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Tytuł:
Effect of geotextile reinforcement on shear strength of sandy soil: laboratory study
Autorzy:
Denine, S.
Della, N.
Muhammed, R. D.
Feia, S.
Canou, J.
Dupla, J.-C.
Powiązania:
https://bibliotekanauki.pl/articles/178921.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sand
behaviour
geotextile
undrained
confining pressure
excess pore pressure
strength ratio
Opis:
This paper presents results of a series of undrained monotonic compression tests on loose sand reinforced with geotextile mainly to study the effect of confining stress on the mechanical behaviour of geotextile reinforced sand. The triaxial tests were performed on reconstituted specimens of dry natural sand prepared at loose relative density (Dr = 30%) with and without geotextile layers and consolidated to three levels of confining pressures 50, 100 and 200 kPa, where different numbers and different arrangements of reinforcement layers were placed at different heights of the specimens (0, 1 and 2 layers). The behaviour of test specimens was presented and discussed. Test results showed that geotextile inclusion improves the mechanical behaviour of sand, a significant increase in the shear strength and cohesion value is obtained by adding up layers of reinforcement. Also, the results indicate that the strength ratio is more pronounced for samples which were subjected to low value of confining pressure. The obtained results reveal that high value of confining pressure can restrict the sand shear dilatancy and the more effect of reinforcement efficiently.
Źródło:
Studia Geotechnica et Mechanica; 2016, 38, 4; 3-13
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cell detection and tracking in lab-on-a-chip devices by image processing
Autorzy:
Lizanets, D.
Walczak, R.
Powiązania:
https://bibliotekanauki.pl/articles/174093.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
image processing
lab-on-a-chip
computer vision
bioanalysis
Opis:
This paper is devoted to the usage of image processing techniques in lab-on-a-chip devices for a cell detection and tracking. Advantages and disadvantages of image processing in data acquisition from lab-on-a-chip are described. A modified multiparametric object tracking method is presented. The method was tested on the lab-on-a-chip setup with living euglena and has shown plausible results for video with a low frame rate.
Źródło:
Optica Applicata; 2018, 48, 1; 15-24
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physicochemical mechanisms of mineral nanoparticles effects on pulmonary gas/liquid interface studied in model systems
Autorzy:
Kondej, D.
Sosnowski, T. R.
Powiązania:
https://bibliotekanauki.pl/articles/110409.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
inhalation
nanoparticles
gas-liquid interface
dynamic surface tension
Opis:
Inhaled mineral nanoparticles which are deposited on the lung surface may influence the gas/liquid barrier and the pulmonary surfactant (PS) which constitutes the vital element of the respiratory system. This research is focused on the physicochemical effects caused by selected clay nanoparticles (bentonite, halloysite, montmorillonites) interacting with PS and changing its original surface activity. Using three measuring methods (pulsating bubble technique, Langmuir balance and drop shape analysis), we demonstrated the influence of different mineral nanoparticles on the dynamic surface tension of animal-derived PS material (Survanta®) and main surfactant phospholipid (DPPC). The results which are dependent on material properties and concentration allow to hypothesize possible pathways of health effects from inhalation of mineral nanoparticles. This may help to set the guidelines in defining occupational safety standards and methods of protection of the respiratory system against inhaled mineral dusts.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 1; 57-69
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microbial transformations of fossil organic matter of kupferschiefer black shale – elements mobilization from metalloorganic compounds and metalloporphyrins by a community of indigenous microorganisms
Autorzy:
Matlakowska, R.
Ruszkowski, D.
Sklodowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/110373.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
black shale
fossil organic matter
metalloporphyrins
metalloorganic compounds
biotransformation
microbial community
Opis:
The presented article describes the role of community of indigenous microorganisms occurring in the Kupferschiefer black shale in elements mobilization from fossil organic matter of the deposit. The short description of metalloorganic compounds and metalloporphyrins extracted from black shale was presented as well as the characterization of indigenous microorganisms. The processes of fossil organic matter colonization, biofilm development and elements mobilization accompanying bacterial growth was summarized.
Źródło:
Physicochemical Problems of Mineral Processing; 2013, 49, 1; 223-231
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption kinetics of fluoride on bone char and its regeneration
Autorzy:
Hu, J.
Wu, D.
Rao, R.
Liu, R.
Lai, W.
Powiązania:
https://bibliotekanauki.pl/articles/206892.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
chlorine compounds
fluorine compounds
ions
sodium compounds
sulfur compounds
adsorption kinetics
chemical reaction equilibrium
correlation coefficient
Freundlich equation
optimal conditions
layered double hydroxides
aqueous-solution
drinking water
equilibrium
adsorbent
związki chloru
związki fluoru
jod
związki sodu
związki siarki
kinetyka adsorpcji
równowaga reakcji chemicznej
współczynnik korelacji
równanie Freundlicha
woda pitna
równanie Langmuira
Opis:
The adsorbent of bone char (BC), produced from the pyrolysis of crushed animal bones, was dominated by the mesopores of the Brunauer Emmett Teller (BET) surface area. The optimal condition for defluoridation with BC was a pH level near 5.0. Chloride and nitrate ions could increase fluoride adsorption capacity in contrast with the effect of sulfate and carbonate ions. The interchangeability between fluoride and hydroxyl groups on BC sorbent was proved by the Fourier transform infrared spectroscopy. Langmuir equation had a better correlation coefficient than the Freundlich equation at various temperatures. Thermodynamic parameters such as Delta G degrees, Delta H degrees, Delta S degrees, Ea and S*, have been calculated to describe the nature of fluoride adsorption onto BC. Negative Delta G degrees and Delta H degrees values at various temperatures indicate a spontaneous process, and its exothermic effect, respectively. However, a positive Delta S degrees value represents an increasing process for entropy. The E-a and S* values ranging from 5 to 40 kj.mol-1 and 0 to 1, respectively, demonstrated that the adsorption is dominated by physical process, although the adsorption kinetic process was involved external diffusion, intraparticle diffusion and chemical reaction equilibrium stage. A high concentration of NaOH solution increases efficiency of removing adsorbed F- ions from the BC surface.
Źródło:
Environment Protection Engineering; 2017, 43, 3; 93-112
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessing influence of hydrochloric acid leaching on structural changes and bleaching performance of Nigerian clay from Udi
Autorzy:
Ajemba, R. O.
Onukwuli, O. D.
Powiązania:
https://bibliotekanauki.pl/articles/110317.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
acid leaching
adsorption
bleaching
hydrochloric acid
isotherm
Opis:
Clay from Udi in Nigeria was mined, ground, and acid-leached at different concentrations of hydrochloric acid to produce adsorbents of varying properties. The raw and acid-leached samples were characterized using x-ray fluorescence (XRF) and Fourier transforms infra-red spectroscopy (FTIR) to examine the structural modifications in the clay as a result of acid-leaching. The analysis showed that the acid-leaching process caused several modifications of the clay samples. The surface area, Si/[Al + Fe + Mg] ratio, adsorption capacity were found to have increased in the acid-leached samples. The acid-leached samples were tested in order to ascertain their performance in bleaching palm oil and it was observed that the bleaching efficiency increased from 29.8% to 66.7%. The acid-leached sample prepared with 7M hydrochloric acid yielded an adsorbent that was efficient in bleaching palm oil under the experimental conditions. The isotherm analysis showed that the bleaching process followed the Freundlich equation.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 1; 349-358
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorptive removal of colour pigment from palm oil using acid activated nteje clay. Kinetics, equilibrium and thermodynamics
Autorzy:
Ajemba, R. O.
Onukwuli, O. D.
Powiązania:
https://bibliotekanauki.pl/articles/110649.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
adsorption
kinetics
isotherm
activation
colour pigment
palm oil
bleaching
Opis:
The kinetics of colour pigment removal from palm oil using acid activated clay from Nteje has been investigated. To determine the equilibrium adsorption capacity, the effects of temperature, contact time, adsorbent dosage and particle size were studied. The experimental adsorption data were analyzed using pseudo-first order, pseudo-second order, and Elovich kinetic models. The pseudo-second order model fitted very well to the kinetic experimental data. Equilibrium isotherms were analyzed by Lang-muir and Freundlich adsorption models. The data was in line with the Freundlich isotherm indicating a monolayer adsorption. The activation energy was calculated as 12 kJ/mol, and other thermodynamic parameters were determined as ΔS° = 0.063 J/mol, ΔH° = –34.994 J/mol, and ΔG° = –58.606 kJ/mol. These values indicate that the adsorption of colour pigment from palm oil onto acid activated clay was exothermic and can be attributed to physico-chemical adsorption process.
Źródło:
Physicochemical Problems of Mineral Processing; 2013, 49, 1; 369-381
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurements of AlGaN/GaN heterostructures for sensor applications
Autorzy:
Hojko, M R
Paszuk, D
Paszkiewicz, B
Powiązania:
https://bibliotekanauki.pl/articles/174545.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sensor
AlGaN/GaN heterostructure
electrolyte
two-dimensional electron gas (2DEG)
pH
Opis:
In the paper, the behavior of AlGaN/GaN HEMT-type heterostructures in a water solution of (KOH + HCl) with differing pH was studied. The influence of the electrolyte pH on channel pinch-off voltage was measured using impedance spectroscopy methods. It was observed that the change of the pH of electrolyte has a strong effect on the pinch-off voltage of AlGaN/GaN HEMT-type heterostructures independently of the concentration of other ions. In high-pH environment the so-called memory effect of heterostructures was revealed. Its possible origin was discussed. A general theory to explain all results was proposed.
Źródło:
Optica Applicata; 2013, 43, 1; 35-38
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterisation of nano-thin film GO/TiO2 layers for Kretschmann-based surface plasmon resonance visible sensing using FDTD method
Autorzy:
Khairulazdan, N. B.
Mohamed, R.
Berhanuddin, D. D.
Menon, P. S.
Powiązania:
https://bibliotekanauki.pl/articles/2033878.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
surface plasmon resonance
FDTD
titanium dioxide
graphene oxide
Kretschmann
biosensor
Opis:
Kretschmann-based surface plasmon resonance (K-SPR) is suitable for biomolecular sensing which provides label-free and quick detection results with real-time analysis. In this work, we have investigated the effect of graphene oxide (GO) with titanium dioxide (TiO2) thin films that are placed in hybrid above metal layers such as gold (Au), silver (Ag) and copper (Cu) with the presence of chromium (Cr) as an adhesive layer. The thickness of the Au, Ag and Cu metal thin films were optimized to 40, 30 and 30 nm, respectively, with a fixed thickness of GO of 2 nm and TiO2 of 1.9 nm. The sensing was evaluated for SPR excitation at three different visible wavelengths of 633, 670 and 785 nm. The performance of sensing was analyzed based on the reflectance intensity and full-width at half-maximum (FWHM) of the spectrum using the finite-difference time-domain (FDTD) method. The sensitivity was calculated for analyte sensing in dielectric mediums of air versus water. The sensitivity increment percentage (%∆S ) was determined when comparing analyte detection using Cr/metal and Cr/metal/GO/TiO2 sensor structures. The highest sensitivity of 94.51 deg/RIU was achieved for Cr/Cu/GO/TiO2 K-SPR sensor at 633 nm wavelength.
Źródło:
Optica Applicata; 2021, 51, 4; 579-587
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biofilter model development for the removal of pollutants from feedlot runoff
Autorzy:
Wan, H.
Wilson, B. N.
Schmidt, D. R.
Powiązania:
https://bibliotekanauki.pl/articles/207193.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
biofilters
parameter estimation
pollution
runoff
biofiltr
usuwanie zanieczyszczeń
MinnFARM
Opis:
Biofilters are a potential treatment option for removing pollutants from feedlot runoff but little research has been done on their use and design. In this study, two mechanism -based models were developed to simulate biofilter processes: a first-order model and a logistic model. The two models were calibrated and evaluated using nitrogen (N) and phosphorus (P) data collected from rainfall events for an experimental biofilter at Melrose, Minnesota, USA. The first-order model predicted removal efficiencies better than the logistic model. The sensitivity analysis suggested that the predictions of the first-order model are more sensitive to parameter. In addition, the uncertainty analysis suggested that the range in predictive errors could be a consequence of uncertainty of estimating parameter from the limited data set for the first-order model. In contrast, the uncertainty analysis for the logistic model of N suggested that reasons other than the uncertainty in parameter estimation are needed to explain predictive errors. Overall, the study provides a useful tool for assessing biofilter performance that can easily be improved with larger observed data sets. The biofilter model has been implemented in the most recent version of the Minnesota feedlot annualized runoff model (MinnFARM).
Źródło:
Environment Protection Engineering; 2017, 43, 3; 61-80
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy harvester based on Terfenol-D for low power devices
Autorzy:
Mech, R.
Kaleta, J.
Lewandowski, D.
Wiewiórski, P.
Powiązania:
https://bibliotekanauki.pl/articles/1190061.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
pozyskiwanie energii
mikrokontroler
materiał inteligentny
harvesting energy
low-power microcontroller
smart material
Opis:
Rising requirements for a new constructions, force engineers to monitor them all day long. An attractive solution seems to be applications of wireless sensors. However, there is a barrier limiting their application, which is the need to supply them with an electrical power over extended period of time without using additional wiring or batteries. The potential solution of this problem seems to be an energy harvesting. This paper proposes a new energy harvesting device based on magnetostrictive material. In the course of the experiments with using Terfenol-D rods as actuators and sensors it has been shown, that the mechanical impact to the magnetic core based on Terfenol-D rod, NdFeB permanent magnets and coil set allowed to obtain an electric power signal enough to supply device of 100 Ohm load on their active state.
Źródło:
Interdisciplinary Journal of Engineering Sciences; 2014, 2, 1; 8--12
2300-5874
Pojawia się w:
Interdisciplinary Journal of Engineering Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristic points and cycles in planar kinematics with application to the human gait
Autorzy:
Dathe, H.
Gezzi, R.
Kubein-Meesenburg, D.
Nägerl, H.
Powiązania:
https://bibliotekanauki.pl/articles/307506.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
kinematyka
ruch
chód
człowiek
automatic cycle choice
center of motion
planar kinematics
principle of least action
Opis:
Purpose: We present a novel method to process kinematical data typically coming from measurements of joints. This method will be illustrated through two examples. Methods: We adopt theoretical kinematics together with the principle of least action. We use motion and inverse motion for describing the whole experimental situation theoretically. Results: By using the principle of least action, the data contain information about inherent reference points, which we call characteristic points. These points are unique for direct and inverse motion. They may be viewed as centers of the fixed and moving reference systems. The respective actions of these characteristic points are analytically calculated. The sum of these actions defines the kinematical action. This sum is by design independent of the choice of reference system. The minimality of the kinematical action can be used again to select numerically one representative cycle in empirically given, approximately periodic motions. Finally, we illustrate the theoretical approach making use of two examples worked out, hinge movement and the sagittal component of the movement of a human leg during gait. Conclusions: This approach enables automatic cycle choices for evaluating large databases in order to compare and to distinguish empirically given movements. The procedure can be extended to three dimensional movements.
Źródło:
Acta of Bioengineering and Biomechanics; 2015, 17, 1; 75-86
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interactions of insoluble micro- and nanoparticles with the air-liquid interface of the model pulmonary fluids
Autorzy:
Dobrowolska, K.
Jabłczyńska, K.
Kondej, D.
Sosnowski, T. R.
Powiązania:
https://bibliotekanauki.pl/articles/110690.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
lung surfactant
pulmonary fluids
air-liquid interface
compressibility
nanoparticle
Opis:
The work discusses physicochemical phenomena related to interactions between the inhaled particles and the surface of pulmonary fluid which contains the lung surfactant. Dynamic surface phenomena which arise due to periodical variations of the interfacial area during breathing cycle are the extraordinary feature of this system and they are strictly related to the mechanics of ventilation and the pulmonary mass transfer processes. Presence of foreign material such as inhaled micro- and nanoparticles with different size, surface properties and morphology may alter these phenomena which may have some health consequences. This effect is discussed on two examples: mineral particles (CeO2) and carbonaceous particles emitted from diesel engine running on two different fuels. Two experimental methods of research in this field are presented: the Langmuir balance and the oscillating pendant drop. The results show the sensitivity of dynamic surface properties of the lung surfactant on exogenous materials which may be introduced to the respiratory system by inhalation of dusty air. Some physicochemical interpretation of these results is presented.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 1; 151-162
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study on heavy metals mobility from zinc plant residues in Iran
Autorzy:
Moradkhani, D.
Eskandari, S.
Sedaghat, B.
Najafabadi, M. R.
Powiązania:
https://bibliotekanauki.pl/articles/110826.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
heavy metals
zinc leaching plant
leaching filter cake
column leaching
Opis:
The transport of heavy metals from mining disposal site to groundwater and surface water is one of the most serious environmental problems in the world. The transport of heavy metals such as Zn, Cd and Mn from leaching filter cake in RECo, Zanjan, Iran was examined by using column leaching. Parameters studied included: flow rate, pH of input solution and leaching time. In this study, the maximum dissolution percents of Zn, Cd and Mn in input solution pH of 5 were 45.50 %, 53.97% and 19.94%, respectively. To statistically analysis the experimental results, SPSS14 software was employed. The results of SPSS 14 indicated that for the Zn, Cd and Mn dissolution, time and flow rate were found respectively, the effective parameters for the pollution in zinc leach residues.
Źródło:
Physicochemical Problems of Mineral Processing; 2013, 49, 2; 567-574
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improving the operation of the full scale wastewater treatment plant with use of a complex activated sludge model
Autorzy:
Liwarska-Bizukojc, E.
Biernacki, R.
Gendaszewska, D.
Ledakowicz, S.
Powiązania:
https://bibliotekanauki.pl/articles/207994.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
activated sludge
effluents
wastewater treatment
water treatment plants
biological waste water treatment
wastewater treatment plants
osad czynny
ścieki
stacje uzdatniania wody
biologiczne oczyszczanie ścieków
oczyszczalnie ścieków
Opis:
A complex activated sludge model implemented in BioWin software has been implemented to assure its predictability and improve the effectiveness of biological wastewater treatment in the full-scale plant in Poland. The influence of temperature and sludge retention time (SRT) on the quality of the effluent was also studied. The calibration was successfully performed according to the Good Modelling Practice Unified (GMP) protocol. Five parameters at a steady state and ten under dynamic conditions were calibrated. It occurred that in the studied wastewater treatment plant SRT should be kept at the low level sufficient to sustain nitrification.
Źródło:
Environment Protection Engineering; 2013, 39, 1; 183-195
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł

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