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Number of results: 59
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Abstract

The article presents the practical use of biological and hydrological processes (eco-hydrology) for improving the quality of water in the ponds of the Julianowski Park. It also presents an effective method of zoning the park area for new investments.

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Authors and Affiliations

Barbara Wycichowska
Keywords krill ice zone
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Abstract

In the investigated area the overall abundance of krill was small and was increasing with the distance from ice. However, with the data available, it was not possible to decide whether this increase was related to the ice border or was a part of a larger scale phenomenon. The depth distributions as well as the mean values of krill depth were similar to those of open water both in this study and reported in literature.

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Authors and Affiliations

Małgorzata Godlewska
Zygmunt Klusek
Leszek Kamionka
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Abstract

The objective of this study was an analysis of the thickness of a plasticized zone that appears after surface burnishing of machine parts with a non-deformable roller of a torus contour. A function defining the plasticized zone thickness depending on burnishing parameters was determined. M. T. Huber's hypothesis of plastic deformation was used in the solution. It was found that the thickness of the plasticized zone depends principally on the pressure force and yield point, and it is insignificantly dependent on the geometrical dimensions of the workpiece and burnishing roller.
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Authors and Affiliations

Józef Jezierski
Tomasz Mazur
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Abstract

The highest concentrations of algal cells (1.1 x l0 6 litre- 1 ) and of algal carbon (20 μg litre -1 ) were associated with a lens of ice melt water in the northeast of the study area. Phytoflagellates were dominant at all stations with greater numbers always in the 0 - 20 m surface layer and with the peaks of Cryptophyceae in the open waters and also near the ice edge east of 50° W. Picoplankton flagellates and monads (1.5-5.0 μ) were generally next in abundance and most important numerically in the near ice stations in the western part of the study area. Parasinophyceae were usually more abundant than Nitzschia cylindrus (Grunow) Hasle, the only common diatom species found mainly in the western near ice edge stations. The presence olN.cylindrus, dominant in the pack ice and in phytoplankton near the ice edge, shows that algae released from ice may act as an inoculum for the phytoplankton.

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Authors and Affiliations

Elżbieta Kopczyńska
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Abstract

Quantitative data on meiobenthos distribution in four biotopes of the intertidal zone are presented. Differences in taxonomic composition and meiofauna abundance are influenced by the morphology of beaches and their sediment structure.

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Authors and Affiliations

Vadim O. Mokievsky
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Abstract

Results of an oceanographic survey along the edge of drifting pack ice in the area between Elephant Island and the South Orkney Islands are reported. The influence of sea ice on hydrological factors was very weak. It was not possible to develop oceanographic features characteristic for marginal sea-ice zones in the areas with well marked surface currents and dynamic hydrological conditions. The spatial distribution of chlorophyll was governed by water stability, although during our survey, areas with enhanced vertical stability could not be described in terms of a sea-ice edge influence.

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Authors and Affiliations

Maciej Lipski
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Abstract

Water is essential for plant growth and development, and the degree of its availability significantly shapes ecosystems in different climate zones. How does an overabundance or deficiency of water affect the flora in Poland and different parts of the world?

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Authors and Affiliations

Marcin K. Dyderski
Sonia Paź-Dyderska
Andrzej M. Jagodziński

Abstract

The aim of this study is to determine natural and anthropogenic threats and their effects concerning the lakes situated within the coastal zone of the southern Baltic. The shore zone is a place of contact of the sea waters and the inland waters. This results in the formation of special water relationships and special circulation water. Macroscale conditions overlap local hydrological conditions and morphometric features of basins and hydrological features of catchments specific to particular lakes. All the natural conditions have been affected by human activity for over eight centuries. As a result. numerous natural and anthropogenic threats occur and cause not only periodic changes in the structure of lakes but such that even endanger their existence.
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Abstract

Nozzle clogging seriously affects the continuity of spraying powder in vacuum induction melting gas atomization (VIGA) process and increases the consumption of gas and raw materials. However, there are few systematic studies on nozzle clogging. This paper reports the physics of nozzle clogging in gas atomization production. The influence of coupling-length of different melt delivery-tubes on nozzle clogging is studied numerically and experimentally. The interface tracking method of Volume of Fluid (VOF) and the large eddy simulation (LES) model are performed for visualizing the melt droplets flow traces in primary atomization and the associated simulation cloud images compared with experimental results. Four delivery-tube coupling-lengths (0 mm, 3 mm, 5 mm, and 7 mm) relative to nozzle position and two gas pressures (3 MPa and 4.5 MPa) are chosen for this study. The results indicated that the coupling-lengths of 0 mm and 3 mm increases the strength of the recirculation zone, the melt droplets backflow is obvious, and the nozzle is blocked. However, this phenomenon eliminated with increasing coupling-lengths, the atomization process is continuous, but the final fine powder yield decreases. This research is of guiding significance and reference for understanding the nozzle clogging of vacuum induction melting gas atomization (VIGA) technology.
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Authors and Affiliations

Junfeng Wang
1
ORCID: ORCID
Min Xia
1
ORCID: ORCID
Jialun Wu
1
ORCID: ORCID
Changchun Ge
2
ORCID: ORCID

  1. University of Science & Technology Beijing Institute of Special Ceramics and Powder Metallurgy, 30 Xueyuan Road, Haidian District, Beijing,100083, China
  2. University of Science & Technology Academician of CAS, Institute of Special Ceramics and Powder Metallurgy, Beijing, China
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Abstract

The article presents a methodology for determining the value of the expansion coefficient of a reconsolidated caving zone in the context of forecasting the rise in underground mine water levels and consequent surface subsidence caused by the process of flooding the closed coal mines. The paper also provides a brief characterisation of analytical predictive models regarding surface subsidence during the process of flooding coal mines. In order to describe the vertical deformation of the reconsolidated porous rock mass in the caving zone, a linear-elastic medium of Biot was utilised. The conducted theoretical calculations demonstrate a high agreement with the results obtained through the identification of the expansion coefficient parameter based on the analysis of in-situ subsidence measurements in Dutch and German mining areas. The proposed methodology was applied to a real case study involving the forecasting of the impact of the flooding process on the underground workings of the German Ibbenbüren mine. The article constitutes a significant contribution to the field of forecasting the rise in underground mine water levels and surface subsidence during the process of flooding closed coal mines. The presented methodology and obtained results can be valuable for researchers, engineers, and decision-makers involved in the planning and management of mining areas.
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Authors and Affiliations

Rafał Misa
1
ORCID: ORCID
Mateusz Dudek
1
ORCID: ORCID
Anton Sroka
1
ORCID: ORCID
Krzysztof Tajduś
2
ORCID: ORCID
Dawid Mrocheń
1
ORCID: ORCID

  1. Strata Mechanics Research Institute, Polish Academy of Science, Krakow, Poland
  2. AGH University of Science and Technology, Krakow, Poland
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Abstract

In civil engineering, underground structures are exposed to various georisks and require greater attention and awareness of the need to identify them at the earliest possible stage of investment preparation and implementation. The assessment of the interaction of objects in the underground space is a task that requires the analysis of many influencing factors resulting from the geometry and characteristics of the constructed structure and existing buildings, in the context of soil and water conditions. The correctness of such an assessment and forecast of the range and scope of these impacts requires knowledge of both construction and geotechnical issues, as well as knowledge of using the experience gained, including the analysis of the results of observations and monitoring measurements. One of the main challenges associated with underground constructions is their impact on existing buildings and other structures adjacent to the developed site. As these structures are often highly susceptible to excavation-induced ground movements, their behavior have to be considered in a design as one of the geotechnical-related limit states. As in the analysis of limit states, various computational models can be used to assess the impact of investments, including analytical, semi-empirical or numerical models. In the process of assessing the impact of underground structures, it is also important to identify additional elements of potential georisks, e.g. the impact of accompanying works, which in certain situations may have a significant impact on the construction process, requiring preventive measures. On a few examples from the construction of deep excavations and tunnels in different soil and water conditions, the article discusses the aspects of the role of the accuracy of the identification of soil and water conditions and the creation of a reliable and useful subsoil model as elements allowing for the identification and minimization of georisks and its proper management.
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Authors and Affiliations

Tomasz Godlewski
1
ORCID: ORCID
Eugeniusz Koda
2
ORCID: ORCID
Monika Mitew-Czajewska
3
ORCID: ORCID
Stanisław Łukasik
1
ORCID: ORCID
Simon Rabarijoely
2
ORCID: ORCID

  1. Building Research Institute, 21 Ksawerów St., 02-656 Warsaw, Poland
  2. Institute of Civil Engineering, Warsaw University of Life Sciences – SGGW, 159 Nowoursynowska St., 02-776 Warsaw, Poland
  3. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw, Poland
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Abstract

The Kuroshio Extension front (KEF) considerably influences the underwater acoustic environment; however, a knowledge gap persists regarding the acoustic predictions under the ocean front environment. This study utilized the high-resolution ocean reanalysis data (JCOPE2M, 1993–2022) to assess the impact of the KEF on the underwater acoustic environment. Oceanographic factors were extracted from the database using the Douglas-Peucker algorithm, and acoustic propagation characteristics were obtained using the Bellhop raytracing model. This study employed a backpropagation neural network to predict the acoustic propagation affected by the KEF. The depth of the acoustic channel axis and the vertical gradient of the transition layer of sound speed were identified as the fundamental factors influencing the first area of convergence, with correlations between the former and the distance of the first convergence zone ranging from 0.52 to 0.82, and that for the latter ranging from −0.42 to −0.7. The proposed method demonstrated efficacy in forecasting first convergence zone distances, predicting distances with less than 3 km error in >90% of cases and less than 1 km error in 68.61% of cases. Thus, this study provides a valuable predictive tool for studying underwater acoustic propagation in ocean front environments and informs further research.
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Authors and Affiliations

Weishuai Xu
1
Lei Zhang
2
Hua Wang
2

  1. No. 5 Student Team, Dalian Naval Academy Dalian, Liaoning, China
  2. Department of Military Oceanography and Hydrography and Cartography Dalian Naval Academy Dalian, Liaoning, China
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Abstract

During the past quarter of a century, the neglected, post-industrial waterfront of New York has been transformed into lively parks, playgrounds, sports facilities and promenades. Bicycle and pedestrian routes have been built along wharfs, opening them to the public, while the banks of the East River have been connected by the local, highly popular ferries. This paper discusses the history, mechanisms and consequences of this process, the foundations of which were a skilful policy of the city authorities and proper use of urban planning tools.
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Bibliography

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Bauman, Z. (2006.), Płynna nowoczesność, Kraków: Wydawnictwo Literackie.
Bloomberg, M. (The City Of New York Mayor) (2007), PlaNYC: A Greener, Greater New York, New York.
Castells, M. (2007), Siła tożsamości, Warszawa: Wydawnictwo Naukowe PWN.
CURBED, A guide to the major megaprojects transforming New York City, updated Oct 23, 2019, https://ny.curbed.com/maps/nyc-new-development-hudson-yards-wtc-megaprojects, (dostępne/accessed: 15.07.2021).
Jasiński, A. ‘The Newest Genre of New York Skyscrapers: Supertall, Superslim and… Residential’ / ‘Najnowsza generacja nowojorskich wysokościowców: superwysokie, supersmukłe i… mieszkalne’, Przestrzeń i Forma, 28_2016, Szczecin: PAN Oddział w Gdańsku i Zachodniopomorski Uniwersytet Techniczny.
Kosiński, W. ‘Serce świata — Manhattan’, Czasopismo Techniczne Architektura, 2008, nr 3A.
Libeskind, D. (2004), Breaking Ground, New York: Riverhead Books; polskie wydanie: Przełom: przygody w życiu i architekturze (2008), Warszawa: Wydawnictwo Naukowo Techniczne.
NYC Lower Manhattan Coastal Resiliency, Reducing Flood Risk and Building Resilience in Lower Manhattan, New York, 2019, https://www1.nyc.gov/site/lmcr/index.page, (dostępne/accessed: 15.07.2021).
NYC Department of City Planning, New York City Comprehensive Waterfront Plan. Reclaiming the City’s Edge, New York, 1992, https://www1.nyc.gov/assets/planning/download/pdf/about/publications/cwp.pdf, (dostępne/accessed: 15.07.2021).
NYC Department of City Planning, Zoning Handbook 2011 Edition, New York, 2011a. NYC Department of City Planning, Vision 2020.
New York City Comprehensive Waterfront Plan, New York, 2011b, https://www1.nyc.gov/assets/planning/download/pdf/plans-studies/vision-2020-cwp/vision2020/vision2020_nyc_cwp.pdf, (dostępne/accessed: 15.07.2021).
NYC Planning, 2021, New York City Comprehensive Waterfront Plan, Draft Goals and Strategies, Document for Public Discussion, April 2021, https://static1.squarespace.com/static/5ef0c82bd1b5db4d3c1d9507/t/60930b68a94b2351eb1eff64/1620249448705/DraftGoalsStrategies.pdf,
NY State Department of Transportation, The New York State Bicycle and Pedestrian Plan, New York, 1997, https://www.dot.ny.gov/display/programs/bicycle/maps/app_repository/bike_and_ped_plan.pdf, (dostępne/accessed: 15.07.2021).
NY State Department of Transportation, Cycling in the City. Cycling Trends in NYC, New York, 2019, https://www1.nyc.gov/html/dot/downloads/pdf/cycling-in-the-city.pdf, (dostępne/accessed: 15.07.2021).
Quirk, V. ‘The Big U; BIG’s New York City Vision for »Rebuilding by Design«’, ARCHDAILY, April 04, 2014, https://www.archdaily.com/493406/the-big-u-big-s-new-york-city-vision-for-rebuild-by-design, (dostępne/accessed: 15.07.2021).


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Authors and Affiliations

Artur Jasiński
1
ORCID: ORCID

  1. Andrzej Frycz Modrzewski Krakow University, Departament of Architecture and Fine Arts
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Abstract

The development and urban planning affects the general spatial order. Continuously increasing chaos is caused, among other thing, by granting construction permit based on Zoning and Land Use decision. It’s one of the reason why communes do not pass Area Development Plans. Presented research determines the exact reasons this phenomenon. The article also analyses, based on case studies, the unlawful, unsupervised adoption of Zoning and Land Use decisions.

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Authors and Affiliations

Elżbieta Czekiel-Świtalska
Alicja Świtalska
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Abstract

Surface phytoplankton samples were studied quantitatively and qualitatively in February 1996 - November 1998 and January 2003 - November 2005 at the shore and in the center of Admiralty Bay, King George Island. Phytoplankton assemblages showed spring-summer peaks (maxima 4.0-5.2×106 cells l-1) associated with small variations in low atmospheric pressure, and low velocity winds. They were dominated by nano-sized (<20 µm) flagellates and picoplankton (~2 µm). The prevalent nanoflagellates were either Prasinophyceae, Cryptophyceae, or Prymnesiophyceae. Diatoms were next in abundance. Of the seven spring-summer diatom blooms, five had initiated at the shore (maximum 9.8×105 cells l-1; November 1998). They were significantly greater than in the open water, and did not spread into the bay centre. Two observed open water blooms did not reach the shore. Diatoms formed up to 44% of the total cells in the period 1996-98; they only formed <5% in 2003-05. Shore and open water populations differed by diatom dominance structure. Pennates (Fragilariopsis spp., F. cylindrus, Pseudo-nitzschia spp.), and benthic species were prevalent at the shore; centrics (Thalassiosira spp., Chaetoceros socialis) were most common offshore. In 2003-05 diatoms were relatively impoverished in Chaetoceros spp. and the larger (>20 µm) Fragilariopsis spp. Nano-sized Thalassiosira spp. were the winter dominants. Diatom species dominance structure may change at each of the two sites within a month (e.g. shore site: F. cylindrus dominant in October ’98; T. gravida in November ’98). Dinoflagellates showed summer increases associated with diatom blooms. Variations in phytoplankton cell concentrations, the species structures between the shore and open waters, and between seasons appear to be related to physical factors: changes in wind velocity and direction, inflow of waters from the Bransfield Strait, ice melting and changes in atmospheric pressure.

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Authors and Affiliations

Elżbieta E. Kopczyńska
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Abstract

Four water masses were distinguished in the upper water layer between Elephant Island and the South Orkneys. Measurements of temperature, salinity, concentrations of dissolved oxygen and silicates were used for the analysis of the hydrological situation and to recognise the origin of water masses. For additional information, nitrates and chlorophyll concentrations were used. Drake Passage and Bransfield Strait waters occupied the western part of the investigated area, from surface to 150 m depth. Below, the Circumpolar Warm Deep Waters (CWDW) were found. The region east of 53.5°W was occupied by winter Weddell Sea water. Above this, a 45 m thin layer of summer modification of Weddell Sea Surface Water was found between 49°W and the South Orkneys. The highestchlorophyll α concentrations were found in this modified water.

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Authors and Affiliations

Ryszard Tokarczyk
Maciej Lipski
Felix F. Perez
Ricardo P. Reboredo
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Abstract

The research on deformation zoning mechanism of tunnel surrounding rock is of great significance for ensuring safe production and disaster prevention in coal mines. However, the traditional deformation zoning theory of tunnel surrounding rock uses the ideal strain softening model as the criterion for judging the zoning type of all tunnel surrounding rock, ignoring the difference between the deformation zoning type of a specific actual tunnel and the basic zoning type of surrounding rock. In order to study the method for determining the actual deformation zoning type of tunnel surrounding rock, the formation mechanism of the actual deformation zoning of tunnel surrounding rock has been revealed. Combined with engineering examples, a method for determining the actual deformation zoning type and boundary stress of specific tunnel surrounding rock has been proposed. The results show that the boundary stress and position of the actual deformation zone are determined by the peak strength fitting line, residual strength fitting line, support strength line, and the position of the circumferential and radial stress relationship lines of each deformation zone. The actual boundary stress of each zone of tunnel surrounding rock is ultimately only related to the basic mechanical properties of the tunnel surrounding rock and the in-situ stress field. The research results can provide reference for disaster management of underground engineering, stability evaluation of surrounding rock, and support scheme design.
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Authors and Affiliations

Wei Jing
1
ORCID: ORCID
Yunlong Gao
2
ORCID: ORCID
Rencai Jin
3
ORCID: ORCID
Laiwang Jing
1
ORCID: ORCID

  1. Anhui University of Science and Technology, State key Laboratory of Mining response and disaster Prevention and Control in Deep Coal Mines, 168 Taifeng Street, Huainan City, Anhui Province, China
  2. Anhui University of Science and Technology, School of Civil Engineering and Architecture, 168 Taifeng Street, Huainan City, Anhui Province, China
  3. China MCC17 Group Co., LTD., Civil Engineering Post-doctoral Research Worktation, No. 88 Yushan East Road, Huashan District, Ma’anshan City, Anhui Province, China
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Abstract

The efficient protection (support reinforcement) of a wall and heading crossing ensures continuity of the production cycle, and that is a quick moving of the scraper conveyor to the wall. Using low or high bolting as a support reinforcement element in wall and heading crossings allows for the elimination of traditional methods of maintaining longwall-gate crossings, and therefore allows for the efficient use high performance modern wall complexes. The paper presents the long underground experience, of the Knurów–Szczygłowice mine of efficient support wall and heading crossing maintenance, which was bolted to the rock mass with the usage of two pairs of bolts, showing full technical and economical usefulness of this support reinforcement method. The article also highlights work safety and the increasingly common usage of endoscopies when specifying the range of crack areas which directly effects the proper choice in number, load-capacity and length of the used bolts. The underground studies the measurements of the reach of the zones of fracturing and roof stratification (using endoscopes and wire type stratification meters) and the laboratory tests (using the test stand) have allowed to determine the safety factor for maintenance of the longwall gangway crossing, directly resulting in the necessity to install additional reinforcement. The value of the safety factor Sbsc-ch greater than 1 is advantageous and safe, and the value less than or equal to 1 can lead to a significant deterioration of the conditions of maintenance of a wall and heading crossing which was bolted.

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Authors and Affiliations

Stanisław Duży
Piotr Głuch
Grzegorz Michalik
Adam Ratajczak
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Abstract

The study area of the Nida valley was examined to investigate variations in groundwater and surface water levels, as well as the interaction between them. In the valley, there were three branches. The two actives were the Nida River itself and the Smuga Umianowicka branch while the Stara Nida branch was dry during the measurement session. Over a 12-month period from June 2021 to June 2022, 7 monitoring points were equipped with piezometers, comprising 5 groundwater points and 2 surface water points. The monitoring frequency was set to 30 minutes. The results of this research indicate that there are significant differences in the water level at the same observed point at different times. This study demonstrates seasonal changes in both surface water and groundwater levels with higher levels in autumn and winter and lower levels in spring and summer, which are closely tied to the changes in meteorological conditions during the research period, such as precipitation and air temperature. The study results also indicate that during summer and winter at the Nida River and its riparian area, losing stream is the primary process occurring in the studied reach. Conversely, during autumn and spring, the main process is gaining stream. At the human-maintained Smuga Umianowicka branch and in its riparian area, losing stream is the main process during summer and autumn, and gaining stream is the main process during spring. During winter, losing stream and gaining stream processes can occur simultaneously, and neither process takes place mainly.
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Authors and Affiliations

Cong Ngoc Phan
1 2
ORCID: ORCID
Andrzej Strużyński
1
ORCID: ORCID
Tomasz Kowalik
1
ORCID: ORCID

  1. University of Agriculture in Krakow, Faculty of Environmental Engineering and Land Surveying, al. Mickiewicza 24/28, 30-059 Kraków, Poland
  2. Vinh University, Institute of Chemistry, Biology and Environment, 182 Le Duan St, Vinh City, Nghe An Province, Vietnam
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Abstract

In the mining galleries of the abandoned Au-As mine in Radzimowice, diverse groups of secondary arsenates crystallized recently. They form several characteristic assemblages. In the first of them the typical minerals are bukovskýite and melanterite. The second group of secondary arsenates includes scorodite, kaňkite, zýkaite, and pitticite. The third assemblage includes Co-Ni-Mg arsenates of the erythrite-annabergite-hörnesite series. The first assemblage crystallized in a zone with a very high activity of sulphate and arsenate ions and where the pH varies within a narrow range of 2.0–3.5. The second group of secondary arsenates formed in the acidic zone. The minerals identified here suggest pH variation within fairly wide ranges, from about 2.0 to 5.5. Contrary to the first and second mineral assemblage, the Co-Ni-Mg arsenates formed under different geochemical conditions. Their crystallization took place under weak acidic to neutral conditions.
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Authors and Affiliations

Rafał Siuda
1
Anna Januszewska
1

  1. University of Warsaw, Faculty of Geology, Żwirki i Wigury 93, 02-098 Warszawa, Poland
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Abstract

The structural pattern developed within metre to microscopic scale thrust and strike-slip fault zones exposed in the Palaeogene flysch rocks of the Fore-Dukla Thrust Sheet in the south-eastern part of the Silesian Nappe, Outer Carpathians, Poland, reveals evidence for upper crustal deformation and fluid flow. Syntectonic dawsonite [NaAlCO3(OH)2] indicates the following series of deformational events within the fault zones: i) detachment and buckle folding resulting from movement along thrust faults; ii) faulting as a compensation of the shortening, resulting in the fault propagation folding, breakthrough thrust faulting and imbrications; and iii) strike-slip faulting. The microstructural pattern coupled with the growth of a related sequence of carbonate minerals within the fault zones, followed by present-day dawsonite precipitation and tufa formation, indicate a continuing influence of fluids within the Silesian Nappe up to and including modern time. Structural observations at metre to microscopic scales coupled with EDS mapping of rocks indicate that dawsonite is a unique tool for the reconstruction of subsequent deformation in the Fore-Dukla Thrust Sheet.

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Authors and Affiliations

Barbara Rybak-Ostrowska
Arkadiusz Gąsiński
Grzegorz Kaproń
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Abstract

The article presents the use of computer graphics methods and computational geometry for the analysis on changes of geometrical parameters for a mixed zone in resistance-heated samples. To perform the physical simulation series of resistance heating process, the Gleeble 3800 physical simulator, located in the Institute for Ferrous Metallurgy in Gliwice, was used. The paper presents a description of the test stand and the method for performing the experiment. The numerical model is based on the Fourier-Kirchoff differential equation for unsteady heat flow with an internal volumetric heat source. In the case of direct heating of the sample, geometrical parameters of the remelting zone change rapidly. The described methodology of using shape descriptors to characterise the studied zone during the process allows to parametrise the heat influence zones. The shape descriptors were used for the chosen for characteristic timing steps of the simulation, which allowed the authors to describe the changes of the studied parameters as a function of temperature. Additionally, to determine the impact of external factors, the remelting zone parameters were estimated for two types of grips holding the sample, so-called hot grips of a shorter contact area with the sample, and so-called cold grips. Based on the collected data, conclusions were drawn on the impact of the process parameters on the localisation and shape of the mushy zone.

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Authors and Affiliations

Tomasz Dębiński
ORCID: ORCID
Marcin Hojny
M. Głowacki
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Abstract

This paper presents an experimental investigation on the mechanical properties and microstructure of geopolymer repair materials mixed using fly ash (FA) and concrete substrates. An optimal combination of FA and concrete substrate was determined using the compressive test of geopolymer mortar mixed with various concrete substrate classes. It was found that the contribution of (C35/45) concrete substrates with the FA geopolymer mortar increases the 28-day bonding strength by 25.74 MPa. The microstructure analysis of the samples using scanning electron microscopy showed the denser structure owing to the availability of high calcium and iron elements distribution. These metal cations (Ca2+ and Fe3+) are available at OPC concrete substrate as a result from the hydration process reacted with alumina-silica sources of FA and formed calcium aluminate silicate hydrate (C-A-S-H) gels and Fe-bonding linkages.
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Authors and Affiliations

Mohd Mustafa Al Bakri Abdullah
1 2
ORCID: ORCID
Ikmal Hakem A. Aziz
1
ORCID: ORCID
Warid Wazien Ahmad Zailani
3
ORCID: ORCID
Shayfull Zamree Abd Rahim
1
ORCID: ORCID
Heah Cheng Yong
1 2
ORCID: ORCID
Andrei Victor Sandu
4
ORCID: ORCID
Loke Siu Peng
1

  1. Universiti Malaysia Perlis (UniMAP), Centre of Excellence Geopolymer and Green Technology (CEGeoGTech), Perlis, Malaysia
  2. Universiti Malaysia Perlis (UniMAP), Faculty of Chemical Engineering Technology, Perlis, Malaysia
  3. Universiti Teknologi Mara (UiTM), Faculty of Civil Engineering, Shah Alam, Selangor, Malaysia
  4. “Gheorghe Asachi” Technical University of Iasi, Faculty of Materials Science and Engineering, Romania

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