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Tytuł:
Importance of cut - off line in automotive headlamps aiming
Autorzy:
Targosiński, T.
Powiązania:
https://bibliotekanauki.pl/articles/246827.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
headlights aiming
cut-off line
road illumination
glare protection
Opis:
The basic element of passing beam headlights is the "cut-off line". It was intended in European beam pattern as tool for correct adjustment of passing beam according good road illumination distance and oncoming drive eyes protection of excessive glare. Cut-off line was established on the one hand as a natural part separating bright and dark area in the conventional passing beam, on the other assigned its essential function of the visual aiming of headlights. It is used in laboratory practices as well as in vehicles factories and in services and technical periodical inspection. The most important is that cut-off line was defined visually and subjectively over 50 years ago. But needed aiming precision according guaranteed road visibility and glare protection is much higher than historically moulded practical cut-off performance. In paper is analysed definition of cut-off line, their performance and meaning, historical evolution and influence for technical development of headlamps design. Also, mathematical approximation and modelling of cut-off line visual perception is described. The important is analysis of practical examples of real cut-off lines, their connections with significant beam pattern characteristics and possible ambiguous aiming during type approval and during vehicle exploitation. Also, analyzed are perspectives of future cut-off line use, development or - may be replacement by other means better serving this very important task to guarantee correct adjustment beam pattern according good road illumination and protection against excessive glare.
Źródło:
Journal of KONES; 2012, 19, 3; 469-476
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fluidised fly-ash cement-bentonite cut-off walls in flood protection
Autorzy:
Falaciński, P.
Garbulewski, K.
Kledyński, Z.
Skutnik, Z.
Ziarkowska, K.
Powiązania:
https://bibliotekanauki.pl/articles/241281.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
cut-off walls
slurry properties
fluidised fly-ash
flood protection
Opis:
Vertical barrier walls are widely used in environmental control systems to restrict the lateral spreading of liquid or gaseous contaminants and for seepage control through and beneath levees. The barrier walls are constructed in single or two phases using slurry composed mainly of bentonite, cementitious materials and water to maintain the trench stability and finally low hydraulic conductivity of barrier. A turning point in the development of slurry technology arose from research demonstrating the positive effects of blast furnace slag or fly-ashes on slurry properties in terms of reduced hydraulic conductivity. This paper presents the implementation of an experimental section of cut-off wall in the subsoil of a modernised flood embankment along the Vistula River and the results of controlling analyses of applied hardening slurry with an admixture of activated fluidal ashes from hard coal. The results of tests confirm the possibility of practical application of fluidal ashes as active components to hardening slurry and obtaining - depending on the suspension composition - of favourable technological and exploitation properties of this material.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2005, 52, 1; 7-20
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetorheological self-powered vibration reduction system with current cut-off: experimental investigation
Autorzy:
Jastrzębski, Ł.
Sapiński, B.
Powiązania:
https://bibliotekanauki.pl/articles/386843.pdf
Data publikacji:
2018
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
MR damper
vibration
energy harvesting
current cut-off circuit
Opis:
The paper summarises the results of laboratory testing of an energy harvesting vibration reduction system based on a magnetorheological (MR) damper whose control circuit incorporates a battery of bipolar electrolytic capacitors (current cut-off circuit). It is designed to reduce the undesired effects in vibration reduction systems of this type, associated with the increasing amplitude of the sprung mass vibration under the excitation inputs whose frequency should exceed the resonance frequency of the entire system. Results have demonstrated that incorporating a current cut-off circuit results in a significant decrease of sprung mass vibration amplitudes when the frequency of acting excitation inputs is higher than the resonance frequency.
Źródło:
Acta Mechanica et Automatica; 2018, 12, 2; 96-100
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensor performance and cut-off wavelength tradeoffs of III-V focal plane arrays
Autorzy:
James, Jonathan Ch.
Haran, Terence L.
Lane, Sarah E.
Powiązania:
https://bibliotekanauki.pl/articles/2204205.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
infrared focal plane arrays
III-V semiconductor infrared detector technologies
infrared sensor performance modelling
infrared sensor design
mid-wave and longwave infrared sensors
Opis:
Infrared detector technologies engineered from III-V semiconductors such as strained-layer superlattice, quantum well infrared photodetectors, and quantum dot infrared photodetectors provide additional flexibility to engineer bandgap or spectral response cut-offs compared to the historical high-performance detector technology of mercury/cadmium/telluride. The choice of detector cut-off depends upon the sensing application for which the system engineer is attempting to maximize performance within an expected ensemble of operational scenarios that define objects or targets to be detected against specific environmental backgrounds and atmospheric conditions. Sensor performance is typically characterised via one or more metrics that can be modelled or measured experimentally. In this paper, the authors will explore the impact of detector cut-off wavelength with respect to different performance metrics such as noise equivalent temperature difference and expected target detection or identification ranges using analytical models developed for several representative sensing applications encompassing a variety of terrestrial atmospheric conditions in the mid-wave and long-wave infrared wavelength bands. The authors will also report on their review of recently published literature concerning the relationships between cut-off wavelength and the other detector performance characteristics such as quantum efficiency or dark current for a variety of detector technologies.
Źródło:
Opto-Electronics Review; 2023, 31, Special Issue; art. no. e144570
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High performance type-II InAs/GaSb superlattice infrared photodetectors with a short cut-off wavelength
Autorzy:
Delmas, Marie
Ramos, David
Ivanov, Ruslan
Žurauskaitė, Laura
Evans, Dean
Rihtnesberg, David
Almqvist, Susanne
Becanovic, Smilja
Costard, Eric
Höglund, Linda
Powiązania:
https://bibliotekanauki.pl/articles/2204225.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
infrared detectors
short-wavelength infrared
InAs/GaSb superlattice
type-II superlattice
Opis:
This work investigates the potential of InAs/GaSb superlattice detectors for the shortwavelength infrared spectral band. A barrier detector structure was grown by molecular beam epitaxy and devices were fabricated using standard photolithography techniques. Optical and electrical characterisations were carried out and the current limitations were identified. The authors found that the short diffusion length of ~1.8 µm is currently limiting the quantum efficiency (double-pass, no anti-reflection coating) to 43% at 2.8 µm and 200 K. The dark current density is limited by the surface leakage current which shows generation-recombination and diffusion characters below and above 195 K, respectively. By fitting the size dependence of the dark current, the bulk values have been estimated to be 6.57·10ˉ⁶ A/cm² at 200 K and 2.31·10ˉ⁶ A/cm² at 250 K, which is only a factor of 4 and 2, respectively, above the Rule07.
Źródło:
Opto-Electronics Review; 2023, 31, Special Issue; art. no. e144555
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Static anti-windup compensator based on BMI optimisation for discrete-time systems with cut-off constraints
Autorzy:
Horla, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/2090701.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
anti-windup compensation
bilinear matrix inequalities
cut-off constraint
kompensacja zjawiska windup
dwuliniowe nierówności macierzy
ograniczenie odcięcia
Opis:
In the paper, a design method of a static anti-windup compensator for systems with input saturations is proposed. First, an anti-windup controller is presented for system with cut-off saturations, and, secondly, the design problem of the compensator is presented to be a non-convex optimization problem easily solved using bilinear matrix inequalities formulation. This approach guarantees stability of the closed-loop system against saturation nonlinearities and optimizes the robust control performance while the saturation is active.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 1; e135837, 1--8
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Static anti-windup compensator based on BMI optimisation for discrete-time systems with cut-off constraints
Autorzy:
Horla, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/2173541.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
anti-windup compensation
bilinear matrix inequalities
cut-off constraint
kompensacja zjawiska windup
dwuliniowe nierówności macierzy
ograniczenie odcięcia
Opis:
In the paper, a design method of a static anti-windup compensator for systems with input saturations is proposed. First, an anti-windup controller is presented for system with cut-off saturations, and, secondly, the design problem of the compensator is presented to be a non-convex optimization problem easily solved using bilinear matrix inequalities formulation. This approach guarantees stability of the closed-loop system against saturation nonlinearities and optimizes the robust control performance while the saturation is active.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 1; art. no. e135837
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance Analysis of a Dual Cycle Engine with Considerations of Pressure Ratio and Cut-Off Ratio
Autorzy:
Ebrahimi, R.
Powiązania:
https://bibliotekanauki.pl/articles/1535596.pdf
Data publikacji:
2010-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Ln
82.60.Fa
88.05.-b
Opis:
The dual cycle is a better approximation to the modern high speed compression ignition engine than either the Diesel cycle or the Otto cycle. Therefore, this study is aimed at investigating the effects of pressure and cut-off ratios on the dual cycle performance with considerations of heat transfer loss, variable specific heat ratio and friction irreversible losses. By using finite-time thermodynamics theory, the relations between the power output and the compression ratio, between the thermal efficiency and the compression ratio, as well as the optimal relation between power output and the efficiency of the cycle are obtained. The results show that if compression ratio is smaller than certain value, the increase of pressure ratio and the decrease of cut-off ratio make the power output bigger. While if compression ratio exceeds certain value, the power output first increases and then starts to decline as pressure ratio and cut-off ratio are increased. With further increase in compression ratio, the power output decreases with increasing pressure ratio and decreasing cut-off ratio. The effects of pressure and cut-off ratios on the variation of the thermal efficiency with compression ratio are similar to those for the power output. The results obtained in this work can provide significant guidance for the performance evaluation and improvement of modern high speed compression ignition engines.
Źródło:
Acta Physica Polonica A; 2010, 118, 4; 534-539
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Peritraumatic distress among emergency medical system employees: a proposed cut-off for the Peritraumatic Distress Inventory
Autorzy:
Rybojad, B.
Aftyka, A.
Milanowska, J.
Powiązania:
https://bibliotekanauki.pl/articles/2085172.pdf
Data publikacji:
2019
Wydawca:
Instytut Medycyny Wsi
Tematy:
paramedics
Peritraumatic Distress Inventory
peritraumatic distress
post-traumatic stress disorder
Opis:
Introduction. Emergency medical system (EMS) workers are exposed to traumatic events that may lead to posttraumatic stress disorder (PTSD). Objectives. The purpose of this study was to explore and discuss the relationship between peritraumatic distress (PD) and elevated posttraumatic stress symptoms (PTSS) in EMS employees. Material and methods. A cross-sectional study including 100 EMS employees was conducted. Demographic and occupational data were collected for each subject. The Polish version of the Impact of Event Scale-Revised (IES-R) was used to evaluate PTSS and the Polish version of the Peritraumatic Distress Inventory (PDI) was used to determine the level of PD experienced during and immediately after a traumatic event. Results. The highest scores indicative of distress were obtained on the negative emotions subscale, and the lowest on the loss of control and arousal (LCA) subscales. A strong positive correlation was found between the severity of PD and PTSS. Among the PDI subscales, the severity of PTSS was most strongly correlated with LCA, and had the weakest correlation with sense of threat. The optimal PDI cut-off score for predicting elevated PTSS was 19. Conclusions. PD is strongly related to elevated PTSS and serves as a useful tool for screening EMS workers at risk of developing PTSD. Individuals with PDI scores of 19 or higher are good candidates for specialist consultations aimed at detecting and treating elevated PTSS.
Źródło:
Annals of Agricultural and Environmental Medicine; 2019, 26, 4; 579-584
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SPH - a comparison of neighbor search methods based on constant number of neighbors and constant cut-off radius
Autorzy:
Wróblewski, P.
Kopeć, M.
Boryczko, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/1933174.pdf
Data publikacji:
2007
Wydawca:
Politechnika Gdańska
Tematy:
SPH
simulations
incompressible fluids
constant cut-off radius method
constant number of neighbors method
breaking dam
side gap
time effectiveness
Opis:
Two methods of neighbor search for the SPH algorithm are presented, based on a constant number of neighbors and a constant cut-off radius. First, feasible methods of comparison were analyzed. Then, the two selected methods were compared visually and computationally. Considering the use of the SPH algorithm for simulating incompressible fluids, the obtained results suggest that the method with a constant cut-off radius is better than that with a constant number of neighbors. The simulation results of both methods are practically indistinguishable, while the computational costs favor one of them.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2007, 11, 3; 273-283
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydraulic Conductivity and Porosity of Hardening Slurries with Fluidal Fly Ashes in Chemically Aggressive Environments
Autorzy:
Falaciński, P.
Kledyński, Z.
Powiązania:
https://bibliotekanauki.pl/articles/241022.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
hardening slurry
fluidal ashes
cut-off walls
hydraulic conductivity
Opis:
The article presents the results of hydraulic conductivity and porosity tests of hardening slurries prepared from Portland cement, betonite, water and fluidal fly ashes from combustion of hard and brown coal. In addition, the ashes were in two states of activation: non-activated and mechanically activated. The slurries were exposed to persistent, 160-day filtration of chemically aggressive liquids: distilled water, 0.5% solution of nitric acid and 1% solution of sodium sulphate. A comparative base was composed of samples exposed to filtration of tap water. The research was into relations between hydraulic conductivity and parameters characterizing the porosity structures in slurries, as well as into the influence of sample maturation periods, the state of activation and type of ashes, and the type of aggressive medium on porosity and conductivity of the material. The observed phenomena were typical of materials based on cement binders, and exposed to chemical aggression, e.g. sealing-up of porosity structures in response to sulphate corrosion and de-sealing in response to leaching corrosion, along with effects specific for slurries, such as a decrease of hydraulic conductivity in response to nitric acid solution. A favourable effect of fluidal fly ashes from brown coal was also noted.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2008, 55, 3-4; 65-81
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling SiGe-base HBT using APSYS 2000 - a 2D simulator
Autorzy:
Linkowski, A.
Łukasiak, L.
Jakubowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/308023.pdf
Data publikacji:
2004
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
base transit time
cut-off frequency
HBT
SiGe-base
Opis:
The paper is devoted to optimization of SiGe-base HBT with respect to operation speed by means of numerical simulation. The influence of design parameters on f(T) is studied.
Źródło:
Journal of Telecommunications and Information Technology; 2004, 1; 36-38
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of the cut-off grade for underground polymetallic mines
Optymalizacja wartości granicznej surowca dla podziemnych kopalń rud polimetalicznych
Autorzy:
Liu, Di
Li, Guoqing
Hu, Nailian
Xiu, Guolin
Ma, Zhaoyang
Powiązania:
https://bibliotekanauki.pl/articles/216136.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
cut-off grade
marginal economics
underground polymetallic mine
ocena graniczna
ekonomia krańcowa
podziemna kopalnia polimetaliczna
Opis:
One of the most critical aspects of mine design is to determine the optimum cut-off grade. Despite Lane’s theory, which aims to optimize the cut-off grade by maximizing the net present value (NPV), which is now an accepted principle used in open pit planning studies, it is less developed and applied in optimizing the cut-off grade for underground polymetallic mines than open pit mines, as optimization in underground polymetallic mines is more difficult. Since there is a similar potential for optimization between open pit mines and underground mines, this paper extends the utilization of Lane’s theory and proposes an optimization model of the cut-off grade applied to combined mining-mineral processing in underground mines with multi-metals. With the help of 3D visualization model of deposits and using the equivalent factors, the objective function is expressed as one variable function of the cut-off grade. Then, the curves of increment in present value versus the cut-off grade concerning different constraints of production capacities are constructed respectively, and the reasonable cut-off grade corresponding to each constraint is calculated by using the golden section search method. The defined criterion for the global optimization of the cut-off grade is determined by maximizing the overall marginal economics. An underground polymetallic copper deposit in Tibet is taken as an example to validate the proposed model in the case study. The results show that the overall optimum equivalent cut-off grade, 0.28%, improves NPV by RMB 170.2 million in comparison with the cut-off grade policy currently used. Thus, the application of the optimization model is conducive to achieving more satisfactory economic benefits under the premise of the rational utilization of mineral resources.
Jednym z najbardziej istotnych aspektów projektowania kopalni jest określenie optymalnej wartości granicznej surowca. Pomimo teorii Lane’a, mającej na celu optymalizację wartości granicznej surowca poprzez maksymalizację wartości bieżącej netto (NPV), obecnie stosowanej w studiach planowania górnictwa odkrywkowego, natomiast jest ona mniej rozwinięta i stosowana w optymalizowaniu wartości granicznej surowca dla podziemnych kopalń rud polimetalicznych ze względu na znaczne trudności. W artykule rozszerzono wykorzystanie teorii Lane’a poprzez propozycję modelu optymalizacji wartości granicznej surowca, zastosowanego do połączonych procesów górniczo-przeróbczych podziemnych kopalń rud polimetalicznych. Za pomocą modelu wizualizacji 3D zasobów i wykorzystaniu ekwiwalentnych współczynników określono funkcję celu wyrażoną jako jedną zmienną funkcję oceny wartości granicznej. Następnie konstruowane są krzywe przyrostu wartości aktualnej w stosunku do wartości granicznej dotyczące różnych ograniczeń zdolności produkcyjnych, a rozsądna wartość graniczna odpowiadająca każdemu ograniczeniu jest obliczana za pomocą metody wyszukiwania złotego odcinka. Zdefiniowane kryterium globalnej optymalizacji oceny granicznej określa się poprzez maksymalizację efektów ekonomicznych. Jako przykład do sprawdzenia proponowanego modelu w studium przypadku wykorzystano podziemne złoża polimetaliczne miedzi w Tybecie. Wyniki pokazują, że całkowita optymalna ekwiwalentna wartość graniczna, 0,28%, poprawia NPV o 170,2 milionów juanów w porównaniu z obecnie stosowaną oceną graniczną. Tak więc zastosowanie modelu optymalizacyjnego sprzyja osiągnięciu bardziej satysfakcjonujących korzyści ekonomicznych przy założeniu racjonalnego wykorzystania zasobów mineralnych.
Źródło:
Gospodarka Surowcami Mineralnymi; 2019, 35, 1; 25-42
0860-0953
Pojawia się w:
Gospodarka Surowcami Mineralnymi
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The properties of coupled waves propagating in long suspended cables
Własności sprzężonych fal rozprzestrzeniających się w linach o znacznej długości
Autorzy:
Snamina, J.
Powiązania:
https://bibliotekanauki.pl/articles/280708.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
long cables
coupled waves
dispersion relation
cut-off frequencies
Opis:
In this paper, the properties of coupled waves travelling along a long cable are analysed. Since the tension and curvature in the equilibrium position of the cable are slowly varying functions of the arc co-ordinate, the problems concerning the travelling waves can be solved using the Wentzel-Kramers-Brillouin (WKB) method. The waves propagating in the plane of the equilibrium curve are coupled. The wave associated with displacements perpendicular to the plane is uncoupled from the remaining waves. Applying the WKB method, the dispersion relation and equations describing the amplitudes of waves are determined. For a longitudinal-dominated pair of waves, there exist two cut-off frequencies depending on the arc co-ordinate. The results of calculations of wavelengths and amplitudes are presented in the form of plots.
W pracy przedstawiono analizę własności fal mechanicznych rozprzestrzeniających się w linach o znacznej długości. W liniowej teorii fale rozchodzące się w płaszczyźnie zwisu są ze sobą sprzężone, a fala wywołująca przemieszczenia punktów liny w kierunku prostopadłym do płaszczyzny zwisu rozprzestrzenia się niezależnie od pozostałych fal. W rozważaniach uwzględniono wolno-zmienną zależność siły osiowej i krzywizny od współrzędnej łukowej, w położeniu równowagi statycznej liny. Zagadnienia dotyczące przemieszczających się wzdłuż przewodu fal rozwiązano metodą WKB (Wentzel-Kramers-Brillouin).Wyznaczono związki dyspersyjne charakteryzujące ruch falowy w linach, wyprowadzono prędkości fazowe i grupowe z uwzględnieniem sprzężenia fal rozchodzących się w płaszczyźnie zwisu. Analizie poddano zależność liczb falowych oraz amplitud od współrzędnej łukowej. W rozważaniach wykorzystano symetrię ruchu fal. Wyniki obliczeń zostały zobrazowane na szeregu wykresach.
Źródło:
Journal of Theoretical and Applied Mechanics; 2008, 46, 4; 973-992
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of fly ashes on hardening slurries resistance to sulphate attack
Autorzy:
Kledyński, Z.
Powiązania:
https://bibliotekanauki.pl/articles/241464.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
groundwater protection
sulphate attack
cut-off walls
hardening \break slurries
Opis:
Rapid development of slurry wall technology in the underground constructions caused a noticeable increase in interest, cut-off walls well known in the past. Introduction of hardening slurry to this technology makes their construction easier and creates new possibilities for their application. Current challenge lies in subsoil insulation in order to avoid contamination spread into the ground waters. Thus, besides the already well known problems, new ones appeared, in that the issue of corrosion, especially of a chemical nature, to which the cut-off walls are exposed in the environment of aggressive groundwater. The paper focuses on the assessment of the hardening slurries to sulphate attack. The results of own investigations of cement-bentonite hardening slurry and cement-bentonite-ash hardening slurry prepared with the addition of aggressive liquid, as well as, with tap water and kept in a sulphate ion medium for 1 year are presented. Contamination spreading in non-filtration conditions was modelled. Tests of samples made with tap water and stored in tap water are considered as controls. The paper presents results of tests of liquid slurries properties and results of assessments of hardened slurries. Changes in mass of slurries, compressive and tensile strength and changes in sample storage environment chemistry were measured. Thermographic investigations of slurries were also conducted. The results of investigations and review of literature data on hardening slurries corrosion resistance to sulphate attack are presented. Practical suggestions in relation to the application of cut-off walls made of hardening slurries are made.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2004, 51, 2; 119-133
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł

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