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Number of results: 16
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Abstract

Al2O3-Al2TiO5-TiO2 composites can be obtained by the infiltration of molecular titanium precursors into presintered α-Al2O3 (corundum) cylinders. Two titanium tetraalkoxides, and two dialkoxy titanium bis(acetylacetonates) serve as precursors for TiO2 (rutile) and Al2TiO5 (tialite). The precursors were infiltrated as ethanolic solutions. After sintering at 1550, 1600, and 1650°C, the prepared ceramics’ properties were investigated by SEM, in-situ HT-XRD, and conventional XRD. Titanium tetraisopropoxide leads to the highest content of Al2TiO5 in the composite. The more reactive the precursor, considering the Al2O3/precursor interface, the lower and more anisotropic the grain growth, the more homogeneous is the TiO2 contribution and the higher is the content of Al2TiO5. Raising the sintering temperature causes an increase of the crystalline Al2TiO5 con­tent as well as of the grain growth. Moreover, the reactivity of the precursor molecule influences the Ti/(Al + Ti) ratio in the obtained tialite phase.

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Authors and Affiliations

B. Dittert
M. Wiessner
P. Angerer
J.M. Lackner
H. Leichtfried
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Abstract

In the defunct Górka heading there is both a waste disposal site with an area of 6.7 ha containing approximately 600 000 m3 of waste generated in the course of aluminum oxide production and a pond with an area of 3 ha and depth ofup to 15 m containing about 400 000 m3 of effluent (leachate water). The reservoir is filled with infiltrates flowing in from the above-mentioned disposal site at a rate - 130 m3/day. The subsidence of the pond bottom and infiltration of solutions into the Triassic and Jurassic water resources, estimated at - 40 m3/day, is a cause of serious concern. The basic problem of the effluents in the Górka pond is their high alkalinity (pH 12-14) and variable pollutant content, the level of which increases with the pond's depth. The proposed solution involves pumping out and treating about 500 000 m3 of effluents retained in the Górka reservoir. The effluents would be treated in a reverse osmosis plant using a process which has so far been verified on a quarter-commercial scale. The treatment process by-product would be discharged into the Ropa stream. The brine solution (containing - 25% NaCl), would be solidified. The next stage after pumping would be the utilization of approximately 50 000 m3 of bottom slurry. Highly alkaline slurries would be utilized in the production of self-solidifying mixtures. These mixtures would be used to scal the bottom of the Górka reservoir and part of the edges of the defunct quarry, according to requirements. The next stage would involve outcropping the feed-water sources located in the northern section of the old heading to reconstruct the original flow system from the sources to the Ropa River. The excavated solid waste would be relocated into the remainder of the disposal site containing solid aluminium waste. The surface ofthc site would be scaled and then reclaimed. The final stage involves macrolcvclling of the site into an amphitheatre system, outcropping the fertile soil layer, constructing a lake and streams, and finally land reclamation of the whole site.
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Authors and Affiliations

Zygmunt Kowalski
Ryszard Strzelecki
Premysław Wolski
Joanna Kulczycka
ORCID: ORCID
Piotr Rudnicki
Agnieszka Sobczak
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Abstract

Time of concentration, Tc, is defined as time elapsed from the beginning of rainfall infiltrated into soil layer until it reaches a constant infiltration rate (fc) which is indicated an equilibrium subsurface flow rate. In hydrological view, time of concentration plays a significant role in elaboration of transformation of rainfall into runoff in a watershed. The aims of this research are to define influence of soil density and soil water content in determining time of concentration using infiltration concept based on water balance theory, and to find out the effect of land slope this time. Watershed laboratory experiment using rainfall simulator was employed to examine time of concentration associated with infiltration process under different slope, soil density and soil water content based on water balance concept. The steady rainfall intensity was simulated using sprinklers which produced 2 dm3∙min–1. Rainfall, runoff and infiltration analysis were carried out at laboratory experiment on soil media with varied of soil density (d) and soil water content (w), where variation of land slopes (s) were designed in three land slopes 2, 3 and 4%. The results show that relationship between soil density and land slope to time of concentra-tion showed a quadratic positive relationship where the higher the soil density address to the longer time of concentration. Moreover, time of concentration had an inverse relationship with soil water content and land slope that means time of con-centration decreased when the soil water content increased.

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Authors and Affiliations

Donny Harisuseno
Dian Noorvy Khaeruddin
Riyanto Haribowo
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Abstract

This study examined the process of filtering of infiltrated water containing excessive amounts or iron, manganese, and fulvic acids through two filtration beds-sand and zeolite-exhibiting catalytic properties. The fulvic acids that were added to the filtered water were extracted from mud in Kołobrzeg. The zeolite bed was modified with manganese oxide using our own technology and required periodic regeneration using 0.3% KMnO, solution. Our study showed the fulvic acids' negative effect on the process of water purification. The zeolite bed reduces this effect and is more effective than the quartz sand bed.
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Authors and Affiliations

Anna M. Anielak
Mariusz Wojnicz
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Abstract

Infiltration process plays important role in water balance concept particularly in runoff analysis, groundwater re-charged, and water conservation. Hence, increasing knowledge concerning infiltration process becomes essential for water manager to gain an effective solution to water resources problems. This study employed multiple linear regression for esti-mating infiltration rate where the soil properties used as the predictor variable and measured infiltration rate as the response variable. Field measurement was conducted at sixteen points to obtain infiltration rate using double ring infiltrometer and soil properties namely soil porosity, silt, clay, sand content, degree of saturation, and water content. The result showed that measured infiltration rate had an average initial infiltration rate (f0) of 6.92 mm∙min–1 and final infiltration rate (fc) of 1.49 mm∙min–1. Soil porosity and sand content showed a positive correlation with infiltration rate by 0.842, 0.639, respectively, while silt, clay, water content, and degree of saturation exhibited a negative correlation by –0.631, –0.743, –0.66 and –0.49, respectively. Three types of regression equations were established based on type of soil properties used as predictor varia-bles. The model performance analysis was conducted for each equation and the result shows that the equation with five predictor variables fMLR_3 = – 62.014 + 1.142 soil porosity – 0.205 clay, – 0.063 sand – 0.301, silt + 0.07 soil water content with R2 (0.87) and Nash–Sutcliffe (0.998) gave the best result for estimating infiltration rate. The study found that soil po-rosity contributes mostly to the regression equation that indicates great influence in controlling soil infiltration behavior.

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Authors and Affiliations

Donny Harisuseno
ORCID: ORCID
Evi N. Cahya
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Abstract

Microwave Assisted Self-propagating High-temperature Synthesis (MASHS) was used to prepare open-porous MAX phase preforms in Ti-Al-C and Ti-Si-C systems, which were further used as reinforcements for Al-Si matrix composite materials. The pretreatment of substrates was investigated to obtain open-porous cellular structures. Squeeze casting infiltration was chosen to be implemented as a method of composites manufacturing. Process parameters were adjusted in order to avoid oxidation during infiltration and to ensure the proper filling. Obtained materials were reproducible, well saturated and dense, without significant residual porosity or undesired interactions between the constituents. Based on this and the previous work of the authors, the reinforcement effect was characterized and compared for both systems. For the Al-Si+Ti-Al-C composite, an approx. 4-fold increase in hardness and instrumental Young's modulus was observed in relation to the matrix material. Compared to the matrix, Al-Si+Ti-Si-C composite improved more than 5-fold in hardness and almost 6-fold in Young's modulus. Wear resistance (established for different loads: 0.1, 0.2 and 0.5 MPa) for Al-Si+Ti-Al-C was two times higher than for the sole matrix, while for Al-Si+Ti-Si-C the improvement was up to 32%. Both composite materials exhibited approximately two times lower thermal expansion coefficients than the matrix, resulting in enhanced dimensional stability.
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Bibliography

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Authors and Affiliations

A. Dmitruk
1
ORCID: ORCID
K. Naplocha
1
ORCID: ORCID
A. Żak
2
A. Strojny-Nędza
3

  1. Wrocław University of Science and Technology, Faculty of Mechanical Engineering, Department of Lightweight Elements Engineering, Foundry and Automation, Poland
  2. Wrocław University of Science and Technology, Faculty of Chemistry, Institute of Advanced Materials, Poland
  3. Łukasiewicz Institute of Microelectronics and Photonics, Poland
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Abstract

In this study, a pilot-scale subsurface wastewater infiltration system (SWIS) was deployed to study landscape water treatment. The goal of the study was to investigate the effects of hydraulic loading on pollutant removal and the spatial distribution of biofilm properties in SWIS. Results showed that the efficiencies of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) removal degraded as hydraulic loading increased. Furthermore, quantities of the biofilm properties parameter s increased with the hydraulic loading. Polysaccharide and protein levels ranged from 560 to 1110 μg/g filler and 60 to 190 μg/g filler, respectively, at a hydraulic loading of 0.2 m/d. At a hydraulic loading of 0.4 m/d, the quantities of polysaccharide and protein ranged from 1200 to 3300 μg/g filler and 80 to 290 μg/g filler, respectively. Biofilm intensity and biofilm activity per unit weight decreased with the increase in hydraulic loading.

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Authors and Affiliations

Liangbo Zhang
Jian Yang
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Abstract

The paper presents a detailed description of one of the newest methods of vacuum saturation of reinforcing preforms in gypsum molds. As an appropriate selection of the infiltration time is a crucial problem during realization of this process, aim of the analysis shown in the paper is to present methods of selection of subatmospheric pressure application time, a sequence of lowering and increasing pressure, as well as examining influence of structure of reinforcing preforms on efficiency of this process. To realize the aim, studies on infiltration of reinforcing preforms made of a corundum sinter of various granulation of sintered particles with a model alloy were conducted. The infiltration process analysis was carried out in two stages. The first stage consisted in investigation of influence of lengthening of sucking off air from the reinforcing preforms on efficiency of this process. In the second stage, an analysis of influence of a two-staged infiltration process on saturation of the studied materials was conducted. Because the studied preforms were of similar porosity, the obtained differences of the saturation level of particular preforms have shown, that the saturation process is influenced mostly by size of pores present in the reinforcement. Because of these differences, each reinforcement type requires individual selection of time and sequence of the saturation process. For reinforcements of higher pore diameter, it is sufficient to simply increase air sucking off time to improve the saturation, while for reinforcement of smaller pore diameter, it is a better solution to apply the two-staged process of sucking off air. Application of the proposed analysis method allows not only obtaining composite castings of higher quality, but also economical optimization of the whole process.

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Authors and Affiliations

K. Gawdzińska
D. Nagolska
P. Szymański
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Abstract

Ceramic injection moulding and gas pressure infiltration were employed for the manufacturing of alumina/AlSi10Mg composites. Porous ceramic preforms were prepared by mixing alumina powder with a multi-binder system and injection moulding of the powder polymer slurry. Then, the organic part was removed through a combination of solvent and thermal debinding, and the materials were finally sintered at different temperatures. The ceramic preforms manufactured in this way were infiltrated by an AlSi10Mg alloy. The microstructure and properties of the manufactured materials were examined using scanning electron microscopy, mercury porosimetry and bending strength testing. The results of transmission electron microscopy and scanning electron microscopy observations show that the fabricated composite materials are characterised by the percolation type of the microstructure and a lack of unfilled pores with good cohesion at the metal-ceramic interfaces. This is surprising considering that over 30% of the pores are smaller than 1 μm. The results show that the bending strength of the obtained composites decreased with increasing sintering temperature of the porous preforms.

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Authors and Affiliations

G. Matula
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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
ORCID: ORCID
Fouad Elfettahi
2
Hajar Griou
1
ORCID: ORCID
Mohammed Y. El Brouzi
3
Mohammed Aboulouafa
1
ORCID: ORCID
Said Ibn Ahmed
1

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

In recent years, a growing problem of water deficit has been observed, which is particularly acute for agriculture. To alleviate the effects of drought, hydrogel soil additives – superabsorbent polymers (SAPs) – can be helpful.
The primary objective of this article was to present a comparison of the advantages resulting from the application of synthetic or natural hydrogels in agriculture. The analysis of the subject was carried out based on 129 articles published between 1992 and 2020. In the article, the advantages of the application of hydrogel products in order to improve soil quality, and crop growth.
Both kinds of soil amendments (synthetic and natural) similarly improve the yield of crops. In the case of natural origin polymers, a lower cost of preparation and a shorter time of biodegradation are indicated as the main advantage in comparison to synthetic polymers, and greater security for the environment.
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Authors and Affiliations

Beata Grabowska-Polanowska
1
ORCID: ORCID
Tomasz Garbowski
1
ORCID: ORCID
Dominika Bar-Michalczyk
1
ORCID: ORCID
Agnieszka Kowalczyk
1
ORCID: ORCID

  1. Institute of Technology and Life Sciences – National Research Institute, Falenty, Hrabska Av. 3, 09-090 Raszyn, Poland
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Abstract

The presented studies focus on changes in groundwater levels and chemistry, and the identification of important factors influencing these changes on short- and long-term scales in urban areas. The results may be useful for rational and sustainable groundwater planning and management in cities. The studies concerned three aquifers: (1) the shallow Quaternary aquifer, (2) the deep Quaternary aquifer, and (3) the Oligocene aquifer in the capital city of Warsaw (Poland). The spatial variability of groundwater recharge was determined and its changes in time were characterized. The characteristics of groundwater levels were based on long-term monitoring series. The results indicate that urban development has caused overall reduction in infiltration recharge (from 54 to 51 mm/ year), which is particularly clear in the city suburbs and in its centre, where land development has significantly densified during the last 30 years. Studies of groundwater levels indicate variable long-term trends. However, for the shallowest aquifer, the trends indicate a gradual decrease of the groundwater levels. In the case of the much deeper Oligocene aquifer, groundwater table rise is observed since the 1970s (averagely c. 20 m), which is related with excessive pumping. Based on the studied results, the groundwater chemistry in the subsurface aquifer indicates strong anthropogenic influence, which is reflected in multi-ionic hydrogeochemical types and the occurrence of chemical tracers typical of human activity. The Oligocene aquifer is characterized by a chemical composition indicating the influence of geogenic factors.
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Authors and Affiliations

Ewa Krogulec
1
Tomasz Gruszczyński
1
Sebastian Kowalczyk
1
Jerzy J. Małecki
1
Radosław Mieszkowski
1
ORCID: ORCID
Dorota Porowska
1
Katarzyna Sawicka
1
Joanna Trzeciak
1
Anna Wojdalska
1
Sebastian Zabłocki
1
Daniel Zaszewski
1
ORCID: ORCID

  1. University of Warsaw, Faculty of Geology, Żwirki i Wigury 93, 02-089 Warszawa, Poland
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Abstract

Wider application of silicon carbide (SiC) is anticipated for increasing the durability of various structural facilities. For this study, SiC was fabricated with decreased electrical resistivity for precision electrical discharge machining. Two-step reaction sintering by infiltration of molten Fe-Si alloy was applied for SiC fabrication. The procedure included first sintering at 973 K in Ar gas atmosphere and second sintering by spontaneous infiltration of molten Fe-75%Si alloy at 1693 K in vacuum. The sintered structure porosity became very low, forming 3C-type SiC. Results confirmed that molten Fe-75%Si alloy infiltration occurred because of reaction sintering. The electrical resistivity of the sintered SiC infiltrated by molten Fe-75%Si alloy can be improved to be two orders of magnitude lower than that by molten Si, consequently maintaining the high performance of SiC.

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Authors and Affiliations

Yoshitsugu Hanada
Yang Xiao
Akio Sonoda
Hyo-Gyoung Kang
Hideaki Nagayoshi
Atsuo Yamamoto
Tatsuya Tokunaga
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Abstract

The objective of this experimental study was to examine whether an assisting layer of lightweight expanded clay aggregate (LECA) of the granulation 1–4 mm, introduced into a subsoil, is able to improve an efficiency of removal of total nitrogen and total phosphorus from domestic wastewater. In the investigations, an assisting 0.10 and 0.20 m thick LECA layer was applied. It has been observed that the effectiveness of removal of total suspended solids (TSS), total nitrogen and total phosphorus from wastewater as well as the level of biochemical oxygen demand ( BOD 5) and chemical oxygen demand ( COD) is in accordance with the Polish standards on wastewater disposal into grounds and surface water. The performed experiments showed that the effectiveness of raw wastewater purification for the medium sand soil bed with the 0.20 m thick assisting LECA layer is higher than for the 0.10 m thick assisting layer. In the medium sand soil bed with the 0.20 m thick assisting LECA layer, the removal efficiency regarding total nitrogen increased by 20.6%, total phosphorus by 5.2%, ammonium nitrogen by 8.8% and TSS by 5.3%, and reduction efficiency regarding BOD 5 increased by 1.7% and COD by 2.3% with relation to the 0.10 m thick assisting LECA layer (all percentages – in average). The results of the experiment showed that the LECA with the granulation 1–4 mm can be used to assist in removal of total nitrogen and total phosphorus from wastewater with application of infiltration drainage.
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Authors and Affiliations

Marek Kalenik
1
ORCID: ORCID
Piotr Wichowski
1
ORCID: ORCID
Marek Chalecki
2
ORCID: ORCID
Adam Kiczko
1
ORCID: ORCID

  1. Warsaw University of Life Sciences – SGGW, Institute of Environmental Engineering, Department of Hydraulics and Sanitary Engineering, Nowoursynowska 159, 02-776 Warsaw, Poland
  2. Warsaw University of Life Sciences – SGGW, Institute of Civil Engineering, Department of Mechanics and Building Structures, Warsaw, Poland

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