Liu, G. & Liu, Y. (2002). Composition control of a TiAl melt during the induction skull melting (ISM) process. Journal of Alloys and Compounds. 334, 261-266. DOI: 10.1016/S0925-8388(01)01766-2.
[10] Guo, J., Liu, G., Su, Y., Ding, H., Jia, J. & Fu, H. (2002). The critical pressure and impeding pressure of Al evaporation during induction skull melting processing of TiAl. Metallurgical and Materials Transactions A. 31A, 3249-3253. DOI: 10.1007/s11661-002-0311-2.
[11] Gou, J., Liu, Y., Su, Y., Ding, H., Liu, G. & Jia, J. (2000). Evaporation behaviour of aluminum during the cold crucible induction skull melting of titanium aluminum alloys. Metallurgical and Materials Transactions B. 31B, 837-844. DOI: 10.1007/s11663-000-0120-1.
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[14] Song, J.H., Min, B.T., Kim, J. H., Kim, H.W., Hong, S.W. & Chung, S.H. (2005). An electromagnetic and thermal analysis of a cold crucible melting. International Communications in Heat and Mass Transfer. 32, 1325-1336. DOI: 10.1016/j.icheatmasstransfer.2005.07.015.
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[18] Ward, R.G. (1963). Evaporative losses during vacuum induction melting of steel. Journal of the Iron and Steel Institute. 1, 11-15.
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[21] Ozberk, E. & Guthrie, R. (1986). A kinetic model for the vacuum refining of inductively stirred copper melts. Metallurgical Transactions B. 17, 87-103.
[22] Przyłucki, R., Golak, S., Oleksiak, B. & Blacha, L. (2012). Influence of an induction furnace's electric parameters on mass transfer velocity In the liquid phase. Metalurgija. 1, 67-70.
[23] Blacha, L., Przylucki, R., Golak, S. & Oleksiak, B. (2011). Influence of the geometry of the arrangement inductor - crucible to the velocity of the transport of mass in the liquid metallic phase mixed inductive. Archives of Civil and Mechanical Engineering. 11, 171-179. DOI: 10.1016/S1644-9665(12)60181-2.
[24] Blacha, L., Golak, S., Jakovics, S. & Tucs, A. (2014). Kinetic analysis of aluminum evaporation from Ti-6Al-7Nb. Archives of Metallurgy and Materials. 59, 275-279. DOI: 10.2478/amm-2014-0045
[25] Spitans, S., Jakovics, A., Baake, E. & Nacke, B. (2010). Numerical modelling of free surface dynamics of conductive melt in the induction crucible furnace. Magnetohydrodynamics. 46, 425-436
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Authors and Affiliations

Albert Smalcerz
ORCID: ORCID
Leszek Blacha
ORCID: ORCID
J. Łabaj
1
ORCID: ORCID

  1. Silesian University of Technology, Faculty of Materials Engineering and Metallurgy, ul. Krasińskiego 8, 40-019 Katowice, Poland
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Abstract

In this paper, the results of the study on aluminium evaporation from the Al-Zn alloys (4.2% weight) during remelting in a vacuum induction furnace (VIM) are presented. The evaporation of components of liquid metal alloys is complex due to its heterogeneous nature. Apart from chemical affinity, its speed is determined by the phenomena of mass transport, both in the liquid and gas phase. The experiments were performed at 10-1000 Pa for 953 K - 1103 K. A significant degree of zinc loss has been demonstrated during the analysed process. The relative values of zinc loss ranged from 4 to 92%. Lowering the pressure in the melting system from 1000 Pa to 10 Pa caused an increase in the value of density of the zinc evaporating stream from 3.82⋅10-5 to 0.000564 g⋅cm-2⋅s-1 at 953 K and 3.32⋅10-5 to 0.000421 g⋅cm-2⋅s-1 for 1103 K. Based on the results of the conducted experiments. it was found that evaporation of zinc was largely controlled by mass transfer in the gas phase and only for pressure 10 Pa this process was controlled by combination of both liquid and gas phase mass transfer.
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Bibliography

[1] Guo, J., Liu, Y. & Su, Y. (2002). Evaporation of multi-components in Ti-25Al-25Nb melt during induction skull melting process. Transaction of Nonferrous Metals Society of China. 12(4), 587-591.
[2] Blacha, L., Mizera, J. & Folega, P. (2013). The effects of mass transfer in the liquid phase on the rate of aluminium evaporation from the Ti-6Al-7Nb alloy. Metalurgija, 53(1), 51-54.
[3] HSC Chemistry ver. 6.1. Outocumpu Research Oy. Pori.
[4] Plewa, J. (1987). Examples of calculations from the theory of metallurgical processes. Gliwice: Wydawnictwo Politechniki Śląskiej. (in Polish).
[5] Ozberk, E. & Guthrie, R. (1986). A kinetic model for the vacuum refining of inductively stirred copper melts. Metallurgical Transactions B. 17, 87-103.
[6] Nash, P.M. & Steinemann, S.G. (2006). Density and thermal expansion of molten manganese. Iron. Nickel. Copper. Aluminium and Tin by Means of the Gamma-Ray Attenuation Technique. Physics and Chemistry of Liquids, An International Journal. 29(1), 43-58.
[7] Assael, M., Kakosimos, K. & Banish, R. (2006). Reference data for the density and viscosity of liquid aluminum and liquid iron. Journal of Physical and Chemical Reference Data. 35(1), 285-301.
[8] Smalcerz, A., Węcki B. & Blacha L. (2021) Influence of the power of various types of induction furnaces on the shape of the metal bath surface. Advances in Science and Technology Research Journal. 15(3), 34-42. DOI: 10.12913/22998624/138245
[9] Homma, M., Ohno, R., & Ishida, T. (1996). Evaporation of manganese. copper. and tin from molten iron under, vacuum. Science Reports of the Research Institutes, Tohuku University. Series A – Physics. chemistry and metallurgy. 18, 356-365.
[10] Ohno, R. & Ishida, T. (1967). Solution rate of solid iron in liquid copper, ISIJ International. 31(10), 1164-1169.
[11] Chen, X. & Ito, N. (1995). Evaporation rate of copper in high carbon iron melt under reduced pressure. Tetsu-to-Hagane. 81(10), 959-964.
[12] Savov, L. & Janke, D. (2000). Evaporation of cu and sn from induction-stirred iron-based melts treated at reduced pressure. ISIJ International. 40(2), 95-104.
[13] Łabaj, J. (2012). Kinetics of cooper evaporation from the Fe-Cu Alloys under Reduced Pressure. Archives of Metallurgy and Materials. 57(1), 165-172.
[14] Maruyama, T., Katayama, H., Momono, T., Tayu, Y, & Takenouchi, T. (1998). Evaporation rate of copper from molten iron by urea spraying under reduced pressure. Tetsu-to-Hagane. 84(4), 243-248.
[15] Ono-Nakazato, H. & Taguchi, K. (2003). Effect of silicon and carbon on the evaporation rate of copper in molten iron. ISIJ International. 43(11), 1691-169.
[16] Bellot, J.P., Duval, H., Ritchie, M., Mitchell, A. & Ablitzer, D. (2001). Evaporation of Fe and Cr from induction-stirred austenitic stainless steel-influence of the inert gas pressure, ISIJ International. 41(7), 696-705.
[17] Siwiec, G. (2013). The kinetics of aluminium evaporation from the Ti-6Al-4V alloy. Archives of Metallurgy and Materials. 58(4), 1155-1160.
[18] Blacha, L. Golak, S. Jakovics, S. & Tucs A. (2014) Kinetic analysis of aluminum evaporation from Ti-6Al-7Nb. Archives of Metallurgy and Materials. 59, 275-279. DOI: 10.2478/amm-2014-0045.
[19] Blacha, L., Burdzik, R. Smalcerz, A. & Matuła, T. (2013). Effects of pressure on the kinetics of manganese evaporation from the OT4 alloy. Archives of Metallurgy and Materials. 58(1), 197-201.
[20] Harris, R. (1984). Vacuum refining copper melts to remove bismuth, arsenic and antimony. Metallurgical Transaction B. 15, 251-257.
[21] Harris, R., McClincy, R.J. & Riebling, E.F. (1987). Bismuth, arsenic and antimony removal from anode copper via vacuum distillation. Canadian Metallurgical Quarterly. 26(1), 1-4.
[22] Ozberk, B., Guthire, R.I.L. (1987). Vacuum melting of copper evaporation – evaporation of impurities. Proc. 6th Int. Vacuum Metallurgy Conf. American Vacuum Society. San Diego. 248-267.
[23] Machlin, E.S. (1961). Kinetics of vacuum induction refining – theory. the american institute of mining. Metallurgical. and Petroleum Engineers.
[24] Tarapore, E.D. & Evans, J. (1976). Fluid velocities in induction melting furnaces: Part I. Theory and laboratory experiments. Metallurgical Transaction B. 7, 343-351.
[25] Tarapore, E.D., Evans, J. & Langfeld, J. (1977). Fluid velocities in induction melting furnaces: Part II. large scale measurements and predictions. Metallurgical Transaction B. 8, 179-184.
[26] Szekely, J., Chang, W. & Johnson, W. (1977). Experimental measurement and prediction of melt surface velocities in a 30.000 lb inductively stirred melt. Metallurgical Transaction B. 8, 514-517.
[27] Przyłucki, R. Golak, S. Oleksiak, B. & Blacha L. (2012). Influence of an induction furnace's electric parameters on mass transfer velocity In the liquid phase. Metalurgija. 1, 67-70.
[28] Blacha, L. Przylucki, R. Golak, S. & Oleksiak B. (2011). Influence of the geometry of the arrangement inductor - crucible to the velocity of the transport of mass in the liquid metallic phase mixed inductive. Archives of Civil and Mechanical Engineering. 11, 171-179 DOI: 10.1016/S1644-9665(12)60181-2
[29] Du, Y., Chang, Y., Huang, B., Gong, W. & Jin, Z. (2003). Diffusion coefficients of some solutes in fcc and liquid Al: critical evaluation and correlation. Materials Science and Engineering: A. 363(1-2), 140-151.
[30] Harris, R. & Davenport, W.G. (1982). Vacuum distillation of liquid metals: Part I. Theory and experimental study. Metallurgical Transactions B. 13, 581-588.

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Authors and Affiliations

Albert Smalcerz
ORCID: ORCID
Leszek Blacha
ORCID: ORCID
B. Węcki
1
ORCID: ORCID
D.G. Desisa
2
ORCID: ORCID
J. Łabaj
3
ORCID: ORCID
M. Jodkowski
1
ORCID: ORCID

  1. Department of Testing and Certification "ZETOM", Poland
  2. Department of Industrial, Informatics Silesian University of Technology, Joint Doctorate School, Poland
  3. Faculty of Materials Engineering, Silesian University of Technology, Poland
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Abstract

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 (R 2), 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.
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Authors and Affiliations

Hicham En-nkhili
1
ORCID: ORCID
Imane Nizar
2
ORCID: ORCID
Mohammed Igouzal
1
ORCID: ORCID
Azzeddin Touazit
1
ORCID: ORCID
Nizar Youness
1
ORCID: ORCID
Issam Etebaai
3
ORCID: ORCID

  1. Ibn Tofail University, Faculty of Science, Department of Physics, Laboratory of Electronic Systems, Information Processing, Mechanics and Energy, University campus, B.P. 242, 14000 Kenitra, Morocco
  2. University Hassan II, Higher Normal School of Technical Education (ENSET), Computer Science, Artificial Intelligence and Cybersecurity (IIACS), Mohammedia, Casablanca, Morocco
  3. Abdelmalek Essaadi University, Faculty of Science and Technique, Department of Earth and Environmental Sciences, Team of Applied Geosciences and Geological Engineering, Al Hoceima, Morocco
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Abstract

Beyşehir Lake is the largest freshwater lake in the Mediterranean region of Turkey that is used for drinking and irrigation purposes. The aim of this paper is to examine the potential for data-driven methods to predict long-term lake levels. The surface water level variability was forecast using conventional machine learning models, including autoregressive moving average (ARMA), autoregressive integrated moving average (ARIMA), and seasonal autoregressive integrated moving average (SARIMA). Based on the monthly water levels of Beyşehir Lake from 1992 to 2016, future water levels were predicted up to 24 months in advance. Water level predictions were obtained using conventional time series stochastic models, including autoregressive moving average, autoregressive integrated moving average, and seasonal autoregressive integrated moving average. Using historical records from the same period, prediction models for precipitation and evaporation were also developed. In order to assess the model’s accuracy, statistical performance metrics were applied. The results indicated that the seasonal autoregressive integrated moving average model outperformed all other models for lake level, precipitation, and evaporation prediction. The obtained results suggested the importance of incorporating the seasonality component for climate predictions in the region. The findings of this study demonstrated that simple stochastic models are effective in predicting the temporal evolution of hydrometeorological variables and fluctuations in lake water levels.
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Authors and Affiliations

Remziye I. Tan Kesgin
1
ORCID: ORCID
Ibrahim Demir
2
ORCID: ORCID
Erdal Kesgin
3
ORCID: ORCID
Mohamed Abdelkader
4
ORCID: ORCID
Hayrullah Agaccioglu
2
ORCID: ORCID

  1. Fatih Sultan Mehmet Vakıf University, Faculty of Engineering, Department of Civil Engineering, Beyoglu, 34445, Istanbul, Turkey
  2. Yıldız Technical University, Faculty of Civil Engineering, Department of Civil Engineering, Esenler, 34210, Istanbul, Turkey
  3. Istanbul Technical University, Faculty of Civil Engineering, Department of Civil Engineering, Maslak, 34469, Istanbul, Turkey
  4. Stevens Institute of Technology, Department of Civil, Environmental, and Ocean Engineering, 1 Castle Point Terrace, Hoboken, NJ 07030, USA
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Abstract

The usage of the reduced pressure in the processes of smelting and refining of metal alloys allow to remove not only the gases dissolved in the metal bath, but also the impurities having a higher vapour pressure than the matrix metal. Blister copper produced in flash furnace contains many impurities such as lead, bismuth and arsenic. Some of them must be removed from molten metals, because of their deleterious effects on copper electrical properties. When the smelting process is carried out in the induction vacuum furnaces, the abovementioned phenomenon is being intensified, one or another mixing of bath and increase in the surface area of mass exchange (liquid metal surface). The latter results from the formation of a meniscus being an effect of the electromagnetic field influence on the liquid metal. In the work, the results of refining blister copper in terms of removing lead from it, are presented. The experiments were carried out in the induction crucible vacuum furnace at temperatures of 1473 and 1523 K, and operating pressures in a range of 8 - 533 Pa.

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Authors and Affiliations

Albert Smalcerz
ORCID: ORCID
Leszek Blacha
ORCID: ORCID
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Abstract

Artificial neural network models (ANNs) were used in this study to predict reference evapotranspiration ( ETo) using climatic data from the meteorological station at the test station in Kafr El-Sheikh Governorate as inputs and reference evaporation values computed using the Penman–Monteith (PM) equation. These datasets were used to train and test seven different ANN models that included different combinations of the five diurnal meteorological variables used in this study, namely, maximum and minimum air temperature ( Tmax and Tmin), dew point temperature ( Tdw), wind speed ( u), and precipitation (P), how well artificial neural networks could predict ETo values. A feed- forward multi-layer artificial neural network was used as the optimization algorithm. Using the tansig transfer function, the final architected has a 6-5-1 structure with 6 neurons in the input layer, 5 neurons in the hidden layer, and 1 neuron in the output layer that corresponds to the reference evapotranspiration. The root mean square error ( RMSE) of 0.1295 mm∙day –1 and the correlation coefficient ( r) of 0.996 are estimated by artificial neural network ETo models. When fewer inputs are used, ETo values are affected. When three separate variables were employed, the RMSE test values were 0.379 and 0.411 mm∙day –1 and r values of 0.971 and 0.966, respectively, and when two input variables were used, the RMSE test was 0.595 mm∙day –1 and the r of 0.927. The study found that including the time indicator as an input to all groups increases the prediction of ETo values significantly, and that including the rain factor has no effect on network performance. Then, using the Penman–Monteith method to estimate the missing variables by using the ETo calculator the normalised root mean squared error ( NRMSE) reached about 30% to predict ETo if all data except temperature is calculated, while the NRMSE reached about of 13.6% when used ANN to predict ETo using variables of temperature only.
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Authors and Affiliations

Amal Abo El-Magd
1
ORCID: ORCID
Shaimaa M. Baraka
2
ORCID: ORCID
Samir F.M. Eid
1
ORCID: ORCID

  1. Agricultural Engineering Research Institute (AEnRI), Agricultural Research Centre (ARC) Nadi El-Said St. Dokki, P.O. Box 256, Giza, Egypt
  2. Ain Shams University, Faculty of Agriculture, Department of Agricultural Engineering, Cairo, Egypt

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