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Impact of raw and purified wastewater reuse from the Dar El-Gueddari treatment plant on the soil

Smail Njimat Fouad Elfettahi Hajar Griou Mohammed Y. El Brouzi Mohammed Aboulouafa Said Ibn Ahmed

Journal of Water and Land Development | 2021 | No 49 | 121-128 | DOI: 10.24425/jwld.2021.137104

Keywords dilutions electrical conductivity infiltration organic matter pH treatment plant wastewater irrigation

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Abstract

The study has been carried out at two experimental sites. It aims to assess the impact of the reuse of raw wastewater, purified and diluted with conventional water on the physicochemical quality of soils compared to irrigated soils with con-ventional drilled water and non-irrigated soil. The obtained results show that the electrical conductivity EC and sodium gradually increase in all the plots irrigated with wastewater. Additionally, a slight increase in the pH levels at the first site and a slight decrease in the second site was seen, but at both sites the soils remained alkaline. The infiltration rate of water slide decreases in relation to the amount of irrigation, especially in plots irrigated by raw and treated wastewater. For the same plots, the values of organic matter increased, and the values obtained for the exchangeable sodium percentage (ESP) became high in the third year and reached 17.0% and 16.7% respectively.

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Authors and Affiliations

Smail Njimat

1

e-mail:

ORCID:

Fouad Elfettahi

2

Hajar Griou

1

e-mail:

ORCID:

Mohammed Y. El Brouzi

3

Mohammed Aboulouafa

1

e-mail:

ORCID:

Said Ibn Ahmed

1

Laboratory of Materials, Electrochemistry and Environment, University Ibn Tofail, Faculty of Sciences, Department of Chemistry, 14200, Kenitra, Morocco
Agricultural Technical Institute, Ain Taoujdate, El Hajeb, Morocco
Laboratory of Genetics, Neuroendocrinobiology and Biotechnology. Faculty of Sciences, Department of Biology

Characterization of High Pressure Water Descaling Jets for Slabs Based on Different Shape Factors

Bowen Yang Guangqiang Liu Chengcheng Xu Kun Liu Peng Han

Archives of Foundry Engineering | 2024 | vol. 24 | No 1 | 121-128 | DOI: 10.24425/afe.2024.149259

Keywords High pressure water Descaling nozzle External jet Conical grooving

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Abstract

The surface temperature of steel billets during hot rolling can reach up to 1200 °C. High temperature promotes rapid oxidation of the surface of steel billets, forming a dense oxide layer similar to fish scales. If not removed in a timely manner, it will damage the surface of the steel billets and exacerbate the wear of the rolls during the descaling process. There are many methods for descaling, but high-pressure water jet has become the main method for descaling due to its excellent descaling performance, low cost, and ease of use. The tip of the descaling nozzle serves as the main component, and its structural parameters affect the final descaling effect. This research changes the shape factor of the nozzle groove curve and the diameter of the nozzle throat, and performs computational fluid dynamics (CFD) simulations on the simplified nozzle external flow field. The axial velocity at the center of the jet generates a velocity peak at 0.5-1 Dc. The peak velocity increases with the increase of shape factor and throat diameter, and the influence of shape factor on the peak velocity is greater. For a constant target distance, the length of the velocity stable section along the jet impact line increases with the increase of the shape factor. The maximum value of dynamic pressure increases, and the smaller the target distance, the greater the dynamic pressure difference. The trend of water volume is roughly the same as that of dynamic pressure.

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Bibliography

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Authors and Affiliations

Bowen Yang

1

Guangqiang Liu

2

Chengcheng Xu

3

Kun Liu

1

e-mail:

ORCID:

Peng Han

1

School of Materials and Metallurgy, University of Science and Technology Liaoning, China
School of Civil Engineering, University of Science and Technology Liaoning, China
Cold Rolling Mill Plant, ANGANG Steel Company Limited, China

Low-Frequency Sound Absorption Potential of Subwavelength Absorbers Based on Coupled Micro-Slit Panels

Yujie Qian Zhengyuan Gao Jie Zhang

Archives of Acoustics | 2024 | vol. 49 | No 1 | 121-128 | DOI: 10.24425/aoa.2024.148766

Keywords coupled MSP (CMSP) cavity-depth optimal scheme (COS) panel thickness optimal scheme (TOS) low frequency absorption performance

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Abstract

Due to space limitations during installation, reducing low-frequency noise has always been a challenging area. Sub-wavelength structures are typically favored in such scenarios for noise reduction. This paper explores the potential of micro-slit panels (MSP) for low-frequency sound absorption. To further optimize the panel thickness, coupled MSPs (CMSP) with a distance between two MSPs of less than 1 mm are proposed. Firstly, the low-frequency absorption performances of a single MSP based on two optimized schemes – the cavity-depth optimal scheme (COS) and the panel thickness optimal scheme (TOS) – are examined and compared with those of existing ultrathin metamaterials. The results demonstrate that MSP has significant potential for low frequency sound absorption, and COS allows for a smaller overall structural thickness but a larger panel thickness than TOS. Secondly, to reduce the panel thickness, the CMSP is developed and the theoretical model of its acoustic impedance is established and validated by experiments. Then, based on the theoretical model, the low-frequency absorption potential of CMSP is optimized using COS. The results show that both the overall thickness and the panel thickness of the CMSP absorber are reduced while maintaining better performance. Furthermore, the proposed absorber achieves a subwavelength scale since its total thickness can be as small as 0.138λ.

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Authors and Affiliations

Yujie Qian

1

Zhengyuan Gao

1

Jie Zhang

1

College of Information Science and Engineering, Hohai University Changzhou, China

Intra-individual variability of dental enamel δ13C and δ18O values in Late Pleistocene cave hyena and cave bear from Perspektywiczna Cave (southern Poland)

Michał Czernielewski Magdalena Krajcarz Maciej T. Krajcarz

Studia Quaternaria | 2020 | vol. 37 | Iss. 2 | 121-128 | DOI: 10.24425/sq.2020.133756

Keywords Pleistocene MIS 3 stable isotopes Perspektywiczna Cave Kraków-Częstochowa Upland

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Abstract

An important source of palaeoecological and palaeoenvironmental information is intra-specimen variability of isotopic composition of mammal tooth enamel. It reflects seasonal or behavioral changes in diet and climate occurring during a life of the animal. While well-known in ungulates, in carnivorans this variability is poorly recognized. However, carnivoran remains are amongst the most numerous in the Pleistocene fossil record of terrestrial mammals, so their isotopic signature should be of particular interest. The aim of the study was to verify if enamel of a fossil cave hyena (Crocuta crocuta spelaea) and a cave bear (Ursus ingressus) records any regular inter- or intra-tooth isotopic variability. We examined intra-individual variability of δ13C and δ18O values in permanent cheek teeth enamel of fossil cave hyena and cave bear from the site of the Perspektywiczna Cave (southern Poland). We conclude that the isotopic variability of the cave hyena is low, possibly because enamel mineralization took place when the animals still relied on a uniform milk diet. Only the lowermost parts of P3 and P4 enamel record a shift toward an adult diet. In the case of the cave bear, the sequence of enamel formation records periodic isotopic changes, possibly correlating with the first seasons of the animal life.

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