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Wyświetlanie 1-50 z 214
Tytuł:
Economic development and international and interregional tourism
Rozwój gospodarczy a turystyka międzynarodowa i międzyregionalna
Autorzy:
Zhang, W.-B.
Powiązania:
https://bibliotekanauki.pl/articles/2051177.pdf
Data publikacji:
2020
Wydawca:
Akademia Bialska Nauk Stosowanych im. Jana Pawła II w Białej Podlaskiej
Tematy:
interregional trade
international tourism
services
growth
wealth accumulation
Opis:
Subject and purpose of work: Tourism was the fastest growing industry until the outbreak of Covid-2019. Nevertheless, there are a few studies on how the industry interacts with the rest of economies within a comprehensive analytical framework. The main concern of this study is how international and interregional tourism interacts with national economic development and economic structural change. Tourism and economic growth are investigated in a multi-regional small open economy which is perfectly competitive. Materials and methods: National economy consists of multiple regions and each region has three sectors: industry, service, and housing. Production side is the same as in the neoclassical growth theory. Households move freely between regions, equalizing utility level between regions by selecting housing, goods, tourism, and saving. A region’s amenity is endogenously related to the region’s population. Results: We explicitly solve the dynamics of the multi-regional economy. The system has a unique stable equilibrium point. Conclusions: We simulate the motion of the model and examine the effects of changes in the rate of interest, foreigners’ preference for visiting a region, a region ‘s total productivity of the service sector, domestic consumers’ preference for visiting a region, as well as the propensity to save, the propensity to consume regional services and housing
Źródło:
Economic and Regional Studies; 2020, 13, 4; 375-387
2083-3725
2451-182X
Pojawia się w:
Economic and Regional Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation and experimental study in the process of wave energy conversion
Autorzy:
Zhang, W.
Liu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/260115.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
wave energy converter
suitable control technology
experimental verification
Opis:
This article introduces the operating principle of the wave energy device and makes AMEsim simulated analysis in the influence of the amplitude and period of the wave on the output efficient. By using the result of the simulation to optimize design, the article puts forwards a kind of suitable control technology which based on the disclosed amplitude and period of the wave to control the check valve, invoking the motor in different levels of efficiency. This kind of technology aims to solve the problem which includes low efficiency and high start wave of the wave energy device. The result is verified by the physical experiment, which lays the foundation for the implementation of marine engineering. The established methods of simulation model and analysis results are expected to be useful to designing and manufacturing of wave energy converter.
Źródło:
Polish Maritime Research; 2016, S 1; 123-130
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computer-aided model construction and database design of railway yard information
Autorzy:
Tang, Y.
Zhang, W.
Powiązania:
https://bibliotekanauki.pl/articles/223995.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
railway yard
information model
database
system development
kolej
baza danych
rozwój systemu
Opis:
Railway yard is the basic composition unit of railways, therefore, the efficiency and quality of railway yard design have a crucial effect on the construction and operation of railways. Plane design is the basis and core of railway yard design, consequently, it is significant to research plane design of railway yard. In this study, through analysis and summary of the research status as well as integrated application of computer technology and railway yard plane design methods, we researched and developed railway yard plane design system based on AutoCAD platform. According to the characteristics of railway yard plane design, we constructed the information model based on which we established specialized database, with the information data organized and managed efficiently; moreover, we put forward methods of constructing geometric models of the plane equipment, meanwhile, we did a focused research on associated design of yard equipment and preliminarily realized linkage design of planar yards.
Źródło:
Archives of Transport; 2016, 38, 2; 71-78
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flotation of lignite pretreated by sorbitan monooleate
Autorzy:
Zhang, W.
Tang, X.
Powiązania:
https://bibliotekanauki.pl/articles/109467.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sorbitan monooleate
flotation
lignite
FTIR
XPS
SEM
Opis:
In this study, sorbitan monooleate was used to pretreat lignite prior to flotation tests. First, the lignite sample and water were mixed with 0%, 0.5%, 1%, 1.5% and 2% (on the basis of the weight of the coal) of sorbitan monooleate to produce five types of flotation slurries. FTIR, XPS and SEM were used to analyze the surface properties of the lignite sample. The flotation tests were used to indicate the improvements in flotation of lignite after the sorbitan monooleate pre-treatment. FTIR and XPS results showed that there are many oxygenated functional groups in lignite such as carboxyl group and hydroxyl groups. Furthermore, SEM results showed that there are many holes on the lignite surface. These holes will be filled with water in the flotation pulp. The flotation results indicated that sorbitan monooleate can improve the lignite flotation at low concentrations of sorbitan monooleate. However, the flotation behavior of lignite deteriorated at higher concentrations of sorbitan monooleate.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 2; 759-766
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Performance Assessment of Heat Resistant Fabrics Based on a New Thermal Wave Model of Skin Heat Transfer
Autorzy:
Zhu, F.
Zhang, W.
Song, G.
Powiązania:
https://bibliotekanauki.pl/articles/90033.pdf
Data publikacji:
2006
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
thermal performance
skin burn
skin simulant sensor
heat resistant fabrics
thermal wave skin model
ciepło
temperatura skóry
oparzenie
Opis:
A thermal wave skin model incorporating surface heat flux from a skin simulant sensor is developed to characterize the thermal performance of heat resistant fabrics covering the skin simulant sensor. Comparisons of time to 2nd-degree skin burn and temperature elevation of skin beneath a layer of fabric between the Pennes’ equation and the newly developed thermal wave skin model are performed in this research. Results of tolerance time from the Stoll criterion method are also compared with those from 2 skin models in a thermal protective performance calorimeter. It is concluded that the thermal properties of heat resistant fabrics can be characterized more precisely than previously.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2006, 12, 1; 43-51
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of 50-year wind data of the Southern Baltic Sea for modelling coastal morphological evolution – a case study from the Darss-Zingst Peninsula
Autorzy:
Zhang, W.
Harff, J.
Schneider, R.
Powiązania:
https://bibliotekanauki.pl/articles/48896.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Baltic Sea
coastal morphological evolution
coastline change
Darss-Zingst Peninsula
modelling
morphodynamic model
sea level
statistical analysis
wind
wind direction
wind speed
Opis:
High-resolution wind series in the southern Baltic Sea for the period of 1958–2007 are analysed to generate representative climate input conditions for a multi-scale morphodynamic model to simulate decadal-to-centennial coastline change. Four seasonal wind classes, each characterized by a predominant distribution of wind direction and speed, are derived from statistical analysis. Further calibration of this statistical description is done by sensitivity studies of the model to generate similar coastline changes of the Darss-Zingst peninsula as the measured data for the last century. The coastline change of this area is then projected for the next 300 years based on four different climate scenarios, through which impacts of accelerated sea level rise and storm frequency on the long-term coastline change are quantified.
Źródło:
Oceanologia; 2011, 53, (1-TI)
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charging station location optimization of electric ship based on backup coverage model
Autorzy:
Zhang, W.
Yan, X.
Zhang, D.
Powiązania:
https://bibliotekanauki.pl/articles/117632.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
main engine
ship propulsion
charging station
electric ship
backup coverage model
electric ship energy
electric energy supply
ship charging station
Opis:
In terms of electric ship energy requirement in navigation, the ship charging station location is especially important. In this paper, a multi-period ship charging station location optimization model is pro-posed to make location decision in overall, from initial possible station sites chosen to the capacity determination for the final location sites. In the first phase, from the perspective of external environment, find out all possible ship charging station candidate sites through the feasible analyze. In the second phase, taking the ship charging demands into consideration, the final ship charging station sites can be selected among the candidate sites based on backup coverage model. In the last phase, regarding the cost of construction and service capability for different grade as the main factor in capacity determination, the optimal capacity of each final ship charging station are determined by means of optimization method. Finally, an example of Yanqi lake in China is used to verify the validity of the proposed methodology. The reasonable location of charging station could ensure the electric energy supply and avoid congestion caused by ship charging gathering. The model can be easily generalized to other problems regarding facility allocation based on user demand.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2017, 11, 2; 323-327
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagnosis of incipient faults in nonlinear analog circuits
Autorzy:
Deng, Y.
Shi, Y.
Zhang, W.
Powiązania:
https://bibliotekanauki.pl/articles/220611.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nonlinear circuits
fault diagnosis
Volterra series
fractional correlation
hidden Markov model (HMM)
Opis:
Considering the problem to diagnose incipient faults in nonlinear analog circuits, a novel approach based on fractional correlation is proposed and the application of the subband Volterra series is used in this paper. Firstly, the subband Volterra series is calculated from the input and output sequences of the circuit under test (CUT). Then the fractional correlation functions between the fault-free case and the incipient faulty cases of the CUT are derived. Using the feature vectors extracted from the fractional correlation functions, the hidden Markov model (HMM) is trained. Finally, the well-trained HMM is used to accomplish the incipient fault diagnosis. The simulations illustrate the proposed method and show its effectiveness in the incipient fault recognition capability.
Źródło:
Metrology and Measurement Systems; 2012, 19, 2; 203-218
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transmission characteristics of 85Rb and 87Rb laser-induced dichroism atomic filters at 795 nm
Autorzy:
Peng, Y F
Zhang, W J
Powiązania:
https://bibliotekanauki.pl/articles/173843.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
atomic filter
optical anisotropy
narrowband
rubidium
Opis:
The transmission characteristics for 85Rb and 87Rb laser-induced dichroism atomic filters operating on rubidium D1 lines (795 nm) transitions are analyzed. By means of semiclassical density matrix equations of motion, a three-level model for the transmission characteristics of the ground state laser-induced dichroism atomic filter is presented. Calculative results show that this filter, using two counterpropagating pump and probe beams, can obtain higher transmission, narrower bandwidth and larger tuning capability than that using two copropagating pump and probe beams; with the aid of counterpropagating pump, the 85Rb ground state laser-induced dichroism atomic filter can be more effective to achieve higher peak transmission (>34%) and larger tunability (>1 GHz) than the 87Rb ground state laser-induced dichroism atomic filter in the same operation parameters. This result may be helpful for improving peak transmission (14.6%) of Rb ground state laser-induced dichroism atomic filter reported (CERÈ A. et al., Opt. Lett. 34(7), 2009, pp. 1012–1014).
Źródło:
Optica Applicata; 2014, 44, 1; 55-67
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semi-analytical solution of optimization on moon-pool shaped WEC
Autorzy:
Zhang, W. C.
Liu, H. X.
Zhang, X. W.
Zhang, L.
Powiązania:
https://bibliotekanauki.pl/articles/963397.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
wave energy
eigenfunction expansion
moon pool
conversion ability
optimization
Opis:
In order to effectively extract and maximize the energy from ocean waves, a new kind of oscillating-body WEC (wave energy converter) with moon pool has been put forward. The main emphasis in this paper is placed on inserting the damping into the equation of heaving motion applied for a complex wave energy converter and expressions for velocity potential added mass, damping coefficients associated with exciting forces were derived by using eigenfunction expansion matching method. By using surface-wave hydrodynamics, the exact theoretical conditions were solved to allow the maximum energy to be absorbed from regular waves. To optimize the ability of the wave energy conversion, oscillating system models under different radius-ratios are calculated and comparatively analyzed. Numerical calculations indicated that the capture width reaches the maximum in the vicinity of the natural frequency and the new kind of oscillating-body WEC has a positive ability of wave energy conversion.
Źródło:
Polish Maritime Research; 2016, S 1; 25-31
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Observer-based fault-tolerant control against sensor failures for fuzzy systems with time delays
Autorzy:
Tong, S.
Yang, G.
Zhang, W.
Powiązania:
https://bibliotekanauki.pl/articles/930168.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
sterowanie rozmyte
sterowanie z opóźnieniem
obserwator stanu
sterowanie tolerujące uszkodzenia
liniowa nierówność macierzowa
analiza stateczności
fuzzy time delay systems
sensor faults
state observer
fault tolerant control
linear matrix inequalities
stability analysis
Opis:
This paper addresses the problems of robust fault estimation and fault-tolerant control for Takagi-Sugeno (T-S) fuzzy systems with time delays and unknown sensor faults. A fuzzy augmented state and fault observer is designed to achieve the system state and sensor fault estimates simultaneously. Furthermore, based on the information of on-line fault estimates, an observer-based dynamic output feedback fault-tolerant controller is developed to compensate for the effect of faults by stabilizing the resulting closed-loop system. Sufficient conditions for the existence of both a state observer and a fault-tolerant controller are given in terms of linear matrix inequalities. A simulation example is given to illustrate the effectiveness of the proposed approach.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2011, 21, 4; 617-627
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Friction Between Footwear and Floor Covered With Solid Particles Under Dry and Wet Conditions
Autorzy:
Li, K. W.
Meng, F.
Zhang, W.
Powiązania:
https://bibliotekanauki.pl/articles/90294.pdf
Data publikacji:
2014
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
slip & fall
friction measurement
solid contaminants
Brungraber Mark II
upadek
tarcie
podłoga
obuwie
Opis:
Solid particles on the floor, both dry and wet, are common but their effects on the friction on the floor were seldom discussed in the literature. In this study, friction measurements were conducted to test the effects of particle size of solid contaminants on the friction coefficient on the floor under footwear, floor, and surface conditions. The results supported the hypothesis that particle size of solids affected the friction coefficient and the effects depended on footwear, floor, and surface conditions. On dry surfaces, solid particles resulted in friction loss when the Neolite footwear pad was used. On the other hand, solid particles provided additional friction when measured with the ethylene vinyl acetate (EVA) footwear pad. On wet surfaces, introducing solid particles made the floors more slip-resistant and such effects depended on particle size. This study provides information for better understanding of the mechanism of slipping when solid contaminants are present.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2014, 20, 1; 43-53
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel method of handling tolerances for analog circuit fault diagnosis based on normal quotient distribution
Autorzy:
Ao, Y.
Shi, Y.
Zhang, W.
Li, X.
Powiązania:
https://bibliotekanauki.pl/articles/221119.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
soft-fault diagnosis
analog circuit
Normal Quotient Distribution
Slope Fault Model
Opis:
While the Slope Fault Model method can solve the soft-fault diagnosis problem in linear analog circuit effectively, the challenging tolerance problem is still unsolved. In this paper, a proposed Normal Quotient Distribution approach was combined with the Slope Fault Model to handle the tolerances problem in soft-fault diagnosis for analog circuit. Firstly, the principle of the Slope Fault Model is presented, and the huge computation of traditional Slope Fault Characteristic set was reduced greatly by the elimination of superfluous features. Several typical tolerance handling methods on the ground of the Slope Fault Model were compared. Then, the approximating distribution function of the Slope Fault Characteristic was deduced and sufficient conditions were given to improve the approximation accuracy. The monotonous and continuous mapping between Normal Quotient Distribution and standard normal distribution was proved. Thus the estimation formulas about the ranges of the Slope Fault Characteristic were deduced. After that, a new test-nodes selection algorithm based on the reduced Slope Fault Characteristic ranges set was designed. Finally, two numerical experiments were done to illustrate the proposed approach and demonstrate its effectiveness.
Źródło:
Metrology and Measurement Systems; 2012, 19, 4; 817-830
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ metabolitów form Tox grzyba Phoma lingam na kultury zarodków mikrosporowych oraz protoplastów rzepaku
Influence of Phoma lingam Tox fungal metabolites on oilseed rape microspore-derived embryo and protoplast cultures
Autorzy:
Zhang, W.
Kachlicki, P.
Cegielska, T.
Jedryczka, M.
Powiązania:
https://bibliotekanauki.pl/articles/834181.pdf
Data publikacji:
1998
Wydawca:
Instytut Hodowli i Aklimatyzacji Roślin
Źródło:
Rośliny Oleiste - Oilseed Crops; 1998, 19, 2
1233-8273
Pojawia się w:
Rośliny Oleiste - Oilseed Crops
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heating control of heated twin radiosonde humidity sensor based on DMC
Autorzy:
Sun, N.
Zhang, Y.
Zhang, W
Cheng, E.
Liu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/260018.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
DMC
twin heated humidity sensor
expanded responsible curve
heating control
Opis:
In order to effectively solve condensation and icing problems of radiosonde in low-temperature environment at high altitude, humidity sensor heated automatic alternately to remove pollution and improve the measurement accuracy. Heat experiments obtained the curve of rising temperature and responsible time on heated twin humidity sensor in normal temperature and pressure, by expanded responsible curve to obtain heated model of twin heated humidity sensor and by the analysis of heating model, use DMC and PID control for heating respectively. Simulation results show that the DMC control meets the practical requirements of measure at high altitude.
Źródło:
Polish Maritime Research; 2016, S 1; 52-58
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and simulative study on accumulator function in the process of wave energy conversion
Autorzy:
Zhang, W.
Liu, Y.
Luo, H.
Xue, G.
Zhang, J.
Powiązania:
https://bibliotekanauki.pl/articles/259862.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
wave energy converter
AMESim simulation
accumulator
experimental verification
Opis:
In this paper, a floating-buoy wave energy converter using hydrostatic transmission system is studied. The entire work progress of wave energy power generation device is introduced, and the hydraulic transmission principles are emphasized through the simulation to verify the feasibility of design principle of hydraulic transmission system. The mathematical model of the accumulator is established and applied in the AMEsim simulation. The simulation results show that the accumulator plays an important role in the wave power hydraulic transmission system and that the correct configuration of accumulator parameters can improve the rapidity and stability of the system work. Experimental results are compared with the simulation results to validate the correctness of the simulation results. This would provide a valuable reference to the optimal design of wave power generation.
Źródło:
Polish Maritime Research; 2016, 3; 79-85
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A sedimentation model for particulate suspensions in liquid–solid fluidized beds with inclined channels
Autorzy:
Li, Y.
Li, N.
Qi, X.
Zhang, W.
Zhu, R.
Powiązania:
https://bibliotekanauki.pl/articles/949735.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
suspension
fluidized bed
fluidization
inclined channel
inclined sedimentation
Opis:
The motion characteristics of mineral particles in a modified fluidized bed (mFB) with inclined plates have been studied both theoretically and experimentally. A particulate sedimentation model is built on the fluidization superficial velocity, terminal settling velocity, the device dimensions, the particle properties, and the volume fraction of the particulate suspensions in the inclined channel, which is to describe the motion behavior of particles in mono-disperse suspensions. The experimental particles are a mixture of silica and sand particles with the sizes in the range of 425 - 710 μm and 710 - 880 μm, respectively. Further, the model is extended to describe bi-disperse suspensions. The experimental system is established to be consistent with the theoretical arrangements, aiming to provide more accurate measurements. Specifically, the prediction results are in good agreement with the experimental data with the absolute deviation less than 11%. The results showed that the average solid volume fraction in the inclined channel fluctuates slightly for a given total solid inventory. The theoretical model is of certain practical significance for applications of this system to the classification, separation, and desliming of minerals.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 837-846
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on recovery of lead, zinc, iron from jarosite residues and simultaneous sulfur fixation by direct reduction
Autorzy:
Wang, Y.
Yang, H.
Zhang, W.
Song, R.
Jiang, B.
Powiązania:
https://bibliotekanauki.pl/articles/110933.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
jarosite
direct reduction
recovery
valuable metal
sulfur fixation
Opis:
Jarosite residues, which are generated in a zinc production plant by a hydrometallurgical process, contain a large amount of valuable metal components. In this study, a method was proposed for the recovery of lead, zinc and iron from the residues and simultaneous sulfur fixation through direct reduction followed by magnetic separation. The influences of the roasting temperature, roasting time and the concentration of SO2 gas in the direct reduction process were researched in detail. Results showed that the volatilization rates of lead, zinc and sulfur were 96.97%, 99.89% and 1.09%, respectively, and the iron metallization rate was 91.97% under optimal reduction conditions; roasting temperature 1523 K for 60 min. The magnetic concentrate with the iron content of 90.59% and recovery rate of 50.87% was obtained from the optimal reduction product by grinding and magnetic separation. The optimum fineness for separation 96.56% less than 37 μm accounted with magnetic field strength 24 kA/m. The theoretical analysis was carried out by thermodynamics, X-ray powder diffraction, gas analysis and scanning electron microscopy.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 2; 517-526
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Depth-resolved measurement of the compression displacement fields on the front and rear surfaces of an epoxy sample
Autorzy:
Zhang, W.
Dong, B.
He, Z.
Xie, S.
Zhou, Y.
Powiązania:
https://bibliotekanauki.pl/articles/174399.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
depth-resolved measurement
compression displacement field
wavenumber-scanning interferometry
epoxy
Opis:
Compression is one of the typical parameters measured in material mechanics. In this research, the compression displacement fields on the front and rear surfaces of an epoxy sample are measured by using a tilt depth-resolved wavenumber-scanning Michelson interferometer. The light source is a distributed feedback laser diode, the wavenumber of which can be modulated to about 1.017 × 104 m–1 by the temperature without mode hopping. A random-sampling Fourier transform is designed to evaluate the phase differences before and after the applied loads. Experimental results show that the depth-resolved measurement of the compression displacement field is of high accuracy. It can be used to analyze force propagation inside resin-based composites.
Źródło:
Optica Applicata; 2018, 48, 2; 311-323
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study and numerical simulation on fly ash separation with different plate voltages in rotary triboelectrostatic separator
Autorzy:
Zhang, L.
Tao, Y.
Tao, D.
Zhang, W.
Yang, L.
Powiązania:
https://bibliotekanauki.pl/articles/110712.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fly ash
rotary triboelectrostatic separator
plate voltage
numerical simulation
Opis:
As the main solid wastes of coal-fired power plants, fly ash particles with different electrical properties are usually recycled using triboelectrostatic separator. The purpose of this study was to investigate the effect of different plate voltages on the separation of fly ash in a rotary triboelectrostatic separator with experiments and numerical simulation. The maximum values of yield of ash products (48.30%), and decarbonisation rate (50.89%) and the minimum loss-on-ignition (6.61%) were obtained when the plate voltage was 24 kV in the separation experiments, while 55.98%, 59.46%, 5.80% were reached respectively when the plate voltage was 26 kV in the simulation. In general, experimental data were similar with numerical simulation. The turning points appeared around 25 kV due to the increasing mismatch in products, which resulted from the reinforced rebound phenomena, namely the charged particle rebound from the electrode plate with a larger reflection velocity, when the plate voltage increased from 18 to 28 kV. It was validated by the numerical simulation results.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 722-731
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the State of Internal Stress and Strain of TATB-based Polymer Bonded Explosive Using Strain Markers and Cone-Beam Computed Tomography
Autorzy:
Dai, B.
Lan, L.-G.
Zhang, W.-B.
Tian, Y.
Powiązania:
https://bibliotekanauki.pl/articles/358613.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
technology of materials
testing and analysis
compression molding
polymer bonded explosive
stress state
strain ellipsoid
X-ray tomography
Opis:
Precise measurement of the inner structural strain of polymer bonded explosive (PBXs) granules during compression molding is highly desirable in order to investigate the inner stress distribution field and its underlying generation mechanism, with the aim of improving the stress distribution uniformity. In this contribution, TATB-based (1,3,5-triamino-2,4,6-trinitrobenzene) PBX granules were formulated and the stress-strain state of the PBX granules during the warm molding process was analyzed. Strain markers were implanted at different locations and the deformation characteristics and regularity of the embedded spherical strain markers were obtained by X-ray micro-tomography. Thus the local strain states at different locations could be obtained, and the local stress state could be deduced. The results showed that axisymmetric deformation occurred in all of the strain markers, where the flat strain ellipsoids were mainly compressed uni-axially. In the central region, the stress was mainly in an axial direction, and the shear force was small. Not only axial stresses, but also large shear stresses in the surrounding region of the cylindrical grains were present. The stress gradient in the central region was greater than that in the surrounding region. The stress was greater in the surrounding region because this region was squeezed by the mold. The maximum strain degree was 44.8% larger than the minimum strain degree. The local stress increment in each region was quantified. The stress increments of the three axes were in the range 14.2-19.5 MPa. This study examined the feasibility of evaluating the inner stress–strain state of PBX granules in a quantitative manner, which is significant in determining the inner strain and stress distribution in PBX granules during the molding process.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 3; 688-707
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal configurations of wave energy converter arrays with a floating body
Autorzy:
Zhang, W.
Liu, H.
Zhang, X.
Zhang, L.
Ashraf, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/260084.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
wave energy
cylinder array
power take-off
hydrodynamic analysis
Opis:
An array of floating point-absorbing wave energy converters (WECs) is usually employed for extracting efficiently ocean wave energy. For deep water environment, it is more feasible and convenient to connect the absorbers array with a floating body, such as a semi-submersible bottom-moored disk, whose function is to act as the virtual seabed. In the present work, an array of identical floating symmetrically distributed cylinders in a coaxial moored disk as a wave energy device is proposed The power take-off (PTO) system in the wave energy device is assumed to be composed of a linear/nonlinear damper activated by the buoys heaving motion. Hydrodynamic analysis of the examined floating system is implemented in frequency domain. Hydrodynamic interferences between the oscillating bodies are accounted for in the corresponding coupled equations. The array layouts under the constraint of the disk, incidence wave directions, separating distance between the absorbers and the PTO damping are considered to optimize this kind of WECs. Numerical results with regular waves are presented and discussed for the axisymmetric system utilizing heave mode with these interaction factors, in terms of a specific numbers of cylinders and expected power production.
Źródło:
Polish Maritime Research; 2016, S 1; 71-77
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Expansion of Explosive Molecular Crystals: Anisotropy and Molecular Stacking
Autorzy:
Qian, W.
Zhang, C.
Xiong, Y.
Zong, H.
Zhang, W.
Shu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/358262.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
energetic material
anisotropic thermal expansion
molecular stacking
molecular dynamics simulation
density functional theory method
Opis:
Molecular dynamics simulations of three typical explosive crystals, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 1,1-diamino-2,2- dinitroethene (FOX-7) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), were carried out under NPT ensemble and selected force field. The equilibrium structures at elevated temperatures were obtained, which show that the stacking behaviour of the molecules does not change with temperature. The coefficient of thermal expansion (CTE) values were calculated by linear fitting methods, and the results show that the CTE values are close to the experimental results and are anisotropic. The total energies of the cells expanding along each single crystallographic axis were calculated by the periodic density functional theory method, indicating that the energy change rates are anisotropic, and correlation equations of the energy change vs. CTE values were established. The essence of the anisotropy of the explosive crystal’s thermal expansion was compared and elucidated.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 1; 59-81
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the breakthrough phenomena during heavy metal elution from a column packed with municipal waste incineration ash
Autorzy:
Zhang, W.
Yang, Y.
Suganuma, H.
Kato, S.
Suzuki, S.
Kojima, T.
Powiązania:
https://bibliotekanauki.pl/articles/206904.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
calcium compounds
dissolution
heavy metals
leaching
particle size
związki wapnia
rozpuszczanie
metale ciężkie
ługowanie
wielkość cząstek
Opis:
At some point during acid leaching column tests of heavy metals from municipal waste incineration ash, sudden and rapid elution of harmful elements was observed which was called the breakthrough (BT) phenomena. The mechanism was elucidated from the results of measurement of elemental and particle size distribution in the column and batch leaching tests as follows. At the first stage of experimental runs, CaCO3 was dissolved in acidic solution and pH profile along the bed is formed. Some of the minor elements of Zn and Al dissolved by acid at the upper part of the column are precipitated at bottom of the column, leading to the reduction of flow rate of the leachate solution. After leachate pH becomes low by the termination of dissolution of Ca, these deposits are dissolved and thus, the flow rate increases. Most of the trace elements behave as such, which causes the increase of harmful element concentrations in the eluate. Some drastic concentration increase of harmful elements in leachate may occur even after the long period of pseudo stable dissolution behavior in the land-fill site.
Źródło:
Environment Protection Engineering; 2018, 44, 3; 63-78
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal design and numerical simulation on fish-like flexible hydrofoil propeller
Autorzy:
Xue, G.
Liu, Y.
Zhang, M.
Zhang, W.
Zhang, J.
Luo, H.
Jia, R.
Powiązania:
https://bibliotekanauki.pl/articles/259984.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
bionics
flexible hydrofoil
phase angle
hydrodynamic coefficient
Opis:
Hydrofoil is widely used in underwater vehicle for the excellent hydrodynamic characteristics. Currently, researches are mostly about the rigid hydrofoil while the flexible hydrofoil, like the caudal fin, has not been studied adequately. In this paper, the fish was regarded as the bionic object. Then the kinematics model to describe the fish swimming was put forward. A fin-peduncle propulsion mechanism was designed based on the kinematics model to achieve the similar sine curve swimming model. The propulsion mechanism was optimized by Matlab to reduc the deviation between the output curve of the fin-peduncle propulsion mechanism and the ideal motion trajectory. Moreover, the motion phase angles among flexible articulations are optimized to reduce fluid resistance and improve propulsive efficiency. Finally, the fish-like hydrofoil oscillation is simulated by fluid-solid coupling method based on the Fluent. It was shown that the optimized flexible fish-like oscillation could generate the motion that follows the similar law of sine. The propulsive efficiency of oscillating hydrofoil propeller is much higher than that of the screw propeller, and the flexible oscillation has higher propulsive efficiency than the rigid oscillation without obvious fluid resistance increase.
Źródło:
Polish Maritime Research; 2016, 4; 59-66
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fibre Number of the Cross-section of Ringspun Yarn and its Strength Prediction Model
Liczba włókien w przekroju poprzecznym przędzy obrączkowej i model dla przewidywania jej wytrzymałości
Autorzy:
Zhang, H. W.
Li, Y. L.
Powiązania:
https://bibliotekanauki.pl/articles/232277.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
ring-spun yarn
yarn incross section
fibre number
yarn twist
yarn strength predication model
przędza obrączkowa
wytrzymałość przędzy
model wytrzymałości przędzy obrączkowej
masa liniowa
Opis:
A calculation equation of the fibre number on the cross-section of ring-spun yarn was deduced theoretically and verified with test data of 20 representative pure cotton ring spun yarns. The equation is practical and convenient to use by substituting the yarn count, yarn twist, and fibre decitex. On the basis of the above equation, a yarn strength predication model was established. The revising functions of yarn count and twist to yarn strength were deduced in practical tests of the strength of 20 commonly used ring-spun yarns, and were used to revise the yarn strength predication model obtained. Substituting the fibre decitex, fibre strength, yarn count, yarn twist and yarn strength can be precisely calculated with this model.
Przeprowadzając teoretyczne rozważania autorzy opracowali matematyczny wzór dotyczący liczby włókien w przekroju poprzecznym przędzy obrączkowej. We wzorze tym uwzględnili oddziaływanie: kształtu przekroju poprzecznego włókien i przędzy, masy liniowej włókien i przędzy, gęstości właściwej włókien i przędzy. Zaproponowane równanie pozwala projektować zamienniki przędzy pod względem ich masy liniowej (tex), liczby skrętu i masy liniowej włókien (tex). Traktując rozpatrywane równanie jako punkt wyjścia autorzy opracowali model przewidywania wytrzymałości przędzy. Otrzymane zależności teoretyczne zweryfikowano poprzez badania eksperymentalne. Przebadano 20 powszechnie stosowanych przędz obrączkowych. Opracowane modele pozwalają precyzyjnie obliczyć wytrzymałość przędzy obrączkowej.
Źródło:
Fibres & Textiles in Eastern Europe; 2014, 6 (108); 38-40
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transcriptomic landscape of Dendrobium huoshanense and its genes related to polysaccharide biosynthesis
Autorzy:
Han, R.
Xie, D.
Tong, X.
Zhang, W.
Liu, G.
Peng, D.
Yu, N.
Powiązania:
https://bibliotekanauki.pl/articles/57911.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Botaniczne
Opis:
Dendrobium huoshanense has long been used to treat various diseases in oriental medicine. In order to study its gene expression profile, transcripts involved in the biosynthesis of precursors of polysaccharides, as well as mechanisms underlining morphological differences between wild and cultivated plants, three organs of both wild type and cultivated D. huoshanense were collected and sequenced by Illumina HiSeq4000 platform, yielding 919,409,540 raw reads in FASTQ format. After Trinity de novo assembly and quality control, 241,242 nonredundant contigs with the average length of 967.5 bp were generated. qRT-PCR experiment on the selected transcripts showed the transcriptomic data were reliable. BLASTx was conducted against NR, SwissProt, String, Pfam, and KEGG. Gene ontology annotation revealed more than 40,000 contigs assigned to catalytic activity and metabolic process, suggesting its dynamic physiological activities. By searching KEGG pathway, six genes potentially involved in mannose biosynthetic pathway were retrieved. Gene expression analysis for stems between wild and cultivated D. huoshanense resulted in 956 genes differentially expressed. Simple sequence repeats (SSRs) analysis revealed 143 SSRs with the unit size of 4 and 3,437 SSRs the size of 3. The obtained SSRs are the potential molecular markers for discriminating distinct cultivars of D. huoshanense.
Źródło:
Acta Societatis Botanicorum Poloniae; 2018, 87, 1
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel method for 3D measurement of RFID multi-tag network using a machine vision system
Autorzy:
Zhuang, X.
Yu, X.
Zhao, Z.
Zhang, W.
Liu, Z.
Lu, D.
Dong, D.
Powiązania:
https://bibliotekanauki.pl/articles/221058.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
3D measurement
RFID multi-tag network
dual-CCD system
neural network
machine vision
Opis:
The three-dimensional (3D) coordinate measurement of radio frequency identification (RFID) multi-tag networks is one of the important issues in the field of RFID, which affects the reading performance of RFID multi-tag networks. In this paper, a novel method for 3D coordinate measurement of RFID multi-tag networks is proposed. A dual-CCD system (vertical and horizontal cameras) is used to obtain images of RFID multi-tag networks from different angles. The iterative threshold segmentation and the morphological filtering method are used to process the images. The template matching method is respectively used to determine the two-dimensional (2D) coordinate and the vertical coordinate of each tag. After that, the 3D coordinate of each tag is obtained. Finally, a back-propagation (BP) neural network is used to model the nonlinear relationship between the RFID multi-tag network and the corresponding reading distance. The BP neural network can predict the reading distances of unknown tag groups and find out the optimal distribution structure of the tag groups corresponding to the maximum reading distance. In the future work, the corresponding in-depth research on the neural network to adjust the distribution of tags will be done.
Źródło:
Metrology and Measurement Systems; 2018, 25, 3; 475-486
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Knitted silk mesh-like scaffold incorporated with sponge-like regenerated silk fibroin/collagen I and seeded with mesenchymal stem cells for repairing Achilles tendon in rabbits
Autorzy:
Tang, L.
Yang, Y.
Li, Y.
Yang, G.
Luo, T.
Xue, Y.
Zhang, W.
Powiązania:
https://bibliotekanauki.pl/articles/306523.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
ścięgno Achillesa
kolagen
komórki macierzyste
szpik kostny
Bombyx mori silk
regenerated silk fibroin
collagen I
bone marrow-derived mesenchymal stem cells
weft-knit
Achilles tendon action
Opis:
A scaffold knit with natural sericin-free silk fibroin fiber possesses desirable mechanical properties, biocompatibility, ease of fabrication, and slow degradability. However, regenerated silk fibroin degrades faster than natural silk. In this study, natural silk fibroin fiber mesh-like scaffolds were prepared by a weft-knitting method and the pores were filled with sponge-like regenerated silk fibroin-collagen I. The microporous sponge and mesh-like scaffolds were fused to achieve gradient degradation of the scaffolds, and rabbit bone marrow mesenchymal stem cells (BMSCs) were seeded onto the scaffolds to form scaffold–BMSCs composites. The composites were implanted into gap defects made in the rabbit Achilles tendon. Twenty weeks after implantation, histological observation showed that tendon-like tissue had formed, collagen I mRNA was expressed, abundant collagen was generated, and that there was no obvious degradation of silk. The maximum load of the neo-Achilles tendon was 62.14% that of the natural Achilles tendon. These outcomes were superior to those obtained in the group implanted with a scaffold without BMSCs. These findings suggest the feasibility of constructing tissue-engineered tendons using weft-knitted silk scaffolds incorporated with sponge-like regenerated silk fibroin/collagen I and seeded with BMSCs, and show potential of the scaffold–BMSCs composites to repair Achilles tendon defects.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 3; 77-87
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification and expression of GA-related genes associated with in vitro micro-tubers formation in Pinellia ternata
Autorzy:
Xue, T.
Yue, E.
Chao, E.
Su, Y.
Zhang, W.
Zhu, Y.
Teng, J.
Xue, J.
Powiązania:
https://bibliotekanauki.pl/articles/11872893.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Opis:
Pinellia ternata is one of the most important herbs in traditional Chinese medicine. Recently, its yield is hard to meet the market demand, therefore the system of in vitro micro-tubers was developed for its propagation and endogenous GA was revealed probably function negatively during micro-tubers induction. However, the mechanism is still unknown. In this study, 70 mg/L chlormequat chloride (CCC) was successfully used to inhibit the endogenous GA content and promote the micro-tubers induction. Subsequently, suppression subtractive hybridization (SSH) was performed to identify GA-related genes associated with in vitro micro-tubers formation in P. ternata. The cDNAs of micro-tubers induced with and without CCC were used as the “tester”, and “driver”, respectively. SSH library sequencing yielded 300 expressed sequence tags (ESTs). Finally, 226 ESTs were retained after screening, 84 of which had no significant homology to any of previously identified genes and 39 of the remaining 142 ESTs represented singletons. Real-time quantitative RT-PCR analysis of the expression patterns showed that all 5 transcripts showed signal alteration during the process of in vitro micro-tubers formation. The sequences appeared to be highly homologous with 60S ribosomal protein, 26S ribosomal RNA gene, zinc transporter protein, 12kD storage protein and malate dehydrogenase, respectively. These results would facilitate the functional characterization of the GA-related genes associated with in vitro micro-tubers development and subsequent in vitro manipulation.
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2018, 17, 6; 85-94
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Characterization of a High Energy Combustion Agent (BHN) and Its Effects on the Combustion Properties of Fuel Rich Solid Rocket Propellants
Autorzy:
Pang, W.-Q.
Zhao, F.-Q.
Xue, Y.-N.
Xu, H.-X.
Fan, X.-Z.
Xie, W.-X.
Zhang, W.
Lv, J.
Deluca, L. T.
Powiązania:
https://bibliotekanauki.pl/articles/358474.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
fuel rich solid propellant
BHN
DSC
TG-DTG
burning rate
combustion properties
Opis:
A high energy combustion agent (tetraethylammonium decahydrodecaborate, BHN) was prepared by means of an ion exchange reaction (IER), and the prepared samples were characterized by the advanced diagnostic techniques of Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC) etc. The effects of BHN particles on the hazard and combustion properties of fuel rich solid propellants were investigated. The results showed that the BHN samples and fuel rich propellants containing BHN particles can be prepared successfully and solidified safely. The peak temperature of thermal decomposition and the heat of decomposition of the BHN samples prepared were 305.8 °C and 210.9 J•g-1 at a heating rate of 10 K•min-1, respectively. The burning rate and pressure exponent of fuel rich solid propellants decreases with increases in the fraction of BHN particles in the propellant formulation. Compared with the reference formulation (sample BP-1), the burning rate of the propellant with 10% mass fraction of BHN particles (sample BP-4) had decreased 30% at 3.0 MPa, and the pressure exponent had dropped from 0.44 to 0.41.
Źródło:
Central European Journal of Energetic Materials; 2015, 12, 3; 537-552
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Laboratory investigation of self-healing properties on geosynthetic clay liners with flaw
Autorzy:
Zhang, G.-W.
Zhang, H.-Y.
Wang, J.-F.
Zhou, L.
Liu, P.
Jiang, X.
Powiązania:
https://bibliotekanauki.pl/articles/204652.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
landfills
geosynthetic clay liner
self healing
hydraulic conductivity
Opis:
The objective of this paper is to evaluate the self- healing properties of a commercially-available geosynthetic clay liner (GCL) using flexible-wall permeameter. The GCLs are produced by the same factory, but the contents of bentonite are different. Also the hydraulic conductivities (HC) of GCLs with no defect are different. In this study, specimens were completely saturated under the backpressure of 20 kPa before the test. Permeability tests were performed on GCL specimens with penet rating flaw and also on specimens permeated with distilled water and CaCl2 solutions. The test results were presented and discussed. Experimental results showed that the GCL with penetrating flaw did not exhibit complete self-healing in the case of flaw. After 120 days, the hydraulic conductivity increased by approximately an order of magnitude. In addition, CaCl2 solutions had a significant influence on the hydraulic conductivity. The research findings might be of interest to researchers and engineers who design liners for landfills and other liquid containment facilities.
Źródło:
Archives of Environmental Protection; 2015, 41, 1; 53-58
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of nitrogen injection displacement for fire extinguishment
Zwalczanie pożarów endogenicznych za pomocą azotu
Autorzy:
Tang, Q.
Qin, R. X.
Chen, Q. H.
Zhang, G. S.
Powiązania:
https://bibliotekanauki.pl/articles/348639.pdf
Data publikacji:
2012
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
technologia ochrony przeciwpożarowej w szczelnych zrobach
technologia ochrony przeciw pożarowej metodą wtrysku gazów szlachetnych
technologia zwalczania pożarów za pomocą azotu
technologia separacji
nowe rozwiązania w technologii ochrony pożarowej
fire-prevented technology in sealed gob
fire-prevented technology by infusing inert gases
infusing-permuting nitrogen technology
separation technology
new development in fire-prevented technology
Opis:
The article introduced the basic theory of nitrogen injection displacement for fire extinguish, which is presented by Professor Guoshu Zhang, applied this technology in coal mine, and then verified the results through numerical simulation, the production got from the technology's application. Presented some new views in specific implementation of nitrogen injection displacement for fire extinguish.
W niniejszym artykule opisano zastosowanie podstawowej teorii wypełniania zrobów azotem podczas gaszenia pożarów endogenicznych zaprezentowanej przez profesora Guoshu Zhang, jej zastosowanie w kopalni oraz weryfikację wyników za pomocą symulacji numerycznej i uzyskane efekty w związku z zastosowaniem tej technologii. Zaprezentowano szczegółowe zasady oraz poglądy na temat wypełniania zrobów azotem do zwalczania pożarów.
Źródło:
AGH Journal of Mining and Geoengineering; 2012, 36, 3; 345-351
1732-6702
Pojawia się w:
AGH Journal of Mining and Geoengineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energetic Nitrogen-rich Salts
Autorzy:
Wu, J.-W.
Zhang, J.-G.
Zhang, T.-L.
Yang, L.
Powiązania:
https://bibliotekanauki.pl/articles/358479.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
energetic salts
synthesis
characterization
crystal structure
review
Opis:
Energetic salts as a unique class of energetic materials have recently been investigated widely, since they possess advantages over their atomically similar nonionic analogues – they tend to exhibit lower vapor pressures, higher densities and better thermal stabilities. Furthermore, these salts are readily improved upon by the appropriate combination of different cations and anions. Over the last twenty years, our group has continued to synthesize and study novel ionic energetic materials. Here, we have summarized all of the series of nitrogen-rich energetic salts. This review gives an overview of the various studies dealing with synthetic aspects and some of the physicochemical properties of ionic compounds that are based on ammonia, guanidine, semicarbazide, carbohydrazide, tetrazine, tetrazole, triazole and imidazole. In addition, their potential applications in the fields of explosives and propellants are discussed. We hope these investigations will be helpful in providing a wider insight for future research in the area of energetic salts.
Źródło:
Central European Journal of Energetic Materials; 2015, 12, 3; 417-437
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Morphology of the invasive amphiphyte Alternanthera philoxeroides under different water levels and nitrogen concentrations
Autorzy:
Ding, W.
Zhang, H.
Zhang, F.
Wang, L.
Cui, S.
Powiązania:
https://bibliotekanauki.pl/articles/19911.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Źródło:
Acta Biologica Cracoviensia. Series Botanica; 2014, 56, 2
0001-5296
Pojawia się w:
Acta Biologica Cracoviensia. Series Botanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prawo porównawcze w Chinach
Comparative Law in China
Autorzy:
Zhang, Lihong
Powiązania:
https://bibliotekanauki.pl/articles/518808.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Jagielloński. Fundacja Utriusque Iuris
Opis:
The Chinese defeat in the 1840 Sino-British Opium War led to the publication and diffusion of many Western books in China. More and more Chinese people realised that the prosperity of the West was not only based on its military power, but also on its advanced political and legal system. As a result, the Chinese began realising the importance of study of foreign laws and comparative implications thereof with Chinese law. The 1911 Revolution put an end to the 2000 years of feudal rule. The period between 1911 and 1949 saw a development of comparative law of which the main peculiarity was a strong objective to model of the Western capitalist countries. Legal research and study on comparative law in this period made an important progress and contributed significantly to the modernization of modern Chinese law. Between 1949 to the early 1960s the development of comparative law was constrained. The Cultural Revolution was dominated by the prevalence of legal nihilism, resulting in a halt to all legal study and research. Starting from 1990s the Chinese legislature has moved, first tentatively, then comprehensively, to espouse successful foreign legislative experiences. Current comparative legal research and development in Mainland China has undergone great progress and contributed significantly to the modernization of the Chinese legal system, but it still falls behind in comparison to other countries since it is still difficult for Chinese scholars to have access to first-hand, unprocessed materials and information.
Źródło:
Forum Prawnicze; 2014, 5 (25); 3-15
2081-688X
Pojawia się w:
Forum Prawnicze
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ship route planning using historical trajectories derived from AIS Data
Autorzy:
He, Y. K.
Zhang, D.
Zhang, J. F.
Zhang, M. Y.
Li, T. W.
Powiązania:
https://bibliotekanauki.pl/articles/116536.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
AIS Data
Automatic Identification System (AIS)
route planning
historical trajectories
AIS messages
marine traffic
Dijkstra algorithm
ant colony algorithm
Opis:
Ship route planning is one of the key issues in enhancing traffic safety and efficiency. Many route planning methods have been developed, but most of them are based on the information from charts. This paper proposes a method to generate shipping routes based on historical ship tracks. The ship's historical route information was obtained by processing the AIS data. From which the ship turning point was extracted and clustered as nodes. The ant colony algorithm was used to generate the optimize route. The ship AIS data of the Three Gorges dam area was selected as a case study. The ships’ optimized route was generated, and further compared with the actual ship's navigation trajectory. The results indicate that there is space of improvement for some of the trajectories, especially near the turning areas.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2019, 13, 1; 69-76
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EGTA, a calcium chelator, affects cell cycle and increases DNA methylation in root tips of Triticum aestivum L.
Autorzy:
Zhang, C.
Shi, W.
Ma, K.
Li, H.
Zhang, F.
Powiązania:
https://bibliotekanauki.pl/articles/57455.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Botaniczne
Opis:
In this study, when germinated Triticum aestivum L. seeds were treated with 0, 2, 4 and 6 mM ethyl glycol tetraacetic acid (EGTA), root growth was suppressed and the mitotic index decreased. These inhibitory effects were positively correlated with EGTA concentration. RT-PCR analysis revealed that the expression of several gene markers related to the G1/S transition of the cell cycle were significantly downregulated. Confocal microscopy of Fluo-3/AM-stained roots showed chelation of nearly all of the Ca2+ within the root meristematic regions. Both random amplified polymorphic DNA (RAPD) and coupled restriction enzyme digestion-random amplification (CRED-RA) techniques showed significant increases in the levels of genomic DNA polymorphisms and degree of DNA methylation. The study provides information concerning the impact of Ca²+) chelator, EGTA, on the growth, expression of cell cycle transition marker genes, and changes in DNA structure and methylation in the wheat roots.
Źródło:
Acta Societatis Botanicorum Poloniae; 2016, 85, 3
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zhang Yimou – twórca niezależny, twórca koniunkturalny? Metamorfozy artysty w państwie komunistycznym
Zhang Yimou – independent director or supporter of the state? One artist’s metamorphosis in a communist country
Autorzy:
Bachora, Łukasz
Gustin, Masa
Powiązania:
https://bibliotekanauki.pl/articles/664460.pdf
Data publikacji:
2019-12-20
Wydawca:
Uniwersytet Gdański. Wydawnictwo Uniwersytetu Gdańskiego
Opis:
This article describes how different attitudes towards reality develop as a result of living under a communist regime that undergoes dynamic economic and social transformation. The main focus is placed on Zhang Yimou, the renowned Chinese director, whose life and work seem to reflect on-going changes in a unique way,  showing a pattern closely correlated with the political and social situation in China. The author describes how two major revolutions, the Cultural Revolution and the following economic transformation of China, shaped the life of Zhang and influenced his work. When analyzed in depth, his movies form cycles which coincide with the rapidly changing social and political circumstances. Three such cycles are described: an independent movie-making stage, developing around the early stages of economic transformation and the events in Tiananmen Square in 1989; an intermediate stage related to the development of a new, semi-capitalist society in the nineties; and finally, a commercial stage related to the great economic boom of the first decade of the twenty-first century.
Źródło:
Gdańskie Studia Azji Wschodniej; 2019, 16; 110-127
2353-8724
Pojawia się w:
Gdańskie Studia Azji Wschodniej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Serological and molecular evidence of Coxiella burnetii in samples from humans and animals in China
Autorzy:
El-Mahallawy, H.S.
Kelly, P.
Zhang, J.
Yang, Y.
Wei, L.
Tian, L.
Fan, W.
Zhang, Z.
Wang, C.
Powiązania:
https://bibliotekanauki.pl/articles/49293.pdf
Data publikacji:
2016
Wydawca:
Instytut Medycyny Wsi
Źródło:
Annals of Agricultural and Environmental Medicine; 2016, 23, 1
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability based analysis and design of a tripod offshore wind turbine structure assuring serviceability performance
Autorzy:
Zhang, J.
Kang, W. H.
Zhang, C.
Sun, K.
Powiązania:
https://bibliotekanauki.pl/articles/259493.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
offshore wind turbine
tripod foundation
serviceability limit state
statistical correlation analysis
reliability analysis
Opis:
Typical tripod foundations are designed using deterministic computational models according to relevant standards and codes. However, for more cost-safety balanced design, uncertainties in significant parameters should be considered in preliminary design to ensure meeting a specific probabilistic safety target in the context of the complex configuration of a tripod structure. In this article, uncertainties associated with design parameters and modelling errors are considered using Monte Carlo simulations, in order to determine the key structural design parameters, and to determine the optimal balance between design parameters and design requirements. A Spearman rank-order correlation based analysis is carried out to understand the effects of design variables on maximum deformation, total weight, and natural frequency, and to have insight about important design parameters for improvement of a preliminary design. It is found that the tower diameter has the most significant effect on the maximum displacement on the hub as validated through engineering case studies. In addition, a statistical framework, which identifies influential design parameters and provides reliability evaluation, is proposed for the structural design of a tripod OWT system. The design cases considered in this study indicate that a simple deterministic design check cannot guarantee the required reliability level of the structure, and the cost-safety balance can be achieved by a reliability analysis with the consideration of the uncertainties in the structure.
Źródło:
Polish Maritime Research; 2018, 4; 139-148
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thriller w Xianie
Autorzy:
Czarnecki, Łukasz.
Powiązania:
Mówią Wieki 2020, nr 2, s. 50-54
Data publikacji:
2020
Tematy:
Zhāng Xuéliáng (1901-2001)
Komunizm
Wojsko
Zamach stanu
Artykuł z czasopisma historycznego
Opis:
Artykuł przybliża sytuację w Chinach po śmierci Yuan Shikaia i po zamachu stanu w 1936 roku dokonanego przez Zhang Xueliang’a. Przedstawiono porwanie generała Czang Kaj-szeka, przywódcy Kuomintangu.
Dostawca treści:
Bibliografia CBW
Artykuł
Tytuł:
Adaptive partition-based logic simulation using GPGPU
Autorzy:
Zhang, M.
Zhang, Y
Yang, W.
Kai, Y.
Wei, T.
Fan, X.
Powiązania:
https://bibliotekanauki.pl/articles/398148.pdf
Data publikacji:
2011
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
symulacja logiczna
obliczenia strumieniowe
GPGPU
obliczenia ogólnego przeznaczenia na układach GPU
CUDA
EDA
Automatyzacja procesu projektowania systemów elektronicznych
logic simulation
stream computing
Opis:
With the improvement of the gate complexity, the verification overhead becomes more decisive for VLSI design cost In order to reduce the simulation time, a adaptive partition based parallel method of VLSI logic simulation with GPGPU is addressed in this paper. The numerous arithmetic blocks of GPGPU is utilized simultaneously for disparate circuit macros. The partition strategy we proposed shows a sufficient flexibility to balance the different work load in parallel threads and fit the feature of GPU architecture. To explore the parallelism and locality of logic simulation further, the circuit macro is organized as stream data. The data dependency between the input and output nets in one individual logical path is handled with the shared memory of GPGPU. As for different logical paths, the dependency is processed by threads synchronization. To illustrate the performance, a serial experiments is implemented in Intel CoreDuo workstation with Nvidia GTX465 GPU board. Four typical digital circuits (LDPC, DES3, OpenRISC 1200 and OpenSPARCPARC T1) are considered as the benchmark. The result of experiments demonstrate a significant speed-up is achieved by using GPGPU parallel method, comparing with the CPU serial logic simulation. In maximal case (OpenS T1), the GPGPU parallel acceleration computes 21 times faster than serial program.
Źródło:
International Journal of Microelectronics and Computer Science; 2011, 2, 4; 121-128
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solution of some problems of single-scale wavelet transform processor using a magnetostatic surface wave device
Autorzy:
Lu, W.
Kuang, L.
Lü, X.
Zhu, C.
Zhang, T.
Zhang, J.
Powiązania:
https://bibliotekanauki.pl/articles/221174.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wavelet transform processor
magnetostatic surface wave (MSSW)
interdigital transducer
direct coupling
insertion loss
Opis:
In this paper, we investigate the implementation schemes of a single-scale wavelet transform processor using magnetostatic surface wave (MSSW) devices. There are three implementation schemes: the interdigital transducer, the meander line transducer and the grating transducer. Because the interdigital transducer has excellent properties, namely, good frequency characteristic and low insertion loss, we use the interdigital transducer as the implementation scheme of a single-scale wavelet transform processor using MSSW device. In the paper, we also present the solutions to the three key problems: the direct coupling between the input transducer and the output transducer, the insertion loss, and the loss characteristics of the gyromagnetic film having an influence on the wavelet transform processor. There are two methods of reducing the direct coupling between the input transducer and the output transducer: increasing the distance between the input transducer and the output transducer, and placing a metal "wall" between the input transducer and the output transducer. There also are two methods of reducing the insertion loss of a single-scale wavelet transform processor using a MSSW device for scale: the appropriate thickness of the yttrium iron garnet (YIG) film and the uniform magnetic field. The smaller the ferromagnetic resonance linewidth of the gyromagnetic film, the smaller the magnetostatic wave propagation loss.
Źródło:
Metrology and Measurement Systems; 2012, 19, 4; 685-692
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of preparation method on the performance of PtSn/Al2O3 &enspcatalysts for acetic acid hydrogenation
Autorzy:
Zhang, K.
Zhang, H.
Ma, H.
Ying, W.
Fang, D.
Powiązania:
https://bibliotekanauki.pl/articles/779525.pdf
Data publikacji:
2015
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Pt-Sn catalysts
preparation method
acetic acid hydrogenation
XPS
CO-FTIR
Opis:
PtSn/Al2O3 &enspcatalysts with a given loading of 1 wt% Pt and 1 wt% Sn were prepared by co-impregnation or successive impregnation with aqueous solutions of Pt, Sn precursors and a commercial alumina. The catalysts were characterized by N2 &enspadsorption, H2-TPR (H2&ensp temperature-programmed reduction), H2-pulse chemisorption, XPS (X-ray photoelectron spectroscopy) and CO-FTIR (Fourier transform infrared spectroscopy), and tested in the hydrogenation of acetic acid. The results showed that the preparation method affected both the chemical properties and their performance in the hydrogenation of acetic acid. Sn enrichment on the catalysts surface was observed on the co-impregnated catalyst and catalyst in which the Pt precursor had been loaded first. It was found that the modification of Pt was a function of the sequence of Sn addition as revealed by CO-FTIR. Co-impregnated catalyst showed the highest activity and ethanol selectivity.
Źródło:
Polish Journal of Chemical Technology; 2015, 17, 1; 11-17
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Occupational daily walking steps have inverse relationship with papillary thyroid cancer risk and progression: a retrospective analysis
Autorzy:
Zhang, Chunling
Zhang, Li
Su, Yan
Xiang, Lei
Zhang, Qin
Zhang, Chunhong
Huan, Qin
Powiązania:
https://bibliotekanauki.pl/articles/28761990.pdf
Data publikacji:
2024-03-05
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
biochemical markers
office workers
construction workers
papillary thyroid cancer
daily step counts
PTC stages
Opis:
Objectives Investigate the impact of daily occupational walking steps on the progression of papillary thyroid cancer (PTC), a topic hitherto underresearched. Material and Methods The authors analyzed the data from 800 individuals with PTC across stages 0–IV. Participants were evenly divided into 2 distinct occupational groups: office workers and construction workers (N = 400 each). Data included comprehensive records of daily walking steps, demographic information, and clinical indicators. Pearson’s correlation coefficients or analysis of variance (ANOVA) were employed to assess the linkage between daily walking steps and PTC risk and stage, as well as associated biochemical markers. Results The analysis revealed a significant inverse relationship between daily walking steps and PTC risk. A higher frequency of daily steps was associated with reduced chances of PTC onset and a lower diagnostic stage of the disease. This protective effect of physical activity was particularly pronounced in the construction worker cohort. Subsequent evaluations showed that construction workers who consistently logged higher daily steps had markedly lower levels of thyroid-stimulating hormone (TSH), free triiodothyronine, free thyroxine, thyroid peroxidase antibody, thyroglobulin antibody, and thyroglobulin (Tg). Notably, daily walking steps exhibited a strong inverse correlation with body mass index (BMI), age, PTC volumes, and levels of TSH and Tg across both occupational groups (ρ < –0.37). The increase in daily steps was associated with the reduction in PTC stages (p < 0.001). Conclusions The research underscores the potential benefits of increased daily walking steps, suggesting that they may play a protective role in reducing PTC risk and moderating its progression.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2024, 37, 1; 58-71
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal control strategy for marine SSP podded propulsion motor based on strong tracking-EPF
Autorzy:
Yao, W.
Liu, Y.
Sun, H.
Zhang, G.
Zhang, J.
Zhou, M.
Sun, M.
Jiang, D.
Powiązania:
https://bibliotekanauki.pl/articles/258784.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
marine electric propulsion
EPF
ST-EPF
SSP podded propulsion
propulsion motor
Opis:
Aiming at the non-linearity of state equation and observation equation of SSP (Siemen Schottel Propulsor) propulsion motor, an improved particle filter algorithm based on strong tracking extent Kalman filter (ST-EKF) was presented, and it was imported into the marine SSP propulsion motor control system. The strong tracking filter was used to update particles in the new algorithm and produce importance densities. As a result, the problems of particle degeneracy and sample impoverishment were ameliorated, the propulsion motor states and the rotor resistance were estimated simultaneously using strong track filter (STF), and the tracking ability of marine SSP propulsion motor control system was improved. Simulation result shown that the improved EPF algorithm was not only improving the prediction accuracy of the motor states and the rotor resistance, but also it can satisfy the requirement of navigation in harbor. It had the better accuracy than EPF algorithm.
Źródło:
Polish Maritime Research; 2015, S 1; 4-9
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Studies on Charging Operation of a Compact Repetitive Tesla Transformer
Autorzy:
Zhang, Z.
Zhang, J.
Yang, H.
Qian, B.
Meng, Z.
Li, D.
Wang, S.
Cao, Y.
Zhou, W.
Powiązania:
https://bibliotekanauki.pl/articles/1807860.pdf
Data publikacji:
2009-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
84.30.Ng
84.30.Jc
84.30.Qi
84.70.+p
Opis:
Charging operations of a compact Tesla transformer were experimentally investigated, in single-shot and rep-rate (50 pps for 1 s) modes, respectively. The charging limitations were also explored. The experimental results were compared and analyzed. The maximum secondary charging voltages of the Tesla transformer were measured to be 380 kV and 300 kV in single-shot and rep-rate modes, respectively. The RMS pulse-to-pulse instability of the secondary charging voltage is generally less than 10% but increases with the increasing initial voltage across the primary capacitor. Since the secondary capacitor of the Tesla transformer is a pulse forming line (PFL), continued operation is possible if there is breakdown in the PFL. Furthermore, operation can even be continued under occasional breakdown for some pulses, without the effects on the operations of subsequent pulses.
Źródło:
Acta Physica Polonica A; 2009, 115, 6; 973-975
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensitivity analysis of Kozeny-Carman and Ergun equations
Autorzy:
Sobieski, W.
Zhang, Q.
Powiązania:
https://bibliotekanauki.pl/articles/297987.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
porous media
Kozeny-Carman
Ergun
porosity
tortuosity
Opis:
In the article a sensitivity analysis of linear and nonlinear terms in the Kozeny-Carman and Ergun equations was shown. In the first case the impact of the porosity, tortuosity, specific surface of the porous body and the model constant was investigated. In the second case the porosity, the particle diameter and the sphericity function were taken into account. To express the model sensitivity by numbers, an earlier developed method was used. In this way the order and the importance of the impact of individual parameters was determined. The motivations to create this article were questions, which occurred during developing a novel investigation method, linking the Discrete Element Method and the CFD techniques. The first aim was to predict what will happen, if individual parameters will be set with an error: which data should be set as accurately as possible and which data are not very important for the result value. The second intention was to state which of parameters used in porous media investigations should be expressed by functions and which by constant values. The article may be treated as set of pointers helping in using of Kozeny-Carman and Ergun laws or as an example of research methodology based on the sensitivity analysis.
Źródło:
Technical Sciences / University of Warmia and Mazury in Olsztyn; 2014, 17(3); 235-248
1505-4675
2083-4527
Pojawia się w:
Technical Sciences / University of Warmia and Mazury in Olsztyn
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of stress-relief effects of protective layer extraction
Symulacja numeryczna skutków odprężenia warstwy zabezpieczającej w trakcie jej wybierania
Autorzy:
Jia, T.
Zhang, Z.
Tang, C.
Zhang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/219293.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
warstwa ochronna
odprężanie
symulacje numeryczne
strefa wycieku
protective layer
stress relief
numerical simulation
leakage zones
Opis:
Field test and laboratory analog model test on the stress-relief effects of protective layer extraction are time-consuming and laborious. In this paper, on the basis of full consideration of rock heterogeinity and in combination with gas geology at Pingdingshan Mine 5, a numerical model was estalished with the gas-solid coupling rock failure process analysis system RFPA-Gas to simulate the stress variation law, roof and floor deformation, fracture evolution law, displacement in the protected seam, change in gas permeability and gas migration law during protective layer extraction. The simulation results repoduced stress variations in coal and rock strata, roof and floor deformation and fracture evolution process during protective layer extraction. The movement of rock strata were characterized by upper three zones and lower two zones: caving zone, fracture zone and bending subsidence zone in the vertical direction in the overlying strata; floor deformation and failure zone and elasto-plastic deformation zone in the vertical direction in the underlying strata. It showed that stress relief occurred in the protected seam, which led to vertical and horizontal displacements, significant increase in gas permeability, gas desorption and migration. Hence, the outburst threat in the protected seam was eliminated. Meanwhile, with comprehensive analysis of variaition of stress state, deformation characteristics and fracture distribution in coal seam and with consideration of changes in gas leakage rate, gas pressure and permeability, according to gas leakage rate, the floor strata of the protecive layer were divided into four leakage zones. They corresponded to four zones with different stress states and fracture development: original leakage zone - slow reducing leakage zone - dramatic increasing leakage zone- steady increasing leakage zone. This classification provides a clear direction for gas control in the protective layer. The simulation results are in good agreement with the stress-relief effects in field.
Badania terenowe oraz modelowanie w warunkach laboratoryjnych skutków odprężenia warstwy zabezpieczającej w trakcie wydobycia są niezwykle czasochłonne i skomplikowane. Uwzględniając niejednorodność skał i wykorzystując dane geologiczne i o obecności gazów w kopalni Pindingshan 5, opracowano model numeryczny pękania skał w układzie gaz-ciało stałe w oparciu o analizę układu RFPA-Gaz. Model wykorzystano do symulacji zmian naprężeń, odkształceń stropu i spągu, propagacji pęknięć, przemieszczeń w pokładach zabezpieczonych, zmian w przepuszczalności gazów oraz migracji gazów w trakcie wybierania warstwy zabezpieczającej. Wyniki symulacji odwzorowują zmiany naprężeń, odkształceń stropu i spągu, propagacji pęknięć w trakcie wybierania warstwy ochronnej. Ruchy warstw górotworu scharakteryzowano poprzez analizę trzech stref nadkładu i dwóch stref lezących poniżej: w warstwach nadkładu: strefy zawału, strefy spękań oraz strefy osiadania (przemieszczenia w kierunku pionowym), w warstwach leżących poniżej: strefy odkształcenia i pękania spągu, oraz strefy odkształceń elastyczno- plastycznych w kierunku pionowym. Wykazano, że odprężanie miało miejsce w pokładzie zabezpieczającym, co prowadziło do powstania przemieszczeń pionowych oraz poziomych, zanotowano także znaczny wzrost przepuszczalności gazów, desorpcji gazów oraz ich transportu. Z tych względów zagrożenie wybuchem w pokładzie ochronnym zostało wyeliminowane. Całościowa analiza zmian stanu naprężenia, charakterystyki odkształceń i rozkładu pęknięć w pokładzie węgla przeprowadzona została dla czterech stref przecieku gazów, wydzielonych w oparciu zmiany natężenia wypływu gazów, ciśnienia gazów oraz przepuszczalności w odniesieniu do natężenia przepływu gazu w spągu w warstwie ochronnej. Te cztery strefy odpowiadały czterem strefom w których zanotowano odmienne stany naprężeń i rozkładu spękań: pierwotna strefa wycieku, powoli zmniejszająca się strefa wycieku, gramatycznie powiększająca się strefa wycieku i stopniowo powiększająca się strefa wycieku. Powyższa klasyfikacja dostarcza wyraźnych wytycznych dla prowadzenia kontroli wycieku gazu w warstwach ochronnych. Wyniki symulacji skutków odprężania wykazują dużą zgodność z wynikami badań terenowych.
Źródło:
Archives of Mining Sciences; 2013, 58, 2; 521-540
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-50 z 214

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