Elucidating the flow features around piles in local scouring processes is crucial for studies of local scouring mechanisms and scour depth estimates.This study details the flow turbulence characteristics of two submer...Elucidating the flow features around piles in local scouring processes is crucial for studies of local scouring mechanisms and scour depth estimates.This study details the flow turbulence characteristics of two submerged piles that are determined by solving the Navier-Stokes equations with the improved delayed detached eddy simulation model.This model is verified by comparing experimental and numerical results for hydrodynamic parameters with the literature for both square-crossing piles(SCPs)and circular-crossing piles(CCPs).Original topographies of flat and scoured beds(i.e.,the initial and equilibrium scouring stages)are based on experimental results obtained by the authors in the present paper.SCP and CCP flow features in the scouring process are discussed.The results indicate that during the scouring process,the time-averaged drag coefficient and root mean square(rms)of the lift coefficient increase linearly in the CCP test,while the rms of the lift coefficient in the SCP test decreases linearly.Moreover,the minimum pressure coefficient is always located in the upstream corners in the SCP case but moves from 72.5°to 79.5°when the scour hole is completely developed in the CCP case.Downward flow behind the pile,which is generated by separated boundary layers above the top face of the pile,can reach the sand bed and turn the separated shear layers into patches of small vortices in the near-wake regions.Thus,the high shear stress zones are mainly at the scour edges under scoured-bed conditions.展开更多
This work investigates the influence of the type sludge on drainage, plant development, purification performances and biosolids quality. Drainage properties were measured through the frequency of clogging, the percent...This work investigates the influence of the type sludge on drainage, plant development, purification performances and biosolids quality. Drainage properties were measured through the frequency of clogging, the percentage of leachate recovered and the dryness of accumulated sludge. Plant development was measured through the density, the height and the stem diameter. Purification performance was evaluated from the reduction rate. Biosolids quality was measured after 3 months of maturation. The results show that the clogging frequencies were 9.5%;0% and 3.7%;the volume of leachate recovered was 42.2%;20.4% and 24.7% and, the dryness was 33.4%;61.1% and 52.4% for FS-ST, FS-STT and SS respectively. Plants densities were about, with densities 197.1, 171.3 and 178.3 plants/m2 in beds fed respectively with FS-ST, FS-STT and SS. Despite the high removal rates, the concentrations of pollutants in the leachates are above the Senegalese standard NS 05-061 for discharge into the environment. The biosolids are all mature with C/N and NH4+/NO3?ratios lower than 12 and 1 respectively. The biosolids are also rich in organic and mineral elements. The concentrations of Ascaris eggs are higher than the WHO recommendations. These biosolids should be stored for additional time or composted.展开更多
As a high-performance material with great application potential,the application of carbon nanotubes has been limited by their production volume.A distributor-less conical fluidized bed is the main equipment used in th...As a high-performance material with great application potential,the application of carbon nanotubes has been limited by their production volume.A distributor-less conical fluidized bed is the main equipment used in the industrial production of carbon nanotubes.To improve the production volume and product quality of carbon nanotubes,the study of fluidized-bed-diameter scaling is important.Three different diameters of distributor-less conical fluidized beds were established,and then the particle behavior and bubble characteristics of carbon nanotube clusters at these bed diameters were investigated.Time-series and wavelet analysis methods were used to analyze the pressure-fluctuation signals inside the fluidized beds.Results showed that the distributor-less design caused the airflow to break through the middle of the bed,which did not change with the change in bed diameter.The powder-bridging phenomenon of carbon nanotube clusters in a 100-mm-diameter fluidized bed was related to the special microstructure of carbon nanotube clusters.The frequency of pressure fluctuations in the bed decreased nonlinearly with increasing bed diameter.This study can guide the design and scale-up of distributor-less conical fluidized beds,especially for the scale-up of carbon nanotube production equipment,which can contribute to the improvement of carbon nanotubes’capacity and quality in industrial production.展开更多
Over the past two decades,it has become increasingly apparent that early Mars may once have been warmer,wetter and more habitable for microbial life than it is today,which has spurred discussions about potential biosi...Over the past two decades,it has become increasingly apparent that early Mars may once have been warmer,wetter and more habitable for microbial life than it is today,which has spurred discussions about potential biosignatures that may be preserved in Martian sediments.An impediment to this line of research is the pervasive oxidation of Mars’surface due to photochemical oxidants that have likely destroyed remnants of organic matter.Here,we investigate whether nitrogen(N)transferred from biomass to phyllosilicate minerals during diagenesis can be preserved in oxidized mudrocks.We investigate two sequences of terrestrial Proterozoic red beds,namely the Sibley Group(1.4 Ga)in Canada and the Stoer Group(1.2 Ga)in Scotland,and we find enrichments in authigenic N in the range of several tens of ppm in both units.The highest concentrations(ca.100 ppm on average)are found in the most desiccated red beds of the Stoer Group,concurrent with enrichments in potassium(K).We discuss similarities and differences between the two sets of rocks with regards to salinity,pH,biological productivity and K-metasomatism,and we conclude that the ideal mechanism for the preservation of biogenic N in red beds may be in-situ release of ammonium from microbial mats into the clay substrate,possibly facilitated by early diagenetic,biologically induced illitization.Illite and smectite have been observed on Mars,and experiments suggest that Martian waters contained moderate amounts of dissolved K.Hence,it is conceivable that a similar K and N enrichment process could have occurred as to what we document for the Proterozoic,preserving evidence of life that may have survived to the modern day.展开更多
Methods and procedures of three-dimensional (3D) characterization of the pore structure features in the packed ore particle bed are focused. X-ray computed tomography was applied to deriving the cross-sectional imag...Methods and procedures of three-dimensional (3D) characterization of the pore structure features in the packed ore particle bed are focused. X-ray computed tomography was applied to deriving the cross-sectional images of specimens with single particle size of 1-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-9, 9-10 ram. Based on the in-house developed 3D image analysis programs using Matlab, the volume porosity, pore size distribution and degree of connectivity were calculated and analyzed in detail. The results indicate that the volume porosity, the mean diameter of pores and the effective pore size (d50) increase with the increasing of particle size. Lognormal distribution or Gauss distribution is mostly suitable to model the pore size distribution. The degree of connectivity investigated on the basis of cluster-labeling algorithm also increases with increasing the particle size approximately.展开更多
A Markov chain-based stochastic model (MCM) is developed to simulate the movement of particles in a 2D bubbling fluidized bed (BFB). The state spaces are determined by the discretized physical cells of the bed, an...A Markov chain-based stochastic model (MCM) is developed to simulate the movement of particles in a 2D bubbling fluidized bed (BFB). The state spaces are determined by the discretized physical cells of the bed, and the transition probability matrix is directly calculated by the results of a discrete element method (DEM) simulation. The Markov property of the BFB is discussed by the comparison results calculated from both static and dynamic transition probability matrices. The static matrix is calculated based on the Markov chain while the dynamic matrix is calculated based on the memory property of the particle movement. Results show that the difference in the trends of particle movement between the static and dynamic matrix calculation is very small. Besides, the particle mixing curves of the MCM and DEM have the same trend and similar numerical values, and the details show the time averaged characteristic of the MCM and also expose its shortcoming in describing the instantaneous particle dynamics in the BFB.展开更多
Lacustrine deposits exposed at Daohugou, Inner Mongolia, China, have yielded superbly preserved vertebrate fossils. The fossil beds were first misinterpreted as of Early Cretaceous age, based on alleged occurrences of...Lacustrine deposits exposed at Daohugou, Inner Mongolia, China, have yielded superbly preserved vertebrate fossils. The fossil beds were first misinterpreted as of Early Cretaceous age, based on alleged occurrences of key fossils of the Jehol Biota. Compelling evidence revealed by more rigorous research involving regional biostratigraphy, radiometric dating, and paleontology supports the Middle Jurassic age of the fossil beds. Despite the awesome evidence for the Middle Jurassic age of the Daohugou beds, the age dispute has been resurrected recently by invoking an overturned stratigraphic sequence. A careful review of the data, however, found no evidence that this sequence has been overturned. In addition, many of the assumptions, on which the conjecture of the fossil beds being post- Middle Jurassic is imprudently based, are self-contradictory or otherwise misleading. Thus, the post- Middle Jurassic age of the Daohugou beds as an unfounded conclusion can readily be dismissed.展开更多
To identify a strategy for earlier sowing and harvesting of spring maize(Zea mays L.) in an alternative maize–maize double cropping system, a 2-year field experiment was performed at Quzhou experimental station of Ch...To identify a strategy for earlier sowing and harvesting of spring maize(Zea mays L.) in an alternative maize–maize double cropping system, a 2-year field experiment was performed at Quzhou experimental station of China Agricultural University in 2014 and 2015. A short-season cultivar, Demeiya number 1(KX7349), was used in the experiment. Soil temperature to 5 cm depth in the early crop growth stage, crop growth, crop yield, and water use of different treatments(plastic film-mulched raised bed(RF) and flat field without plastic film mulching(CK) in 2014; RF, plastic film-mulched flat field(FF), and CK in 2015)were measured or calculated and compared. Soil temperature in the film-mulched treatments was consistently higher than that in CK(1.6–3.5 °C in average) during the early growth stage. Crops in plastic film-mulched treatments used 214 fewer growing-degree days(GDDs) in 2014 and 262 fewer GDDs in 2015. In 2014, the RF treatment yielded 32.7%higher biomass than CK, although its 9.4% higher grain yield was not statistically significant. Also, RF used 17.9% less water and showed 33.1% higher water use efficiency(WUE) than CK. In 2015, RF and FF showed 56.2% and 49.5% higher yield, 15.0% and 4.5%lower water use(ET), and 63.4% and 75.7% higher WUE, respectively, than CK. RF markedly increased soil temperature in the early crop season, accelerated crop growth, reduced ET,and greatly increased crop yield and WUE. Compared with FF, RF had no obvious effect on crop growth rate, although soil temperature during the period between sowing and stem elongation was slightly increased. However, RF resulted in lower ET and higher WUE than FF. Effects of RF on soil water dynamics as well as its cost-effectiveness remain topics for further study.展开更多
The traditional fixed-bed reactor design is usually not suitable for the low tube-to-particle diameter ratios(N = D/d b 8) where the local phenomena of channeling near the wall and backflow in the bed are dominant. Th...The traditional fixed-bed reactor design is usually not suitable for the low tube-to-particle diameter ratios(N = D/d b 8) where the local phenomena of channeling near the wall and backflow in the bed are dominant. The recent"solid particle" meshing method is too complicated for mesh generation, especially for non-spherical particles in large random packed beds, which seriously hinders its development. In this work, a novel high-fidelity mesh model is proposed for simulation of fixed bed reactors by combining the immersed boundary and adaptive meshing methods. This method is suitable for different shapes of particles, which ingeniously avoids handling the complex "contact point" problem. Several packed beds with two different shapes of particles are investigated with this model, and the local flow in the bed is simulated without geometrical simplification. The predicted pressure drop across the fixed bed and heat transfer of the single particle are in good agreement with the corresponding empirical relations. Compared with spherical particles, the packed bed packing with pentaphyllous particles has lower pressure drop and better heat/mass transfer performance, and it shows that this method can be used for the screening of particle shapes in a fixed bed.展开更多
Based on the subdivision into three members of the Lower Cretaceous Jiufotang Formation in western Liaoning, this paper deals mainly with the division and correlation of precious fossil birdand reptile-bearing beds of...Based on the subdivision into three members of the Lower Cretaceous Jiufotang Formation in western Liaoning, this paper deals mainly with the division and correlation of precious fossil birdand reptile-bearing beds of the formation in the Dachengzi, Chaoyang, Dapingfang.Meileyingzi and Fuxin-Yixian basins. Among them, the precious fossil-bearing beds in the Dachengzi Basin may be recognized as the Xidagou Bed of the second member and the Yangcaogoudonggou Bed of the third member; those in the Chaoyang Basin may be confirmed as the Shangheshou Bed of the second member and the Dongpochi Bed of the third member; those in the Dapingfang-Meileyingzi Basin are as the Lamagou Bed of the second member, the Huanghuagou Bed of the lower third member and the Yuanjiawa Bed of the upper third member; and those in the Fuxin-Yixian Basin are listed as the Tuanshanzi Bed of the second member and the Pijiagou Bed of the third member. Since these basins are distinctly separated and the bird and reptile fossils are mostly new genera and species, we have to use the associated fossil ostracod assemblages as index to correlate the Xidagou Bed with the Shangheshou Bed and the Lamagou Bed, and to correlate the Yuanjiawa Bed with the Yangcaogoudonggou Bed and the Pijiagou Bed. Primarily, we established the sequence of the precious fossil-bearing beds of the Jiufotang Formation in western Liaoning. They are represented by, in ascending order, the Xidagou Bed of the second member, the Huanghuagou Bed of the lower third member, and the Yuanjiawa Bed of the upper third member. Obviously, this work has significance for the study on the time-space distribution and radiation of birds and dinosaurs during the period of the middle Early Cretaceous.展开更多
One of the new directions in the field of Cretaceous research is to elucidate the mechanism of the sedimentary transition from the Cretaceous black shales to oceanic red beds. A chemical sequential extraction method w...One of the new directions in the field of Cretaceous research is to elucidate the mechanism of the sedimentary transition from the Cretaceous black shales to oceanic red beds. A chemical sequential extraction method was applied to these two types of rocks from southern Tibet to investigate the burial records of reactive iron. Results indicate that carbonate-associated iron and pyrite are relatively enriched in the black shales, but depleted or absent in red beds. The main feature of the reactive iron in the red beds is relative enrichment of iron oxides (largely hematite), which occurred during syn-depostion or early diagenesis. The ratio between iron oxides and the total iron indicates an oxygen-enriched environment for red bed deposition. A comparison between the reactive iron burial records and proxies of paleo-productivity suggests that paleo-productivity decreases when the ratio between iron oxides and the total iron increases in the red beds. This phenomenon could imply that the relationship between marine redox and productivity might be one of the reasons for the sedimentary transition from Cretaceous black shale to oceanic red bed deposition.展开更多
The planktic foraminifera of the Chuangde Formation (Upper Cretaceous Oceanic Red Beds, CORBs) as exposed at Tianbadong section, Kangmar, southern Tibet has been firstly studied for a detailed for a detailed biostra...The planktic foraminifera of the Chuangde Formation (Upper Cretaceous Oceanic Red Beds, CORBs) as exposed at Tianbadong section, Kangmar, southern Tibet has been firstly studied for a detailed for a detailed biostratigraphy elaboration. A rich and well-preserved planktic foraminifera were recovered from the Chuangde Formation of the Tianbadong section and the Globotruncanita elevata, Globotruncana ventricosa, Radotruncana calcarata, Globotruncanella havanensis, Globotruncana aegyptiaca, Gansserina gansseri and Abathomphalus mayaroensis zones have been recognized. The planktic foraminiferal assemblage points to an early Campanian to Maastrichitian age for the CORBs of the eastern North Tethyan Himalayan sub-belt, which also provides a better understanding of the shifting progress of the Indian Plate to the north and the evolution of the Neotethyan ocean. The lithostratigraphy of the Chuangde Formation of the Tianbadong section comprises two lithological sequences observed in ascending succession: a lower unit (the Shale Member) mainly composed of purple (cherry-red, violet-red) shales with interbedded siltstones and siliceous rocks; and an upper unit (the Limestone Member) of variegated limestones. The strata of the Chuangde Formation in the Tianbadong section are similar to CORBs in other parts of the northern Tethyan Himalaya area of Asia (Gyangze, Sa'gya, Sangdanlin, northern Zanskar, etc.). The fossil contents of the Chuangde Formation in the sections (CORBs) studied provide a means of correlation with the zonation schemes for those of the northern Tethyan Himalayan sub-belt and the Upper Cretaceous of the southern Tethyan Himalayan sub-belt. Paleogeographic reconstruction for the Late Cretaceous indicates that the Upper Cretaceous Chuangde Formation (CORBs) and correlatable strata in northern Zanskar were representative of slope to basinal deposits, which were situated in the northern Tethyan Belt. Correlatable Cretaceous strata in Spiti and Gamba situated in the southern Tethyan Belt in contrast were deposited in shelf environments along the Tethyan Himalayan passive margin. CORBs are most likely formed by the oxidation of Fe(II)-enriched, anoxic deep ocean water near the chemocline that separated the oxic oceanic surface from the anoxic.展开更多
In recent years, great progress has been made constantly in oil and gas exploration in the Lungudong region of the Tarim Basin. However, progress has been slow in the evaluation of its main oil-producing horizons -- t...In recent years, great progress has been made constantly in oil and gas exploration in the Lungudong region of the Tarim Basin. However, progress has been slow in the evaluation of its main oil-producing horizons -- the Ordovician carbonate reservoir beds. Based on previous researches and on the various data such as drilling, geology and oil test, in combination with the interpretation of each single-well imaging and conventional logging data, and through analysis and comparison, the identification methods in imaging and conventional logging for four types of carbonate reservoir beds in this region are summarized in this paper. Calculation formulas for four reservoir bed parameters, i. e. shale content, porosity, permeability and oil saturation in this region are proposed; and reservoir beds in this region are divided into three levels (Ⅰ, Ⅱ and Ⅲ) by combining oil test data and logging data, The lower limits of the effective porosity of reservoir beds and the fracture porosity of effective reservoir beds are determined as 1.8% and 0.04%, respectively. The physical property parameters are calculated by conventional logging curves, and the most advantageous areas for reservoir development are predicted comprehensively. On the plane, the high-value zones of reservoir bed parameters are mainly concentrated in the N-S-trending strike-slip fault, the Sangtamu fault horst zone and near the LG38 well area; vertically, the reservoir bed parameters of the Yijianfang Formation are better than those of the Yingshan and Lianglitage formations.展开更多
LA-ICPMS Zircon U-Pb dating is applied to volcanic rocks overlying and underlying the Salamander-bearing bed in the Daohugou beds of Ningcheng in Inner Mongola and Reshuichang of Lingyuan and Mazhangzi of Jianping in ...LA-ICPMS Zircon U-Pb dating is applied to volcanic rocks overlying and underlying the Salamander-bearing bed in the Daohugou beds of Ningcheng in Inner Mongola and Reshuichang of Lingyuan and Mazhangzi of Jianping in western Liaoning. The results indicate that the youngest age of the rocks in Daohugou of Ningcheng is 158 Ma, and the oldest one is 164 Ma. Synthesized researches indicate that the salamander-bearing beds in Daohugou of Ningcheng, Reshuichang of Lingyuan and Mazhangzi of Jianping were developed in the same period. The Daohugou beds were formed in the geological age of 164-158 Ma of the middle-late Jurassic. Whilst, the Daohugou beds and its corrdative strata should correspond to the Tiaojishan Formation (or Lanqi Formation) of the middle Jurassic in northern Hebei Province and western Liaoning Province, based on the disconformity between the Daohugou beds and its overlaying beds of the Tuchengzi Formation of Late Jurassic and the Jehol Beds of early Cretaceous, and the disconformity between the Daohugou Beds and its underlying Jiulongshan Formation, which is composed of conglomerate, sandstone, shale with coal and thin coal beds.展开更多
Cretaceous oceanic red beds (CORBs) represented by red shales and marls, were deposited during the Cretaceous and early Paleocene, predominantly in the Tethyan realm, in lower slope and abyssal basin environments. D...Cretaceous oceanic red beds (CORBs) represented by red shales and marls, were deposited during the Cretaceous and early Paleocene, predominantly in the Tethyan realm, in lower slope and abyssal basin environments. Detailed studies of CORBs are rare; therefore, we compiled CORBs data from deep sea ocean drilling cores and outcrops of Cretaceous rocks subaerially exposed in southern Europe, northwestern Germany, Asia and New Zealand. In the Tethyan realm, CORBs mainly consist of reddish or pink shales, limestones and marlstones. By contrast, marlstones and chalks are rare in deep-ocean drilling cores. Upper Cretaceous marine sediments in cores from the Atlantic Ocean are predominantly various shades of brown, reddish brown, yellowish brown and pale brown in color. A few red, pink, yellow and orange Cretaceous sediments are also present. The commonest age of CORBs is early Campanian to Maastrichtian, with the onset mostly of oxic deposition often after Oceanic Anoxic Events (OAEs), during the early Aptian, late Albian-early Turonian and Campanian. This suggests an indicated and previously not recognized relationship between OAEs, black shales deposition and CORBs. CORBs even though globally distributed, are most common in the North Atlantic and Tethyan realms, in low to mid latitudes of the northern hemisphere; in the South Atlantic and Indian Ocean in the mid to high latitudes of the southern hemisphere; and are less frequent in the central Pacific Ocean. Their widespread occurrence during the late Cretaceous might have been the result of establishing a connection for deep oceanic current circulation between the Pacific and the evolving connection between South and North Atlantic and changes in oceanic basins ventilation.展开更多
The no-till seeders of various soil opener configurations have been shown to produce various soil physical responses in relation to soil and climate conditions, thus affecting crop performance in permanent raised beds...The no-till seeders of various soil opener configurations have been shown to produce various soil physical responses in relation to soil and climate conditions, thus affecting crop performance in permanent raised beds (PRB) systems. This is particularly important in arid Northwest China where large volumes of residue are retained on the soil surface after harvest. In Zhangye, Gansu Province, China, a field trial assessed the effects of three typical (powered-chopper, powered-cutter and powered-disc) PRB no-till seeders and one traditional seeder on soil disturbance, residue cover index, bulk density, fuel consumption, plant growth, and subsequent yield. In general, seedbed conditions and crop performance for PRB no- till seeders seeded plots were better than for traditional seeded plots. In PRB cropping system, the powered-chopper seeder decreased mean soil disturbance and increased residue cover index compared to powered-disc and -cutter seeders. However, the results indicated that soil bulk density was 2.3-4.8% higher, soil temperature was 0.2-0.6℃ lower, and spring wheat emergence was 3.2-4.7% less. This was attributed to greater levels of residue cover and firmer seedbeds. Spring maize and wheat performance in the powered-cutter and -disc treatments was better (non-significant) than powered- chopper treatment. So powered disc no-till seeder, which generally provided the best planting condition and the highest yield, appeared to be the suitable seeder in heavy residue cover conditions. Considering the precision requirements for soil disturbance and residue cover, the powered strip-chopping no-till seeder could be a suitable option for PRB cropping system in Northwest China. Although these results are preliminary, they are still valuable for the design and selection of no-till seeders for PRB cropping systems in arid Northwest China.展开更多
Red beds cover approximately 9.5%of China,and are home to approximately 144 million people.In total,83%of these lands are distributed in humid regions making it an important part of research on red bed soil erosion in...Red beds cover approximately 9.5%of China,and are home to approximately 144 million people.In total,83%of these lands are distributed in humid regions making it an important part of research on red bed soil erosion in China in these areas.This paper presents the main types of land degradation in red bed landscapes and the status of current soil erosion in a typical red bed basin,the Nanxiong Basin located in the north of Guangdong Province,China,and establishes the connection between management strategies and regional economic development in humid red bed regions of China.The soil erosive modulus was calculated in the Nanxiong Basin by using RUSLE(The Revised Universal Soil Loss Equation).The results of overlapping analyses demonstrated that appropriate measures,such as the Return Farmland to Forests initiative,should be taken at the junction of central red bed areas and mountainous areas in order to mitigate current soil erosion.Two examples are presented to demonstrate this:the tourism development in Mt.Danxiashan,a noted scenic mountainous area near Nanxiong Basin,and the land degradation mitigation in the Nanxiong Basin.Both examples promote local economic growth while simultaneously protecting the environment.A‘stakeholder'strategy is pursued at Mt.Danxiashan,which can help residents to understand their positive effects on the environment as well as increase their income.The second example,in Nanxiong City,showcases how local farmers became stakeholders by implementing contract responsibility and self-support systems for economic forests and terraced land in the 1980s.展开更多
A heat pump assisted fluidized bed grain drying experimental system wasdeveloped. Based on this system, a serial of experiments was performed under four kinds of air cycleconditions. According to the experimental anal...A heat pump assisted fluidized bed grain drying experimental system wasdeveloped. Based on this system, a serial of experiments was performed under four kinds of air cycleconditions. According to the experimental analysis, an appropriate drying medium-air cycle for theheat pump assisted fluidized bed drying equipment was decided, which is different from the commonlyused heat pump assisted drying system. The experimental results concerning the drying operationperformance of the new system show that the averaged coefficient of performance (COP) can reach morethan 2.5. The economical evaluation was performed and the power consumption for removing a kilogramwater from grains was about 0.485 kW-h/kg (H_2O), which shows its reasonable commercial efficiencyand great application potentiality in future market.展开更多
Torpedo anchors have been used in mooring systems for deep-water oil and gas projects owing to their prominent advantages, such as low cost and easy installation. The maximum force of torpedo anchors is crucial not on...Torpedo anchors have been used in mooring systems for deep-water oil and gas projects owing to their prominent advantages, such as low cost and easy installation. The maximum force of torpedo anchors is crucial not only to the safety and stability of vessels and other marine facilities, but also for an economical design. It is necessary to develop reliable formula for fast predicting their maximum inclined force of a torpedo anchor in cohesive beds. In this study, the maximum inclined force of a torpedo anchor vertically embedded in cohesive beds was extensively investigated. 316 sets of inclined pullout laboratory tests were carried out for 9 differently shaped torpedo anchors which were vertically embedded in different cohesive beds. The loading curves were automatically acquisitioned and their characteristics were analyzed. The load angle relative to the horizontal varied from 20° to 90°. A new formula for fast calculating the maximum inclined force of the torpedo anchor vertically embedded in cohesive beds was obtained based on force analysis and a nonlinear regression on the data from the present and other studies. Effect aspects on the tests are discussed and further studies are highlighted.展开更多
基金support from the National Natural Science Foundation of China (Nos.52301324 and 52001276)the Natural Science Foundation of Zhejiang Province (No.LQ24E090001)+2 种基金the Open Fund of Key Laboratory of Estuary and Coast of Zhejiang Province (No.ZIHE21005)the Natural Science Foundation of Ningbo (No.2021J096)the Zhejiang Transportation Science and Technology (No.2021064)。
文摘Elucidating the flow features around piles in local scouring processes is crucial for studies of local scouring mechanisms and scour depth estimates.This study details the flow turbulence characteristics of two submerged piles that are determined by solving the Navier-Stokes equations with the improved delayed detached eddy simulation model.This model is verified by comparing experimental and numerical results for hydrodynamic parameters with the literature for both square-crossing piles(SCPs)and circular-crossing piles(CCPs).Original topographies of flat and scoured beds(i.e.,the initial and equilibrium scouring stages)are based on experimental results obtained by the authors in the present paper.SCP and CCP flow features in the scouring process are discussed.The results indicate that during the scouring process,the time-averaged drag coefficient and root mean square(rms)of the lift coefficient increase linearly in the CCP test,while the rms of the lift coefficient in the SCP test decreases linearly.Moreover,the minimum pressure coefficient is always located in the upstream corners in the SCP case but moves from 72.5°to 79.5°when the scour hole is completely developed in the CCP case.Downward flow behind the pile,which is generated by separated boundary layers above the top face of the pile,can reach the sand bed and turn the separated shear layers into patches of small vortices in the near-wake regions.Thus,the high shear stress zones are mainly at the scour edges under scoured-bed conditions.
文摘This work investigates the influence of the type sludge on drainage, plant development, purification performances and biosolids quality. Drainage properties were measured through the frequency of clogging, the percentage of leachate recovered and the dryness of accumulated sludge. Plant development was measured through the density, the height and the stem diameter. Purification performance was evaluated from the reduction rate. Biosolids quality was measured after 3 months of maturation. The results show that the clogging frequencies were 9.5%;0% and 3.7%;the volume of leachate recovered was 42.2%;20.4% and 24.7% and, the dryness was 33.4%;61.1% and 52.4% for FS-ST, FS-STT and SS respectively. Plants densities were about, with densities 197.1, 171.3 and 178.3 plants/m2 in beds fed respectively with FS-ST, FS-STT and SS. Despite the high removal rates, the concentrations of pollutants in the leachates are above the Senegalese standard NS 05-061 for discharge into the environment. The biosolids are all mature with C/N and NH4+/NO3?ratios lower than 12 and 1 respectively. The biosolids are also rich in organic and mineral elements. The concentrations of Ascaris eggs are higher than the WHO recommendations. These biosolids should be stored for additional time or composted.
基金supported by the National Natural Science Foundation of China(52336003,52206096,52176076)the Special Expert Project of Shandong Province Taishan Scholars Program(ts20190937).
文摘As a high-performance material with great application potential,the application of carbon nanotubes has been limited by their production volume.A distributor-less conical fluidized bed is the main equipment used in the industrial production of carbon nanotubes.To improve the production volume and product quality of carbon nanotubes,the study of fluidized-bed-diameter scaling is important.Three different diameters of distributor-less conical fluidized beds were established,and then the particle behavior and bubble characteristics of carbon nanotube clusters at these bed diameters were investigated.Time-series and wavelet analysis methods were used to analyze the pressure-fluctuation signals inside the fluidized beds.Results showed that the distributor-less design caused the airflow to break through the middle of the bed,which did not change with the change in bed diameter.The powder-bridging phenomenon of carbon nanotube clusters in a 100-mm-diameter fluidized bed was related to the special microstructure of carbon nanotube clusters.The frequency of pressure fluctuations in the bed decreased nonlinearly with increasing bed diameter.This study can guide the design and scale-up of distributor-less conical fluidized beds,especially for the scale-up of carbon nanotube production equipment,which can contribute to the improvement of carbon nanotubes’capacity and quality in industrial production.
基金EES acknowledges funding from a NERC Frontiers grant(NE/V010824/1)Leverhulme Trust research grant(RPG-2022-313).
文摘Over the past two decades,it has become increasingly apparent that early Mars may once have been warmer,wetter and more habitable for microbial life than it is today,which has spurred discussions about potential biosignatures that may be preserved in Martian sediments.An impediment to this line of research is the pervasive oxidation of Mars’surface due to photochemical oxidants that have likely destroyed remnants of organic matter.Here,we investigate whether nitrogen(N)transferred from biomass to phyllosilicate minerals during diagenesis can be preserved in oxidized mudrocks.We investigate two sequences of terrestrial Proterozoic red beds,namely the Sibley Group(1.4 Ga)in Canada and the Stoer Group(1.2 Ga)in Scotland,and we find enrichments in authigenic N in the range of several tens of ppm in both units.The highest concentrations(ca.100 ppm on average)are found in the most desiccated red beds of the Stoer Group,concurrent with enrichments in potassium(K).We discuss similarities and differences between the two sets of rocks with regards to salinity,pH,biological productivity and K-metasomatism,and we conclude that the ideal mechanism for the preservation of biogenic N in red beds may be in-situ release of ammonium from microbial mats into the clay substrate,possibly facilitated by early diagenetic,biologically induced illitization.Illite and smectite have been observed on Mars,and experiments suggest that Martian waters contained moderate amounts of dissolved K.Hence,it is conceivable that a similar K and N enrichment process could have occurred as to what we document for the Proterozoic,preserving evidence of life that may have survived to the modern day.
基金Projects(50934002,51074013,51304076,51104100)supported by the National Natural Science Foundation of ChinaProject(IRT0950)supported by the Program for Changjiang Scholars Innovative Research Team in Universities,ChinaProject(2012M510007)supported by China Postdoctoral Science Foundation
文摘Methods and procedures of three-dimensional (3D) characterization of the pore structure features in the packed ore particle bed are focused. X-ray computed tomography was applied to deriving the cross-sectional images of specimens with single particle size of 1-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-9, 9-10 ram. Based on the in-house developed 3D image analysis programs using Matlab, the volume porosity, pore size distribution and degree of connectivity were calculated and analyzed in detail. The results indicate that the volume porosity, the mean diameter of pores and the effective pore size (d50) increase with the increasing of particle size. Lognormal distribution or Gauss distribution is mostly suitable to model the pore size distribution. The degree of connectivity investigated on the basis of cluster-labeling algorithm also increases with increasing the particle size approximately.
基金The National Science Foundation of China(No.51276036,51306035)the Fundamental Research Funds for the Central Universities(No.KYLX_0114)
文摘A Markov chain-based stochastic model (MCM) is developed to simulate the movement of particles in a 2D bubbling fluidized bed (BFB). The state spaces are determined by the discretized physical cells of the bed, and the transition probability matrix is directly calculated by the results of a discrete element method (DEM) simulation. The Markov property of the BFB is discussed by the comparison results calculated from both static and dynamic transition probability matrices. The static matrix is calculated based on the Markov chain while the dynamic matrix is calculated based on the memory property of the particle movement. Results show that the difference in the trends of particle movement between the static and dynamic matrix calculation is very small. Besides, the particle mixing curves of the MCM and DEM have the same trend and similar numerical values, and the details show the time averaged characteristic of the MCM and also expose its shortcoming in describing the instantaneous particle dynamics in the BFB.
基金The research was supported by the National Natural Science Foundation of China (grant #40272006, 30430100, 30370184)RFDP of the Chinese Ministry of Education, and RCQJ Project of Beijing Municipal Commission of Education. Thanks are given to Prof. R. C. Fox (University of Alberta) for reading and improving the manuscript.
文摘Lacustrine deposits exposed at Daohugou, Inner Mongolia, China, have yielded superbly preserved vertebrate fossils. The fossil beds were first misinterpreted as of Early Cretaceous age, based on alleged occurrences of key fossils of the Jehol Biota. Compelling evidence revealed by more rigorous research involving regional biostratigraphy, radiometric dating, and paleontology supports the Middle Jurassic age of the fossil beds. Despite the awesome evidence for the Middle Jurassic age of the Daohugou beds, the age dispute has been resurrected recently by invoking an overturned stratigraphic sequence. A careful review of the data, however, found no evidence that this sequence has been overturned. In addition, many of the assumptions, on which the conjecture of the fossil beds being post- Middle Jurassic is imprudently based, are self-contradictory or otherwise misleading. Thus, the post- Middle Jurassic age of the Daohugou beds as an unfounded conclusion can readily be dismissed.
基金financially supported by the Special Fund for Agro-scientific Research in the Public Interest (No. 201103001)
文摘To identify a strategy for earlier sowing and harvesting of spring maize(Zea mays L.) in an alternative maize–maize double cropping system, a 2-year field experiment was performed at Quzhou experimental station of China Agricultural University in 2014 and 2015. A short-season cultivar, Demeiya number 1(KX7349), was used in the experiment. Soil temperature to 5 cm depth in the early crop growth stage, crop growth, crop yield, and water use of different treatments(plastic film-mulched raised bed(RF) and flat field without plastic film mulching(CK) in 2014; RF, plastic film-mulched flat field(FF), and CK in 2015)were measured or calculated and compared. Soil temperature in the film-mulched treatments was consistently higher than that in CK(1.6–3.5 °C in average) during the early growth stage. Crops in plastic film-mulched treatments used 214 fewer growing-degree days(GDDs) in 2014 and 262 fewer GDDs in 2015. In 2014, the RF treatment yielded 32.7%higher biomass than CK, although its 9.4% higher grain yield was not statistically significant. Also, RF used 17.9% less water and showed 33.1% higher water use efficiency(WUE) than CK. In 2015, RF and FF showed 56.2% and 49.5% higher yield, 15.0% and 4.5%lower water use(ET), and 63.4% and 75.7% higher WUE, respectively, than CK. RF markedly increased soil temperature in the early crop season, accelerated crop growth, reduced ET,and greatly increased crop yield and WUE. Compared with FF, RF had no obvious effect on crop growth rate, although soil temperature during the period between sowing and stem elongation was slightly increased. However, RF resulted in lower ET and higher WUE than FF. Effects of RF on soil water dynamics as well as its cost-effectiveness remain topics for further study.
基金Supported by the National Key Research and Development Program(2016YFB0301702)National Natural Science Foundation of China(21490584,21878298,91534105)+2 种基金Major National Scientific Instrument and Equipment Development Project(21427814)Key Research Program of Frontier Sciences of CAS(QYZDJ-SSW-JSC030)Jiangsu National Synergetic Innovation Center for Advanced Materials.
文摘The traditional fixed-bed reactor design is usually not suitable for the low tube-to-particle diameter ratios(N = D/d b 8) where the local phenomena of channeling near the wall and backflow in the bed are dominant. The recent"solid particle" meshing method is too complicated for mesh generation, especially for non-spherical particles in large random packed beds, which seriously hinders its development. In this work, a novel high-fidelity mesh model is proposed for simulation of fixed bed reactors by combining the immersed boundary and adaptive meshing methods. This method is suitable for different shapes of particles, which ingeniously avoids handling the complex "contact point" problem. Several packed beds with two different shapes of particles are investigated with this model, and the local flow in the bed is simulated without geometrical simplification. The predicted pressure drop across the fixed bed and heat transfer of the single particle are in good agreement with the corresponding empirical relations. Compared with spherical particles, the packed bed packing with pentaphyllous particles has lower pressure drop and better heat/mass transfer performance, and it shows that this method can be used for the screening of particle shapes in a fixed bed.
文摘Based on the subdivision into three members of the Lower Cretaceous Jiufotang Formation in western Liaoning, this paper deals mainly with the division and correlation of precious fossil birdand reptile-bearing beds of the formation in the Dachengzi, Chaoyang, Dapingfang.Meileyingzi and Fuxin-Yixian basins. Among them, the precious fossil-bearing beds in the Dachengzi Basin may be recognized as the Xidagou Bed of the second member and the Yangcaogoudonggou Bed of the third member; those in the Chaoyang Basin may be confirmed as the Shangheshou Bed of the second member and the Dongpochi Bed of the third member; those in the Dapingfang-Meileyingzi Basin are as the Lamagou Bed of the second member, the Huanghuagou Bed of the lower third member and the Yuanjiawa Bed of the upper third member; and those in the Fuxin-Yixian Basin are listed as the Tuanshanzi Bed of the second member and the Pijiagou Bed of the third member. Since these basins are distinctly separated and the bird and reptile fossils are mostly new genera and species, we have to use the associated fossil ostracod assemblages as index to correlate the Xidagou Bed with the Shangheshou Bed and the Lamagou Bed, and to correlate the Yuanjiawa Bed with the Yangcaogoudonggou Bed and the Pijiagou Bed. Primarily, we established the sequence of the precious fossil-bearing beds of the Jiufotang Formation in western Liaoning. They are represented by, in ascending order, the Xidagou Bed of the second member, the Huanghuagou Bed of the lower third member, and the Yuanjiawa Bed of the upper third member. Obviously, this work has significance for the study on the time-space distribution and radiation of birds and dinosaurs during the period of the middle Early Cretaceous.
基金This work is supported by the National Key Basic Research Program (2006CB701406);Natural Science Foundation of China for Youth (40403003) ;Key Project of the Natural Science Foundation of China (40332020), and is a contribution to IGCP 463.
文摘One of the new directions in the field of Cretaceous research is to elucidate the mechanism of the sedimentary transition from the Cretaceous black shales to oceanic red beds. A chemical sequential extraction method was applied to these two types of rocks from southern Tibet to investigate the burial records of reactive iron. Results indicate that carbonate-associated iron and pyrite are relatively enriched in the black shales, but depleted or absent in red beds. The main feature of the reactive iron in the red beds is relative enrichment of iron oxides (largely hematite), which occurred during syn-depostion or early diagenesis. The ratio between iron oxides and the total iron indicates an oxygen-enriched environment for red bed deposition. A comparison between the reactive iron burial records and proxies of paleo-productivity suggests that paleo-productivity decreases when the ratio between iron oxides and the total iron increases in the red beds. This phenomenon could imply that the relationship between marine redox and productivity might be one of the reasons for the sedimentary transition from Cretaceous black shale to oceanic red bed deposition.
基金supported by the National Basic Research Program of China(973 ProgramGrant No 2006CB701400)the Excellent Teacher study Program(Grant No53200959212)
文摘The planktic foraminifera of the Chuangde Formation (Upper Cretaceous Oceanic Red Beds, CORBs) as exposed at Tianbadong section, Kangmar, southern Tibet has been firstly studied for a detailed for a detailed biostratigraphy elaboration. A rich and well-preserved planktic foraminifera were recovered from the Chuangde Formation of the Tianbadong section and the Globotruncanita elevata, Globotruncana ventricosa, Radotruncana calcarata, Globotruncanella havanensis, Globotruncana aegyptiaca, Gansserina gansseri and Abathomphalus mayaroensis zones have been recognized. The planktic foraminiferal assemblage points to an early Campanian to Maastrichitian age for the CORBs of the eastern North Tethyan Himalayan sub-belt, which also provides a better understanding of the shifting progress of the Indian Plate to the north and the evolution of the Neotethyan ocean. The lithostratigraphy of the Chuangde Formation of the Tianbadong section comprises two lithological sequences observed in ascending succession: a lower unit (the Shale Member) mainly composed of purple (cherry-red, violet-red) shales with interbedded siltstones and siliceous rocks; and an upper unit (the Limestone Member) of variegated limestones. The strata of the Chuangde Formation in the Tianbadong section are similar to CORBs in other parts of the northern Tethyan Himalaya area of Asia (Gyangze, Sa'gya, Sangdanlin, northern Zanskar, etc.). The fossil contents of the Chuangde Formation in the sections (CORBs) studied provide a means of correlation with the zonation schemes for those of the northern Tethyan Himalayan sub-belt and the Upper Cretaceous of the southern Tethyan Himalayan sub-belt. Paleogeographic reconstruction for the Late Cretaceous indicates that the Upper Cretaceous Chuangde Formation (CORBs) and correlatable strata in northern Zanskar were representative of slope to basinal deposits, which were situated in the northern Tethyan Belt. Correlatable Cretaceous strata in Spiti and Gamba situated in the southern Tethyan Belt in contrast were deposited in shelf environments along the Tethyan Himalayan passive margin. CORBs are most likely formed by the oxidation of Fe(II)-enriched, anoxic deep ocean water near the chemocline that separated the oxic oceanic surface from the anoxic.
基金supported by the State Key Development Program for Basic Research of China(Grant No.2006CB202308)
文摘In recent years, great progress has been made constantly in oil and gas exploration in the Lungudong region of the Tarim Basin. However, progress has been slow in the evaluation of its main oil-producing horizons -- the Ordovician carbonate reservoir beds. Based on previous researches and on the various data such as drilling, geology and oil test, in combination with the interpretation of each single-well imaging and conventional logging data, and through analysis and comparison, the identification methods in imaging and conventional logging for four types of carbonate reservoir beds in this region are summarized in this paper. Calculation formulas for four reservoir bed parameters, i. e. shale content, porosity, permeability and oil saturation in this region are proposed; and reservoir beds in this region are divided into three levels (Ⅰ, Ⅱ and Ⅲ) by combining oil test data and logging data, The lower limits of the effective porosity of reservoir beds and the fracture porosity of effective reservoir beds are determined as 1.8% and 0.04%, respectively. The physical property parameters are calculated by conventional logging curves, and the most advantageous areas for reservoir development are predicted comprehensively. On the plane, the high-value zones of reservoir bed parameters are mainly concentrated in the N-S-trending strike-slip fault, the Sangtamu fault horst zone and near the LG38 well area; vertically, the reservoir bed parameters of the Yijianfang Formation are better than those of the Yingshan and Lianglitage formations.
文摘LA-ICPMS Zircon U-Pb dating is applied to volcanic rocks overlying and underlying the Salamander-bearing bed in the Daohugou beds of Ningcheng in Inner Mongola and Reshuichang of Lingyuan and Mazhangzi of Jianping in western Liaoning. The results indicate that the youngest age of the rocks in Daohugou of Ningcheng is 158 Ma, and the oldest one is 164 Ma. Synthesized researches indicate that the salamander-bearing beds in Daohugou of Ningcheng, Reshuichang of Lingyuan and Mazhangzi of Jianping were developed in the same period. The Daohugou beds were formed in the geological age of 164-158 Ma of the middle-late Jurassic. Whilst, the Daohugou beds and its corrdative strata should correspond to the Tiaojishan Formation (or Lanqi Formation) of the middle Jurassic in northern Hebei Province and western Liaoning Province, based on the disconformity between the Daohugou beds and its overlaying beds of the Tuchengzi Formation of Late Jurassic and the Jehol Beds of early Cretaceous, and the disconformity between the Daohugou Beds and its underlying Jiulongshan Formation, which is composed of conglomerate, sandstone, shale with coal and thin coal beds.
基金part of the research programs supported by the specialty Program of the National Basic Research Program of China(Grant No.2006CB701402)the National Science Foundation of China(Grant No.40332020).
文摘Cretaceous oceanic red beds (CORBs) represented by red shales and marls, were deposited during the Cretaceous and early Paleocene, predominantly in the Tethyan realm, in lower slope and abyssal basin environments. Detailed studies of CORBs are rare; therefore, we compiled CORBs data from deep sea ocean drilling cores and outcrops of Cretaceous rocks subaerially exposed in southern Europe, northwestern Germany, Asia and New Zealand. In the Tethyan realm, CORBs mainly consist of reddish or pink shales, limestones and marlstones. By contrast, marlstones and chalks are rare in deep-ocean drilling cores. Upper Cretaceous marine sediments in cores from the Atlantic Ocean are predominantly various shades of brown, reddish brown, yellowish brown and pale brown in color. A few red, pink, yellow and orange Cretaceous sediments are also present. The commonest age of CORBs is early Campanian to Maastrichtian, with the onset mostly of oxic deposition often after Oceanic Anoxic Events (OAEs), during the early Aptian, late Albian-early Turonian and Campanian. This suggests an indicated and previously not recognized relationship between OAEs, black shales deposition and CORBs. CORBs even though globally distributed, are most common in the North Atlantic and Tethyan realms, in low to mid latitudes of the northern hemisphere; in the South Atlantic and Indian Ocean in the mid to high latitudes of the southern hemisphere; and are less frequent in the central Pacific Ocean. Their widespread occurrence during the late Cretaceous might have been the result of establishing a connection for deep oceanic current circulation between the Pacific and the evolving connection between South and North Atlantic and changes in oceanic basins ventilation.
基金financed by the National Natural Science Foundation of China (51175499)the Beijing Natural Science Foundation, China (6112015)the Australian Centre for International Agricultural Research (ACIAR)
文摘The no-till seeders of various soil opener configurations have been shown to produce various soil physical responses in relation to soil and climate conditions, thus affecting crop performance in permanent raised beds (PRB) systems. This is particularly important in arid Northwest China where large volumes of residue are retained on the soil surface after harvest. In Zhangye, Gansu Province, China, a field trial assessed the effects of three typical (powered-chopper, powered-cutter and powered-disc) PRB no-till seeders and one traditional seeder on soil disturbance, residue cover index, bulk density, fuel consumption, plant growth, and subsequent yield. In general, seedbed conditions and crop performance for PRB no- till seeders seeded plots were better than for traditional seeded plots. In PRB cropping system, the powered-chopper seeder decreased mean soil disturbance and increased residue cover index compared to powered-disc and -cutter seeders. However, the results indicated that soil bulk density was 2.3-4.8% higher, soil temperature was 0.2-0.6℃ lower, and spring wheat emergence was 3.2-4.7% less. This was attributed to greater levels of residue cover and firmer seedbeds. Spring maize and wheat performance in the powered-cutter and -disc treatments was better (non-significant) than powered- chopper treatment. So powered disc no-till seeder, which generally provided the best planting condition and the highest yield, appeared to be the suitable seeder in heavy residue cover conditions. Considering the precision requirements for soil disturbance and residue cover, the powered strip-chopping no-till seeder could be a suitable option for PRB cropping system in Northwest China. Although these results are preliminary, they are still valuable for the design and selection of no-till seeders for PRB cropping systems in arid Northwest China.
基金supported by the National Natural Science Foundation of China(41901005)the Fundamental Research Funds for the Central Universities(SWU 118202)supported by the Ministry of Education,Science and Technological Development of the Republic of Serbia(Projects 172001 and 176006)
文摘Red beds cover approximately 9.5%of China,and are home to approximately 144 million people.In total,83%of these lands are distributed in humid regions making it an important part of research on red bed soil erosion in China in these areas.This paper presents the main types of land degradation in red bed landscapes and the status of current soil erosion in a typical red bed basin,the Nanxiong Basin located in the north of Guangdong Province,China,and establishes the connection between management strategies and regional economic development in humid red bed regions of China.The soil erosive modulus was calculated in the Nanxiong Basin by using RUSLE(The Revised Universal Soil Loss Equation).The results of overlapping analyses demonstrated that appropriate measures,such as the Return Farmland to Forests initiative,should be taken at the junction of central red bed areas and mountainous areas in order to mitigate current soil erosion.Two examples are presented to demonstrate this:the tourism development in Mt.Danxiashan,a noted scenic mountainous area near Nanxiong Basin,and the land degradation mitigation in the Nanxiong Basin.Both examples promote local economic growth while simultaneously protecting the environment.A‘stakeholder'strategy is pursued at Mt.Danxiashan,which can help residents to understand their positive effects on the environment as well as increase their income.The second example,in Nanxiong City,showcases how local farmers became stakeholders by implementing contract responsibility and self-support systems for economic forests and terraced land in the 1980s.
基金This work was financially supported by the Education Department of China (No.00020)
文摘A heat pump assisted fluidized bed grain drying experimental system wasdeveloped. Based on this system, a serial of experiments was performed under four kinds of air cycleconditions. According to the experimental analysis, an appropriate drying medium-air cycle for theheat pump assisted fluidized bed drying equipment was decided, which is different from the commonlyused heat pump assisted drying system. The experimental results concerning the drying operationperformance of the new system show that the averaged coefficient of performance (COP) can reach morethan 2.5. The economical evaluation was performed and the power consumption for removing a kilogramwater from grains was about 0.485 kW-h/kg (H_2O), which shows its reasonable commercial efficiencyand great application potentiality in future market.
基金financially supported by the Ministry of Education of China(Grant No.6141A02022337)
文摘Torpedo anchors have been used in mooring systems for deep-water oil and gas projects owing to their prominent advantages, such as low cost and easy installation. The maximum force of torpedo anchors is crucial not only to the safety and stability of vessels and other marine facilities, but also for an economical design. It is necessary to develop reliable formula for fast predicting their maximum inclined force of a torpedo anchor in cohesive beds. In this study, the maximum inclined force of a torpedo anchor vertically embedded in cohesive beds was extensively investigated. 316 sets of inclined pullout laboratory tests were carried out for 9 differently shaped torpedo anchors which were vertically embedded in different cohesive beds. The loading curves were automatically acquisitioned and their characteristics were analyzed. The load angle relative to the horizontal varied from 20° to 90°. A new formula for fast calculating the maximum inclined force of the torpedo anchor vertically embedded in cohesive beds was obtained based on force analysis and a nonlinear regression on the data from the present and other studies. Effect aspects on the tests are discussed and further studies are highlighted.