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Tytuł:
Forest in Karst Mountain sinkhole of southeastern China provides refugium for the preservation of bryophyte diversity
Autorzy:
Li, X.
Zhang, Z.
Wang, Z.
Shi, K.
Powiązania:
https://bibliotekanauki.pl/articles/2130582.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
negative landform
natural refuge
complex microenvironment
karst rocky
desertification
Opis:
The negative landform of sinkholes provides belowground level refugia for a high diversity of forest species compared to the forests on the surface of surrounding karst plateaus in southeastern China. Bryophyte diversity in sinkhole forests is also likely to be high. In this study, bryophytes of an underground forest sinkhole (UFS), and two forests (Forest Karst Mountain 1; FKM1) and (Forest Karst Mountain 2; FKM2) on the surface of the karst plateau were compared to understand the role of the sinkhole forest in the conservation of bryophyte diversity and the relationships between bryophyte diversity, environmental factors, and soil nutrients. Significantly more bryophyte taxa were recorded from the sinkhole forest (71 taxa, 36 genera, 23 families) than those in the forest on the plateau surface, which was the closest to the sinkhole (FKM1; 29 bryophyte taxa, 16 genera, 12 families), and even fewer bryophytes were found in the forest more distant to the sinkhole (FKM2; 22 taxa, 17 genera, eight families). Twenty-four liverwort taxa were collected from the sinkhole forest, two from the closest surface forest (FKM1) and none from the furthest surface forest (FKM2). Ninety-three percent of the bryophytes in karst mountain sinkhole were not found on surface forest. The diversity index trend was as follows: UFS > FKM1 > FKM2, and the evenness index trend was in the opposite direction as follows: UFS < FKM1 < FKM2. The beta diversity showed that the Jaccard index among the three forests was 0–0.25, reflecting a huge difference between the sinkhole forest and the two surface forests. Canonical correspondence analysis showed that light was the most important factor affecting the distribution of bryophytes in the sinkhole forest, while temperature and humidity were key factors for the distribution of bryophytes in the two surface forests. Further, soil parameters, namely, soil organic carbon, total nitrogen, total phosphorus, total potassium, alkali- hydrolyzed nitrogen, and available phosphorus changed gradually from UFS to FKM1 and to FKM2. The sinkhole forest, located in a landform with the unique negative topography enclosed by cliffs, and with a complex microenvironment, provides a natural refuge for bryophyte species in areas where forests have been negatively impacted by karst rocky desertification.
Źródło:
Acta Societatis Botanicorum Poloniae; 2020, 89, 4
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Salicylic acid induces physiological and biochemical changes in peony under waterlogging stress
Autorzy:
Zhu, X.
Shi, H.
Li, X.
Jin, S.
Powiązania:
https://bibliotekanauki.pl/articles/12703759.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Opis:
In this study, the effects of salicylic acid to antioxidative activity and photosynthetic characteristics in waterlogging stress of two peony cultivars (‘Fengdanbai’ and ‘Mingxing’) were investigated. 4-year-old peony grown in different levels of waterlogging stress and then different concentration prepared SA (0.0, 0.1, 0.5 and 1.0 mmol L⁻¹) sprayed on fresh leaves of peony. The antioxidative enzymes activities include superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), chlorophyll content, relative conductivity and MDA content were measured in leaves about different waterlogging treatment, the photosynthetic characteristics were also measured using photosynthetic measurement system. The results showed that waterlogging stress decreased the chlorophyll content in all peony cultivars leaves, but with SA treatment can inhibit the decrease of chlorophyll content. Relative conductivity increased as the extension of waterlogging time in two cultivars. SA treatment could effectively inhibit the increase of relative conductivity, and 0.5 mmol L⁻¹ of SA was the most suitable concentration. SOD, POD, CAT activity increased first and then decreased in different waterlogging condition, SA significantly increased the activity of various enzymes. MDA content was increase as the expansion of waterlogging time in two cultivars. SA inhibits the increase of MDA content. Of all concentration of SA, 0.5 mmol L⁻¹ was the best concentration to inhibit the waterlogging stress. For the photosynthetic characteristics, the net assimilation rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) and intercellular CO₂ (Ci) were decreased under different waterlogging condition. SA treatment can increase Pn, Gs, Tr and Ci of peony.
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2020, 19, 1; 41-52
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Digital control system design for bearingless permanent magnet synchronous motors
Autorzy:
Sun, X.
Shi, Z.
Yang, Z.
Wang, S.
Su, B.
Chen, L.
Li, K.
Powiązania:
https://bibliotekanauki.pl/articles/202311.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
BPMSMs
cyfrowy system kontroli
podwójnie zamknięty system regulacji prędkości
projektowanie oprogramowania
projekt sprzętu
digital control system
double-closed speed regulating system
software design
hardware design
Opis:
This study investigates a digital control system which is used in bearingless permanent magnet synchronous motors (BPMSMs). Compared with traditional permanent magnet synchronous motors, a BPMSM is characterized by higher speed and no mechanic friction. Therefore, the application value of the latter to the special area is higher than that of the former. An analysis from previous work on the BPMSM had proved its feasibility, and some performances such as suspension force, inductance and so on were also investigated. Based on this analysis, this study focuses on solving control problems in practical applications by designing a control system. The control system design includes overall schematic, hardware and software designs. Main software systems, including the force/current transform module and closed loop control module for radial displacement, are analyzed. Interface circuit for radial displacement, current feedback circuit and dead zone protection circuit are designed for the hardware system. Finally, several performance experiments have been conducted to verify the effectiveness of the designed digital control system. Experiment results indicate that the rotor has unique characteristics, such as stable suspension performance, good start-of-suspension performance, and rapid anti-disturbance features.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 5; 687-698
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Characterization of Metal Derivatives of 1,1,2,2-Tetranitraminoethane (TNAE)
Autorzy:
Zhu, C.
Meng, Z.
Xu, Z.
Liu, W.
Liu, Y.
Shi, X.
Xie, T.
Powiązania:
https://bibliotekanauki.pl/articles/358571.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
Ionic compound
1,1,2,2-tetranitraminoethane
thermal property
safety performance
thermal decomposition kinetics
Opis:
The introduction of anions and cations into energetic materials can significantly improve their physicochemical and energetic properties. The K, Zn, Ba, Cu and Pb salts of 1,1,2,2-tetranitraminoethane (TNAE) were synthesized using TNAE as the starting material, and were characterized by IR spectroscopy, NMR spectroscopy and elemental analysis. All of the energetic salts exhibited relatively high thermal stabilities (decomposition temperatures ranging from 195.1 °C to 279.3 °C) and high densities (ranging from 2.1 g·cm–3 to 3.7 g·cm–3). It was demonstrated that the introduction of metal ions conveys better thermal stability than covalent TNAE itself. More importantly, the Zn, Ba and Cu salts exhibited good thermal stability, high density, low sensitivity, and therefore have the potential to be a new class of insensitive, highly energetic explosives for practical applications.
Źródło:
Central European Journal of Energetic Materials; 2018, 15, 3; 435-444
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of bubble-particle interactions in a column flotation process
Autorzy:
Cheng, G.
Shi, C.
Yan, X.
Zhang, Z.
Xu, H.
Lu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/109635.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
particle
bubble
column flotation
collision
attachment
detachment
Opis:
Bubble-particle interactions play an important role in flotation. This study examines the behaviour of bubble clusters in a turbulent flotation cell. Particularly, the bubble-particle interaction characteristics in flotation are investigated. The bubble size in a flotation column was measured using an Olympus i-SPEED 3 high-speed camera. Relationships between the circulating volume, bubble size and bubble terminal velocity were discussed. Probabilities of collision, attachment, detachment and acquisition between bubbles and particles in different circulating volumes were calculated based on the flotation kinetic theory. Using the extended Derjaguin–Landau–Verwey–Overbeek (EDLVO) theory, the relationship between the potential energy and distance in bubble-particle interaction was analysed. The results demonstrated that as the circulating volume increased, the bubble size and velocity decreased. When the circulating volume increased from 0.253 to 0.495 m3/h, the bubble diameter decreased from 511 to 462 μm, and the corresponding bubble velocity decreased from 43.1 to 37.5 mm/s. When the circulating volume remained constant as the particle size increased, probabilities of collision, attachment, detachment and acquisition increased. When the particle size remained constant as the circulating volume increased, these probabilities also increased. At a constant circulating volume as the particle size increased, the absolute value of the total potential energy between the particle and bubble increased. When the distance between the bubble and particle was 30 nm, the energy barrier appeared.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 1; 17-33
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biomass partition and carbon storage of Cunninghamia lanceolata chronosequence plantations in Dabie Mountains in East China
Autorzy:
Xie, X.
Cui, J.
Shi, W.
Liu, X.
Tao, X.
Wang, Q.
Xu, X.N.
Powiązania:
https://bibliotekanauki.pl/articles/41359.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
biomass
carbon storage
Cunninghamia lanceolata
Chinese fir
chronosequence
plantation forest
Dabie Mountains
China
Opis:
The quantification of biomass carbon pools is important for understanding carbon cycling in forest ecosystems. This study was designed to reveal the effects of stand age on biomass partitioning and carbon storage of Chinese fir plantation stands in Dabie Mountains of Anhui, East China. A total of six even-aged Chinese fir plantation stands along an age-sequence from 10 to 50 years were selected. To quantify the biomass of different tree components, 18 trees with diameter at breast height (D1.3) from 6.5 to 35.2 cm were harvested from the different aged stands. Biomasses of understory vegetation, forest floor and standing dead trees were also investigated. Total biomass carbon storages ranged from 57.6 to 211.4 Mg ha–1 in the different aged stands. Tree layer comprised from 93.7% to 96.4% of the total biomass C pools in the different aged stands. The C pools of the necromass were from 1.8 to 6.2 Mg ha–1. Stand age had a significant effect on tree biomass partitioning, with an increase in proportion of root biomass. The root/shoot ratios were from 0.187 to 0.312, which was significantly positively correlated to stand age. The existing plantation stands are still developing and have somewhat high rate of biomass and carbon accumulations beyond the normal rotation period (usually 25–30 years) even over an age of 50 years. Appropriate prolongation of the rotation period of Chinese fir plantation will be effective in maintaining long-term productivity and providing large carbon sink. The measurements provide valuable data for modelling productivity of Chinese fir plantation forest.
Źródło:
Dendrobiology; 2016, 76
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Health index synthetization and remaining useful life estimation for turbofan engines based on run-to-failure datasets
Synteza wskaźników stanu technicznego oraz ocena pozostałego okresu użytkowania silników turbowentylatorowych z wykorzystaniem zbiorów danych o pracy do czasu uszkodzenia
Autorzy:
Shi, J.
Li, Y.
Wang, G.
Li, X.
Powiązania:
https://bibliotekanauki.pl/articles/301447.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
hierarchical clustering
relevance vector machine
run-to-failure
remaining useful life
health indices
prognostics
grupowanie hierarchiczne
maszyna wektorów istotnych
praca do czasu uszkodzenia
pozostały okres użytkowania
wskaźnik stanu technicznego
prognostyka
Opis:
Turbofan engines will gradually degrade until failure occurs or life ends if without maintenance. Reliable degradation assessment and remaining useful life (RUL) estimation make sense on both aviation safety and rational maintenance decisions. This paper proposes a data-driven prognostic method on the premise of run-to-failure (RtF) data which are multivariate sensory data collected from the engines operating from normal to failure. After necessary pre-processing to the data, clustering analysis is executed to generate the clusters which represent the multi-states of the degradation process. The failure state cluster is extracted, and then the distance between the pre-processed data and the cluster is calculated. Therefore, one-dimensional time series are generated and defined as the health indices. Afterwards the degradation models are built based on the health indices. Finally, the RUL of a testing unit can be estimated by similarity analysis with the models. Hierarchical clustering (HC) and relevance vector machine (RVM) are the main algorithms employed in this paper. To validate the proposition, a case study is performed on turbofan engines data from Prognostics Center of Excellence (PCoE) at NASA Ames Research Center, and sufficient comparisons were given.
Silniki turbowentylatorowe niepoddane konserwacji ulegają stopniowej degradacji aż do czasu wystąpienia uszkodzenia lub zakończenia cyklu życia. Rzetelna ocena degradacji oraz pozostałego okresu użytkowania (RUL) mają wpływ zarówno na bezpieczeństwo maszyn lotniczych jak i racjonalne podejmowanie decyzji dotyczących utrzymania ruchu. W artykule zaproponowano sterowaną danymi metodę prognostyczną opartą na danych o pracy do czasu uszkodzenia (run-to failure, RTF), które są wielowymiarowymi danymi sensorycznymi zbieranymi podczas normalnej pracy silnika aż do jego uszkodzenia. Po niezbędnej wstępnej obróbce danych, przeprowadzono analizę skupień w celu wygenerowania skupień reprezentujących multi-stany procesu degradacji. Wyodrębniono klaster stanów uszkodzenia, a następnie obliczono odległość między wstępnie przetworzonymi danymi a wyodrębnionym klastrem. Następnie wygenerowano jednowymiarowe szeregi czasowe, które zdefiniowano jako wskaźniki stanu technicznego. Na podstawie tych wskaźników zbudowano modele degradacji. Wreszcie, w oparciu o analizę podobieństwa do opracowanych modeli oceniono RUL jednostki testowej. Główne algorytmy zastosowane w niniejszym opracowaniu to algorytmy grupowania hierarchicznego (HC) oraz maszyny wektorów istotnych (RVM). Aby zweryfikować zaproponowaną w pracy metodę, przeprowadzono studium przypadku z wykorzystaniem danych dot. silników turbowentylatorowych pochodzące z Prognostic Center of Excellence (PCoE) przy NASA Ames Research Center oraz przedstawiono odpowiednie porównania.
Źródło:
Eksploatacja i Niezawodność; 2016, 18, 4; 621-631
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and Properties of RDX-Nitrocellulose Microspheres
Autorzy:
Shi, X.
Wang, J
Li, X.
Powiązania:
https://bibliotekanauki.pl/articles/358363.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
RDX
nitrocellulose
flash vaporization process
thermal stability
Opis:
A new insensitive explosive based on RDX and with Nitrocellulose (NC) as binder has been prepared using a flash vaporization process. Scanning electron microscopy was used to characterize the morphology and particle size of the resulting RDX-NC microspheres. X-ray photoelectron spectroscopy, Differential Scanning Calorimetry, impact sensitivity, vacuum stability and burning rate of raw RDX, RDX-NC and RDX-1 were also used to characterize the explosive. The RDX-NC microspheres were found to have a fibrous surface. The microspheres ranged in size from 0.5 μm to 4 μm. The NC formed a coat on the surface of the RDX. The activation energies of raw RDX, RDX-1 and RDX-NC were found to be 200.8 kJ·mol−1, 183.9 kJ·mol−1 and 187.2 kJ·mol−1, respectively. The drop heights of raw RDX, RDX-1 and RDX-NC were found to be 21.3 cm, 51.7 cm and 82.9 cm, respectively. The friction sensitivity of RDX-NC was lower than that of raw RDX and RDX-1. In the vacuum stability test, the volumes of evolved gas from raw RDX, RDX-1 and RDX-NC were 0.12 mL·g−1, 0.12 mL·g−1, and 0.09 mL·g−1, respectively. The burning rates of RDX-NC-based propellants were higher than that of RDX-1 and raw RDX based propellants at 5-15 MPa. The burning rate pressure exponent of RDX-NC based propellants is 0.9929 at 40-200 MPa.
Źródło:
Central European Journal of Energetic Materials; 2016, 13, 4; 871-881
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of float-sink and progressive release flotation of ground products of coal middlings
Autorzy:
Xie, W.
He, Y.
Luo, C.
Zhang, X.
Li, H.
Yu, J.
Wang, H.
Shi, F.
Powiązania:
https://bibliotekanauki.pl/articles/109500.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
coal middlings
float-sink
progressive release flotation
XPS
EDX
Opis:
An additional recovery of coking coal middlings can be utilized for increasing of the concentrate yield of coking coal. A combined flow sheet of comminution and flotation can realize this target. To investigate the effect of grinding process on further flotation of ground products, progressive release flotation tests were used to compare with the float-sink tests, which were regarded as a criterion. Coal middlings were ground by wet-milling with iron balls to <0.5 mm. Curves of ash vs. cumulative yields of sized products indicated that the concentrate yield of coal separated by progressive release flotation was lower than that of coal benefited by the float-sink test, with the same ash for four size fractions (0.5-0.25 mm, 0.25-0.125 mm, 0.125-0.074 mm and <0.074 mm). Distributions of elements conducted by energy disperse spectroscopy (EDX) showed that associated kaolinite was liberated and exposed on the surface. It led to the shift of local surface property from hydrophobicity to hydrophilicity. Meanwhile, analyses of chemical property performed by an X-Ray photoelectron spectrometer (XPS) depicted that the hydrophilic mineral FeOOH, which generated in the grinding process, was adsorbed on the coal surface. Flotation of the ground products were worsened due to the increase of hydrophilicity of the coal surface.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 2; 675-684
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Jurassic ammonites of the Wulong area, Tingri County, Tibet
Autorzy:
Morton, N.
Meister, Ch.
Ruellau, L.
Shi, X.
Powiązania:
https://bibliotekanauki.pl/articles/2061072.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
ammonites
Jurassic
Tibet
systematics
biostratigraphy
amonity
jura
Tybet
systematyka
biostratygrafia
Opis:
The Jurassic succession west of Wulong village, Tingri County, southern Tibet, is described. Lithostratigraphical classification uses pre-existing terminology for formations, and an informal subdivision into members is proposed. An important structural dislocation, in the form of a small-scale flower structure, affects the Zhamure Formation straddling the Triassic/Jurassic boundary but does not affect the underlying Derirong Formation (Rhaetian) or the overlying Wulong Formation (Lower Jurassic). No other major structural discontinuities could be recognised. New finds of ammonites in situ include a new genus and species of possible schlotheimiid, Womalongiceras inflatum, with a probable age of Sinemurian or slightly younger. Two separate beds yielded rich assemblages of crushed ammonites identified as Nyalamoceras nyalamensis Chao and Wang (1956) here interpreted as a hammatoceratid. The age of these is reinterpreted as uppermost Aalenian on the basis of an accompanying specimen of ?Pseudolioceras (Tugurites) sp. nov. and poorly preserved ammonites from higher beds identified as graphoceratids (?Graphoceras).
Źródło:
Volumina Jurassica; 2015, 13, 2; 1--21
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nano-silica reinforced hybrid light-diffusing films with enhanced mechanical and thermal properties
Autorzy:
Sun, X
Li, N.
Hang, J
Jin, L.
Shi, L
Cheng, Z.
Shang, D
Powiązania:
https://bibliotekanauki.pl/articles/175043.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical materials and properties
nanocomposites
light-diffusing films
sol-gel preparation
nanoparticles
Opis:
Ultraviolet-curable hybrid light-diffusing films with good optical, mechanical and thermal properties were prepared by involving vinyl-silane-modified nano-silica into light-diffusing films. The light-diffusing films were two-phase materials consisting of UV-curable matrix and light-diffusing agent. The effect of three different light-diffusing agents, viz. inorganic layered particle (CaCO3), spherical acrylic resin (MR-7HG) and organosilicone resin (KMP-590) and their contents, on the optical properties of light-diffusing films was studied. The results showed the light-diffusing film exhibited good optical properties (the transmittance was 90.7% and the haze was 95.5%) when KMP-590 was a light-diffusing agent and its content was 25%. It was because that KMP-590 showed good transparency, good dispersion in the UV-curable matrix and the greater difference in refractive index with UV-curable matrix and polycarbonate substrate. Furthermore, the effect of nano-silica on the optical, mechanical and thermal properties of the hybrid light-diffusing films was investigated. Compared to that of the light-diffusing films without nano-silica, the haze of the hybrid light-diffusing films containing nano-silica was lightly enhanced to above 98%, while their transmittance basically remained unchanged at a high value (above 89%). Additionally, scratch and abrasion resistance of the hybrid films were obviously improved by nano-silica especially with the particle size of 10–15 nm. Furthermore, the mechanical property and thermal stability of the hybrid films were improved as the content of nano-silica with the particle size of 10–15 nm increased. The enhanced mechanical property and thermal stability of the films could be attributed to the dense structure induced by the increase in network density with the addition of vinyl-silane-modified nano-silica.
Źródło:
Optica Applicata; 2015, 45, 3; 393-404
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Process Optimization and Characterization of an HMX/Viton Nanocomposite
Autorzy:
Shi, X.
Wang, C.
Wang, J.
Li, X.
An, C.
Ji, W.
Powiązania:
https://bibliotekanauki.pl/articles/358667.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
HMX
spray drying
processing parameters
optimization
impact sensitivity
nanoparticles
Opis:
HMX/Viton A nanocomposites were prepared by a spray drying process using different processing parameters, which included the dry gas inlet temperature, the air flow rate, and the solution feed flow rate. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the nanocomposites. The effects of the processing parameters on the morphology of the samples were investigated and are discussed. The thermal decomposition behaviour and impact sensitivity of the raw HMX and HMX/Viton A nanocomposites were also measured and compared. Optimal morphology and dispersion of the coated samples was achieved when the dry gas inlet temperature and the air and solution feed flow rates were 55 °C, 660 L/h and 1.5 mL/min, respectively. Under these optimal processing conditions, the nanocomposites were spherical in shape, ranged from 0.2-2 μm in size, and were composed of many tiny particles of 50-100 nm in size. The crystal phase of the nanocomposites was the same as that of raw HMX. Compared with those of raw HMX, the melting point and impact sensitivity of the nanocomposites were lower and the thermal decomposition rate was slightly higher.
Źródło:
Central European Journal of Energetic Materials; 2015, 12, 3; 487-495
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Soft Sensing Method Of LS-SVM Using Temperature Time Series For Gas Flow Measurements
Autorzy:
Xu, W.
Fan, Z.
Cai, M.
Shi, Y.
Tong, X.
Sun, J.
Powiązania:
https://bibliotekanauki.pl/articles/221824.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gas flow
soft sensor
support vector machine (SVM)
temperature time series
Opis:
This paper proposes a soft sensing method of least squares support vector machine (LS-SVM) using temperature time series for gas flow measurements. A heater unit has been installed on the external wall of a pipeline to generate heat pulses. Dynamic temperature signals have been collected upstream of the heater unit. The temperature time series are the main secondary variables of soft sensing technique for estimating the flow rate. A LS-SVM model is proposed to construct a non-linear relation between the flow rate and temperature time series. To select its inputs, parameters of the measurement system are divided into three categories: blind, invalid and secondary variables. Then the kernel function parameters are optimized to improve estimation accuracy. The experiments have been conducted both in the single-pulse and multiple-pulse heating modes. The results show that estimations are acceptable.
Źródło:
Metrology and Measurement Systems; 2015, 22, 3; 383-392
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and Characterization of HMX/Estane Nanocomposites
Autorzy:
Shi, X.
Wang, J.
Li, X.
An, Ch.
Powiązania:
https://bibliotekanauki.pl/articles/358274.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
HMX
Estane 5703
spray drying
nanocomposites
thermal stability
Opis:
A new insensitive explosive based on octahydro-1,3,5,7-tetranitro1,3,5,7-tetrazocine (HMX) was prepared by spray drying using Estane 5703 as a binder. Scanning electron microscopy was used to characterize the morphology and particle size of the HMX/Estane 5703 nanocomposites. The composites were analyzed by X-ray diffractometry and differential scanning calorimetry and their impact sensitivity was determined. For comparison, raw HMX was also tested using these three methods. The nanocomposite morphology was found to be microspherical (1 to 8 μm diameter) and composed of many tiny particles, 30 to 150 nm in size. The crystal type of the HMX/Estane 5703 nanocomposites was unchanged. The activation energy, self-ignition temperature and average drop height of the raw HMX were 515.66 kJ·mol-1, 278.63 °C and 18.4 cm, respectively. In comparison, the corresponding values for the HMX/Estane 5703 nanocomposites were 488.92 kJ·mol-1, 279.3 °C and 75.4 cm, respectively.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 3; 433-442
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Simulation of Dynamic Pressure and Displacement for the Top Part of Men’s Socks Using the Finite Element Method
Numeryczna symulacja ciśnienia dynamicznego i przesunięć w górnej części skarpet męskich
Autorzy:
Dan, R.
Dan, M. H.
Fan, X. R.
Chen, D. S.
Shi, Z.
Zhang, M.
Xu, L. B.
Powiązania:
https://bibliotekanauki.pl/articles/234002.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
top part of socks
pressure
displacement
finite element
dynamic
górna część skarpetki
ciśnienie
przemieszczenie
elementy skończone
dynamika
Opis:
Numerical simulation of elastic human body deformation and dynamic pressure and displacement distribution are critical for pressure comfort and optimal design of apparel products. This paper demonstrates an analytical method for simulating dynamic pressure and displacement at the top part of men’s socks using the finite element method (FEM). The dynamic pressure is divided into two parts: the first is pressure with time, and the second is pressure with walking. Pressure with time is set at six periods (maximum 12 h). After measuring pressure values in different periods of time and simulating pressure and displacement distribution using ANSYS software, the tendency of pressure and displacement changes with time at the top part of men’s socks can be obtained. We divided the walking process into four phases to analyse the variation rule of pressure and displacement changes with movement in this research work. Meanwhile the lower leg cross section is divided into four equal regions according to the angle, and dynamic changes in the area shrinkage mass of each region can be calculated, respectively. All these solutions provide a theoretical reference for the optimal design of the top part of men’s socks.
Numeryczna symulacja elastycznej deformacji ciała ludzkiego, dynamicznego ciśnienia i rozkładu przesunięć są krytycznymi czynnikami komfortu i optymalnych rozwiązań ciśnieniowych wyrobów odzieżowych. Przedstawiono analityczną metodę symulacji ciśnień dynamicznych i przesunięć w górnej części męskich skarpet stosując metodę elementów skończonych. Analizę ciśnień dynamicznych przeprowadzono rozpatrując dwa stadia: zmiany ciśnienia w czasie i zmiany przy ruchu związane z chodzeniem. Na podstawie pomiarów ciśnienia i odkształcenia w określonych przedziałach czasowych określono rozkład odkształceń stosując program ANSYS. Proces chodzenia podzielono na cztery fazy. Wszystkie przeprowadzone badania i rozwiązania dostarczyły informacji dla przedstawienia optymalnego sposobu projektowania męskich skarpet.
Źródło:
Fibres & Textiles in Eastern Europe; 2013, 4 (100); 112-117
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 22

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