Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 11
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

Waters with mineralization above 1000 mg/dm3, classified as mineral waters, are exploited in many regions of Poland. Their resources are usually not renewable and their excessive exploitation can lead to the deterioration of their physical and chemical properties and negatively affect their quantitative status.

The stages in the life of a groundwater deposit involve prospecting, exploration, development, and exploitation. Deposit management is the basis for a sustainable and economically successful process of using water resources.

The problem of effective management of mineral water deposit management has not been raised so far, which is why the authors decided to address issues that should be taken into account in the abovementioned process. An integrated approach to the prospecting, exploration, opening, and exploitation of mineral waters combining the knowledge of specialists from various disciplines (hydrogeologists, geologists, drillers and producers) will enable the appropriate management of these resources.

The article describes the basic elements of the process, special attention has been paid to the mineral water deposit development plan conditioning the correct and economically justified exploitation of these waters. This plan should take the development strategy and legal and environmental conditions into account. Hydrogeological and mathematical models of mineral water deposits developed as part of the plan provide the basis for determining the extent of the mining area and estimating water resources. The deposit opening, exploitation, and monitoring methods are important elements of the deposit development plan.

Go to article

Authors and Affiliations

Barbara Uliasz-Misiak
ORCID: ORCID
Elżbieta Wojna-Dyląg
Download PDF Download RIS Download Bibtex

Abstract

Shear connectors are designed in steel-concrete composite construction to transmit the longitudinal shear, to prevent separation of steel and concrete slabs, and also to increase the structural efficiency of the whole system. In this study, the performances of different types of shear connectors in steel-concrete composite specimens are evaluated by conducting push-out tests under monotonic loading conditions. An ISMB 200 @ 25.4 kg/m universal steel beam measuring 400 mm and a reinforced cement concrete slab measuring 300 mm with a breadth of 200 mm and a thickness of 200 mm reinforced with 8 mm diameter steel rods are used for the experimental study. The results reveal that the load-slip relationships for various types of shear connectors and failure mechanisms are obtained to identify those shear connectors which are more relevant to the steel – concrete composite members.

Go to article

Authors and Affiliations

V. Jayanthi
C. Umarani
Download PDF Download RIS Download Bibtex

Abstract

The use of FRP materials as external reinforcement of masonry structures has been recognized as an effective and minimally invasive method ofwall strengthening. The available literature and research reports confirmthe positive effect of the strip-like arrangement of composites with a horizontal, diagonal and – as shown in the paper – vertical configuration. The problem here is the proper estimation of the benefits of such FRP reinforcement, namely determining the real increase in shear strength. The paper described selected calculation procedures that can be found in the available literature (proprietary solutions), as well as in the published guidelines for the design of masonry walls strengthening using FRP materials. The results of experimental tests of sheared masonry walls made of AAC blocks and strengthened using vertical strips of carbon and glass fibres are briefly presented. Finally, based on the presented formulae, the values of the theoretical shear force resulted from the FRP contribution were calculated and detailed discussed.
The comparison of the experimental and theoretical shear forces showed that only one of the presented calculation methods gave a high agreement of the results for both carbon and glass sheets. In addition, it was noticed that in two cases the effects of strengthening – depending on the material used – drastically differed, which was not observed in the research.
Go to article

Authors and Affiliations

Marta Kałuża
1
ORCID: ORCID

  1. Silesian University of Technology, Faculty of Civil Engineering, Akademicka 5, 44-100 Gliwice, Poland
Download PDF Download RIS Download Bibtex

Abstract

The paper describes the recent developments of Hybrid Fibre-Reinforced Polymer (HFRP) and nano-Hybrid Fibre-Reinforced Polymer (nHFRP) bars. Hybridization of less expensive basalt fibres with carbon fibres leads to more sustainable alternative to Basalt-FRP (BFRP) bars and more economically-efficient alternative to Carbon-FRP (CFRP) bars. The New-Developed HFRP bars were subjected to tensile axial loading to investigate its structural behaviour. The effect of hybridization on tensile properties of HFRP bars was verified experimentally by comparing the results of tensile test of HFRP bars with non-hybrid BFRP bars. It is worth to mention that the difference in obtained strength characteristics between analytical and numerical considerations was very small, however the obtained results were much higher than results obtained experimentally. Authors suggested that lower results obtained experimentally can be explained by imperfect interphase development and therefore attempted to improve the chemical cohesion between constituents by adding nanosilica particles to matrix consistency.

Go to article

Authors and Affiliations

E.D. Szmigiera
K. Protchenko
M. Urbański
A. Garbacz
Download PDF Download RIS Download Bibtex

Abstract

Information and decision projects in the area of civil engineering are usually complex and heterogeneous. This, in turn, requires the use of IT solutions to support them. The selection of the appropriate models for data or knowledge representation, which are the information resources of such systems in connection with the selection of analytical and decision models, can be considered as one of the elements of the rationalization of engineering projects. The approach that takes account of the significant complexity and heterogeneity of problems is a system approach with the use of an objectoriented way of organizing data or knowledge. Not only does it ensure efficient modelling of information and decision processes in the field of engineering projects (also in crisis situations), due to the uniformity of the model approach, it also allows for maintaining the continuity of the implementation of complex processes of various specificity, e.g. the different levels of structuring or the randomness of partial problems.
Go to article

Authors and Affiliations

Janusz Szelka
1

  1. University of Zielona Góra, Institute of Civil Engineering, St. Prof. Z. Szafrana 1, 65-516 Zielona Góra, Poland
Download PDF Download RIS Download Bibtex

Abstract

The paper describes factors influencing the development of electricity storage technologies.

The results of the energy analysis of the electric energy storage system in the form of hydrogen are

presented. The analyzed system consists of an electrolyzer, a hydrogen container, a compressor, and

a PEMFC fuel cell with an ion-exchange polymer membrane. The power curves of an electrolyzer

and a fuel cell were determined. The analysis took the own needs of the system into account, i.e. the

power needed to compress the produced hydrogen and the power of the air compressor supplying

air to the cathode channels of the fuel cell stack. The characteristics describing the dependence

of the efficiency of the energy storage system in the form of hydrogen as a function of load were

determined. The costs of electricity storage as a function of storage capacity were determined. The

energy aspects of energy accumulation in lithium-ion cells were briefly characterized and described.

The efficiency of the charge/discharge cycle of lithium-ion batteries has been determined. The

graph of discharge of the lithium-ion battery depending on the current value was presented. The key

parameters of battery operation, i.e. the Depth of Discharge (DoD) and the State of Charge (SoC),

were determined. Based on the average market prices of the available lithium-ion batteries for the

storage of energy from photovoltaic cells, unit costs of electrochemical energy storage as a function

of the DoD parameter were determined.

Go to article

Authors and Affiliations

Bartosz Ceran
Download PDF Download RIS Download Bibtex

Abstract

Matched sampling is a methodology used to estimate treatment effects. A caliper mechanism is used to achieve better similarity among matched pairs. We investigate finite sample properties of matching with caliper and propose a slight modification to the existing mechanism. The simulation study compare performance of both methods and show that standard caliper perform well only in case of constant treatment or uniform propensity score distribution. Secondly, in a case of non-uniform distribution and non-uniform treatment the dynamic caliper method outperform standard caliper matching.

Go to article

Authors and Affiliations

Paweł Strawiński
Download PDF Download RIS Download Bibtex

Abstract

This paper reports the results of research involving observations of flow patterns during air-oil-water three-phase flow through a vertical pipe with an internal diameter of 0.03 m and a length of 3 m. The conductometric method based on the measurement of electrical conductivity of the gas-liquid-liquid system was used to evaluate the flow patterns. In the studies, a set of eight probes spaced concentrically in two tube sections (four probes per each) with a spacing of 0.015 m were used. The paper presents a theoretical description of the test method and the analysis of the measurement results for air-oil-water multiphase flow system. Results of this study indicate that the developed method of characterizing the voltage of the gas-liquid-liquid system can be an important tool supporting other methods to identify flow patterns, including visual observation.

Go to article

Authors and Affiliations

Małgorzata Płaczek
Marcin Pietrzak
Stanisław Witczak
Download PDF Download RIS Download Bibtex

Abstract

Room-temperature ionic liquids (RTILs) are a moderately new class of liquid substances that are characterized by a great variety of possible anion-cation combinations giving each of them different properties. For this reason, they have been termed as designer solvents and, as such, they are particularly promising for liquid-liquid extraction, which has been quite intensely studied over the last decade. This paper concentrates on the recent liquid-liquid extraction studies involving ionic liquids, yet focusing strictly on the separation of n-butanol from model aqueous solutions. Such research is undertaken mainly with the intention of facilitating biological butanol production, which is usually carried out through the ABE fermentation process. So far, various sorts of RTILs have been tested for this purpose while mostly ternary liquid-liquid systems have been investigated. The industrial design of liquid-liquid extraction requires prior knowledge of the state of thermodynamic equilibrium and its relation to the process parameters. Such knowledge can be obtained by performing a series of extraction experiments and employing a certain mathematical model to approximate the equilibrium. There are at least a few models available but this paper concentrates primarily on the NRTL equation, which has proven to be one of the most accurate tools for correlating experimental equilibrium data. Thus, all the presented studies have been selected based on the accepted modeling method. The reader is also shown how the NRTL equation can be used to model liquid-liquid systems containing more than three components as it has been the authors’ recent area of expertise.

Go to article

Authors and Affiliations

Artur Kubiczek
Władysław Kamiński
Download PDF Download RIS Download Bibtex

Abstract

Referring to a book by A. Eriksen (Oslo 2007) the author discusses the development of the Norwegian historiography of the 17th–18th centuries and attempts to determine the role played by the so called “topographers”, who represented the antiquarian and/or erudite approach to historical writing.
Go to article

Authors and Affiliations

Krystyna Szelągowska
ORCID: ORCID
Download PDF Download RIS Download Bibtex

Abstract

This article concerns fully developed laminar flow of a viscous incompressible fluid in a long composite cylindrical channel. Channel consist of three regions. Outer and inner regions are of uniform permeability and mid region is a clear region. Brinkman equation is used as a governing equation of motion in the porous region and Stokes equation is used for the clear fluid region. Analytical expressions for velocity profiles, rate of volume flow and shear stress on the boundaries surface are obtained and exhibited graphically. Effect of permeability variation parameter on the flow characteristics has been discussed.

Go to article

Bibliography

[1] A.K. Al-Hadhrami, L. Elliot, D.B. Ingham, and X. Wen. Analytical solutions of fluid flows through composite channels. Journal of Porous Media, 4(2), 2001. doi: 10.1615/JPorMedia.v4.i2.50.
[2] A.K. Al-Hadhrami, L. Elliot, D.B. Ingham, and X. Wen. Fluid flows through two-dimensional channel of composite materials. Transport in Porous Media, 45(2):281–300, 2001. doi: 10.1023/A:1012084706715.
[3] A. Haji-Sheikh and K. Vafai. Analysis of flow and heat transfer in porous media imbedded inside various-shaped ducts. International Journal of Heat and Mass Transfer, 47(8-9):1889–1905, 2004. doi: 10.1016/j.ijheatmasstransfer.2003.09.030.
[4] A.V. Kuznetsov. Analytical investigation of Couette flow in a composite channel partially filled with a porous medium and partially with a clear fluid. International Journal of Heat and Mass Transfer, 41(16):2556–2560, 1998. doi: 10.1016/S0017-9310(97)00296-2.
[5] C.Y. Wang. Analytical solution for forced convection in a semi-circular channel filled with a porous medium. Transport in Porous Media, 73(3):369–378, 2008. doi: 10.1007/s11242-007-9177-5.
[6] D.A. Nield, S.L.M. Junqueira, and J.L. Lage. Forced convection in a fluid-saturated porous medium channel with isothermal or isoflux boundaries. Journal of Fluid Mechanics, 322:201–214, 1996. doi: 10.1017/S0022112096002765.
[7] H.C. Brinkman. On the permeability of media consisting of closely packed porous particles. Applied Scientific Research, 1:81–86, 1949. doi: 10.1007/BF02120318.
[8] I. Pop and P. Cheng. Flow past a circular cylinder embedded in a porous medium based on the Brinkman model. International Journal of Engineering Science, 30(2):257–262, 1992. doi: 10.1016/0020-7225(92)90058-O.
[9] K. Hooman and H. Gurgenci. A theoretical analysis of forced convection in a porous saturated circular tube: Brinkman-Forchheimer model. Transport in Porous Media, 69:289–300, 2007. doi: 10.1007/s11242-006-9074-3.
[10] K. Vafai and S.J. Kim. Forced convection in a channel filled with a porous medium: An exact solution. Journal of Heat Transfer, 111(4):1103–1106, 1989. doi: 10.1115/1.3250779.
[11] M. Kaviany. Laminar flow through a porous channel bounded by isothermal parallel plates. International Journal of Heat and Mass Transfer, 28(4):851–858, 1985. doi: 10.1016/0017-9310(85)90234-0.
[12] M. Parang and M. Keyhani. Boundary effects in laminar mixed convection flow through an annular porous medium. Journal of Heat Transfer, 109(4):1039–1041, 1987. doi: 10.1115/1.3248179.
[13] P. Vadasz. Fluid flow through heterogenous porous media in a rotating square channel. Transport in Porous Media, 12(1):43–54, 1993. doi: 10.1007/BF00616361.
[14] S. Chikh, A. Boumedien, K. Bouhadef, and G. Lauriat. Analytical solution of non-Darcian forced convection in an annular duct partially filled with a porous medium. International Journal of Heat and Mass Transfer, 38(9):1543–1551, 1995. doi: 10.1016/0017-9310(94)00295-7.
[15] S. Govender. An analytical solution for fully developed flow in a curved porous channel for the particular case of monotonic permeability variation. Transport in Porous Media, 64:189–198, 2006. doi: 10.1007/s11242-005-2811-1.
[16] S.K. Singh and V.K. Verma. Flow in a composite porous cylindrical channel covered with a porous layer of varaible permeability. Special Topics & Reviews in Porous Media – An International Journal, 10(3):291–303, 2019.
[17] V.K. Verma and S. Datta. Flow in a channel filled by heterogeneous porous mediuum with a linear permeability variation. Special Topics & Reviews in Porous Media – An International Journal, 3(3):201–208, 2012. doi: 10.1615/SpecialTopicsRevPorousMedia.v3.i3.10.
[18] V.K. Verma and S.K. Singh. Flow in a composite porous cylindrical channel of variable permeability covered with porous layer of uniform permeability. International Journal of Pure and Applied Mathematics, 118(2):321–334, 2018.
[19] V.K. Verma and H. Verma. Exact solutions of flow past a porous cylindrical shell. Special Topics & Reviews in Porous Media – An International Journal, 9(1):91–99, 2018. doi: 10.1615/SpecialTopicsRevPorousMedia.v9.i1.110.
[20] M. Abramowitz and I.A. Stegun. A Handbook of Mathematical Functions with Formulas, Graphs and Mathematical Tables. Dover Publications, New York, 1972.
Go to article

Authors and Affiliations

Sanjeeva Kumar Singh
1
Vineet Kumar Verma
1

  1. Department of Mathematics and Astronomy, University of Lucknow, India.

This page uses 'cookies'. Learn more