Multilayer Bed Research Articles

다층베드시설을 이용한 묘삼 생산 시 미기상 환경과 생육특성

다층베드시설을 이용한 묘삼 생산 시 미기상 환경과 생육특성

The Spatial Distribution of CBM Systems under the Control of Structure and Sedimentation: The Gujiao Block as an Example

A multilayer coal bed methane system with a complex superimposed relationship developed vertically in the Gujiao block. Taking the cumulative thickness of mudstone between neighbouring coal seams and open faults as object of research, the key strata for the division of different CBM systems was defined. The connection of an open fault for the fluid pressure system and the spatial distribution of the CBM system were analysed. The results showed that the porosity of compact mudstone is extremely low. When the mudstone thickness of the roof and floor increases, the gas content increases. Taking the Lijiashe and Wangzhimao faults as the boundary lines, the fluid pressure gradient between the Shanxi and Taiyuan formations is less than 0.08 MPa /100 m in the northern fracture zone, such as the Zhenchengdi, the Xiqu, the Tunlan, and the northern Dongqu well fields. The vertical gas units of different strata may belong to the same CBM system. The structure is simple in the southern Lijiashe fault. The vertical gas units in the southern Lijiashe fault belong to different CBM systems. Combined with the minimum thickness of the mudstone layer (2 m) and coal seam (0.5 m) standards, the spatial distribution of CBM systems was analysed.

Masonry walls with a multi-layer bed joint subjected to in-plane cyclic loading: An experimental investigation

A series of static-cyclic shear tests on full-scale unreinforced masonry (URM) walls with multi-layer bed joints have been performed within a research project on the seismic behaviour of unreinforced masonry walls with soft layer membrane placed in the bed joint to induce sliding. Walls were made using typical perforated Swiss clay blocks and standard cement mortar and the so-called multi-layer bottom bed joints, which comprise a core soft layer protected by two layers of extruded elastomer and placed in the middle of mortar joint. The preliminary testing phase was aimed at choosing the most suitable core soft layer type among the four types considered (rubber granulate, cork, cork-rubber granulate and bitumen). The main testing phase comprised five tests on storey-high URM specimens with rubber granulate core soft layers performed to investigate the influence of the size, the pre‐compression level and the aspect ratio on the seismic behaviour of URM walls with a multi‐layer bed joint. Sliding occurred in all tested specimens. However, the final failure mode as well as the displacement capacity of test specimens were governed by the extent of shear and tensile (vertical) cracks that developed from the bottom brick course. The response of specimens can be interpreted using a multilinear horizontal force-displacement response idealization, whose parameters can be estimated using the proposed equations.

Effect of CaO on the reduction behaviour of iron ore–coal composite pellets in multi-layer bed rotary hearth furnace

ABSTRACTThe effect of CaO on the reduction behaviour of iron ore–coal composite pellets has been studied in a laboratory scale multi-layer bed rotary hearth furnace at 1250°C for 20 min. Reduced pellets have been characterised through weight loss, porosity measurement, phase analysis by XRD, and morphology study by SEM. The addition of CaO to the composite pellets showed different effects at different carbon levels. For higher carbon-containing pellets (C/Fe2O3 molar ratio at the upper stoichiometric level of 3), the addition of CaO increased the extent of reduction for all three layers significantly up to a certain limit (4 wt-%); and thereafter the degree of reduction is decreased with a further increase in CaO percentage in the pellets. For low carbon-containing pellets (C/Fe2O3 molar ratio of 1.66), the addition of CaO to the pellets did not show any beneficial effect.

Effect of Amount of Carbon on the Reduction Efficiency of Iron Ore-Coal Composite Pellets in Multi-layer Bed Rotary Hearth Furnace (RHF)

The effect of carbon-to-hematite molar ratio has been studied on the reduction efficiency of iron ore-coal composite pellet reduced at 1523 K (1250 °C) for 20 minutes in a laboratory scale multi-layer bed rotary hearth furnace (RHF). Reduced pellets have been characterized through weight loss measurement, estimation of porosity, shrinkage, qualitative and quantitative phase analysis by XRD. Performance parameters such as the degree of reduction, metallization, carbon efficiency, productivity, and compressive strength have been calculated to compare the process efficacy at different carbon levels in the pellets. Pellets with optimum carbon-to-hematite ratio (C/Fe2O3 molar ratio = 1.66) that is much below the stoichiometric carbon required for direct reduction of hematite yielded maximum reduction, better carbon utilization, and productivity for all three layers. Top layer exhibited maximum reduction at comparatively lower carbon level (C/Fe2O3 molar ratio 2.33). Correlation between degree of reduction and metallization indicated non-isothermal kinetics influenced by heat and mass transfer in multi-layer bed RHF. Compressive strength of the partially reduced pellet with optimum carbon content (C/Fe2O3 molar ratio = 1.66) showed that they could be potentially used as an alternate feed in a blast furnace or any other smelting reactor.

Masonry elements with multi-layer bed joints: Behaviour under monotonic and static-cyclic shear

The goal of the research project presented here is to investigate the effect of multi-layer bed joints on the shear behaviour of unreinforced masonry elements subjected to cyclic actions, and to assess the shear mechanical characteristics of multi-layer bed joints. Such joints consist of a core soft layer protected with two thin extruded elastomer membranes, which in turn are placed in a bed mortar joint. The extruded elastomer membranes are employed to prevent and/or limit the deterioration of the core soft layer during the cycling action, which has been observed in previous investigations. Five different core soft layer materials, namely rubber granulate, cork-rubber granulate, cork, bitumen and polyvinylchloride were employed. A total of 57 clay block masonry triplets were subjected to both monotonic and static-cyclic loading under varying levels of pre-compression.The shear behaviour of the specimens was greatly influenced by the applied pre-compression level and by the loading speed. Increasing the level of pre-compression leads to the higher values of shear strength. The same is true for increasing loading speed. Further, for the prediction of the failure shear force a Mohr–Coulomb failure criterion with zero cohesion can be applied. Finally, experimental findings showed that extruded elastomer layers largely fulfilled the intended protective role.The results indicate that multi-layer bed joints with adequate material properties have the potential to change the typical brittle shear response of unreinforced masonry walls to a more desirable quasi-ductile behaviour. Moreover, based on the observed hysteretic behaviour, considerable energy dissipation could be expected in masonry structures with multi-layer bed joints. Such behaviour would be desirable for enhanced seismic performance.

Analysis of gas dehydration in TSA system with multi-layered bed of solid adsorbents

The paper presents theoretical analysis of adsorptive drying of gaseous mixtures, containing water vapor and volatile organic compound (VOC), in a cyclic thermal swing adsorption (TSA) system. The system consists of two fixed bed adsorption columns each containing three layers of different adsorbents. The first two layers consist of silica gel and zeolite 13X, as adsorbents of water vapor. The third layer consists of activated carbon, as an adsorbent of the organic component (benzene). A non-equilibrium, non-isothermal, and non-adiabatic mathematical model is developed in order to simulate the performance of a TSA gas drying unit employing the layered bed. The results of the computer simulation show that the layered bed, containing silica gel and zeolite 13X, reveals a longer water vapor breakthrough time compared with those for single bed with silica gel and zeolite 13X, and that desorption behavior of the layered bed is significantly enhanced compared with single bed. The quantity of adsorbed benzene on silica gel and zeolite 13X is considerably smaller than that on activated carbon. The validation of the modeling results showed fairly good agreement between experimental and theoretical data for both the zeolite 13X and layered bed containing silica gel and zeolite 13X.

Preliminary Thermo-mechanical Analysis of Water Cooled Ceramic Breeder Blanket for China Fusion Engineering Test Reactor

Bridging from ITER to DEMO, China Fusion Engineering Test Reactor aims at tritium self-sufficiency which is one of the main functions of blanket. The structure and thermo-mechanical performance influences strongly the operation and tritium breeding of blanket. In this paper, Water Cooled Ceramic Breeder blanket was designed with multilayer mixed pebble beds. And preliminary thermo-mechanical analysis has been done by the coupling of ANSYS finite element (FE) model and self-developed finite difference (FD) code under normal steady state condition. The results showed that the temperature distribution of the FE model corresponds well to that of the FD code. The obtained equivalent stress of the blanket is presented and critically verified the compliance with the SDC-IC code as reference criteria. At last, possible improvements such as adding fillets and plug-in materials are proposed to ameliorate the structure.

Geographical variation of shell thickness in the mussel Perumytilus purpuratus along the southeast Pacific coast.

At broad geographical scales, the variation in bivalve shell thickness can be modulated by environmental factors that vary with latitude, such as sea surface temperature (SST), seawater pH, or calcium carbonate availability. Mussels usually form multilayered beds, and shell thickness is also expected to be affected by density and layering due to intraspecific competition. In this work, we explored the geographical variation of shell thickness in the intertidal mussel Perumytilus purpuratus between 18° and 42°S along the southeastern Pacific coast. We tested the hypothesis that there was a positive relationship between shell thickness and SST, and then we explored other variables that could have an effect on thickness, such as density, number of layers, and others environmental variables (pH and calcite concentration). The expected positive linear relationship between shell thickness and sea surface temperature was not found, but when the other population variables were included in the analysis, an unexpected inverse SST-thickness relationships appeared as significant, probably because this species could be adapted to colder and more acid seawater as are those of the tips of South America. Thickness was also negatively affected by density, which was expected for a gregarious species showing high intraspecific competition. Finally, our results highlight the importance of including density and crowding effects when macroscale patterns are explored, particularly in gregarious species, since these patterns could also be modulated by density-dependent processes, which might then override latitudinal trends of shell thickness when they are not included in the analyses.

Mathematical Model to Estimate the Rate Parameters and Thermal Efficiency for the Reduction of Iron Ore–Coal Composite Pellets in Multi-layer Bed at Rotary Hearth Furnace

Reduction of iron ore–coal composite pellets at a rotary hearth furnace (RHF) could be an energy efficient process under optimized design and operating conditions. The present study aims to analyze such process through process models for optimization of thermal efficiency. In the present article, a mathematical model has been described to calculate the rate parameters, evolution of various phases, temperature profile, and thermal efficiency of the process. Experiments have been carried out for reduction of iron ore–coal composite pellets in multi-layers at laboratory scale RHF. It has been observed that while the total average time of reduction for three layer bed at 1,200 °C is 48 min, the average time of reduction at 1,300 °C is estimated as 11 min only. The thermal efficiency of the process is found to be maximum for three layer bed and least for the single layer bed. Extra fuel in terms of carbon equivalent has also been reported.

Research of Interlayer Interference and Development Strategy of Multilayer Commingled Production Gas Reservoir

Sebei gas field is featured with the characteristics of the shallow-buried gas reservoir, long gas containing well section, multilayer gas reservoirs beds, the complicated gas/water contact distribution, the water produced obviously, sands produced frequently from the gas wells and the multi-layers gas reservoir extracted unbalancedly in the developing process. For these reasons, the paper proposed the method that interlayer interference coefficients are defined with statistical function. Combined with the data of the sand-layers profile test, the effects of the numbers of different sand-lays, the perforated thickness, the perforated interval length and permeability contrast on the interlayer interference are evaluated and these permeability parameters are optimized.

Study of reduction behaviour of prefabricated iron ore–graphite/coal composite pellets in rotary hearth furnace

In the present study, the reduction kinetics of prefabricated iron ore–graphite/coal composite pellets of different shapes has been studied in a rotary hearth furnace (RHF). Commercial processes involving the RHF such as ITmk3/FASTMET have major problems of low productivity owing to significant heat and mass transfer resistance through the multilayer bed and consequently limited pellet layers over the hearth. In the present investigation, an attempt has been made to improve the heat and mass transfer in such system by increasing the specific surface area of individual pellets. Both the iron ore–graphite and iron ore–coal composite pellets have been reduced in an RHF at a maximum temperature of 1200°C. The ore–coal composite showed much higher degree of reduction (81%) over ore–graphite composite pellets (61%). The tablet shaped pellet with the highest specific surface area displayed a higher degree of reduction than the cylinder or sphere shaped pellets. Although no physical slag metal separation was visible, X-ray diffraction and SEM/EDX of reduced particles indicated separation at the microlevel. Higher amount of reduction and liquid silicate formation for tablet shaped pellets, in comparison with spherical and cylindrical shaped pellets, lay the foundation of a novel process flow scheme involving the use of prefabricated pellets in the RHF.

Iterative methods for solving seepage problems in multilayer beds in the presence of a point source

This work is devoted to solving steady-state seepage problems of an incompressible fluid that obeys a nonlinear multivalued filtration law with limit gradient in a multilayer bed in the presence of a point source. The seepage problem is formulated as a mixed variational inequality with an inversely strongly monotone operator in a Hilbert space. An iterative splitting method is proposed to solve the variational inequality. Unlike the earliermethods, the method proposed allows one to find not only approximate values of the fluid pressure, but also the filtration rates, in particular, on the sets corresponding to multivalued points in the filtration law. The convergence of the method is analyzed.

Use of shell-shape to discriminate betweenBrachidontes rodrigueziiandBrachidontes purpuratusspecies (Mytilidae) in the transition zone of their distributions (south-western Atlantic)

Mussels are important components of rocky shore assemblages throughout the world. Several mytilid species are found as multilayered beds in the intertidal along the coasts of the south-western Atlantic. However, in contrast to the north communities in the Pacific and Atlantic, those of the south-western Atlantic are dominated by species of small size, locally named mejillines. These mid-intertidal beds attached to consolidated substrates are dominated by virtual monocultures of two small-sized species ofBrachidontes: B. rodriguezii(d'Orbigny, 1842) andB. (Perumytilus) purpuratusLamarck, 1819, respectively distributed in the warm and cold temperate sectors of the south-western Atlantic; both coexisting in the transition zone between 40° and 44°S latitude. Nevertheless, there has been some confusion about the separation ofB. rodrigueziiandB. purpuratus, as well as about the boundaries of their distribution ranges in the south-western Atlantic. Here, on the basis of a morphogeometric analysis of shell morphology, we describe a feasible way for the identification of both species.

현장조사와 침투모형시험을 통한 방조제 침투특성 연구

본 연구는 다층지반으로 구성된 방조제의 침투변화에 따른 안정성을 검토하기 위하여 현장조사와 역해석 방법으로 투수계수와 침투수량을 결정하고, 제체의 변형량과 유실량 측정을 위하여 침투모형시험을 수행하여 가장 합리적인 수치해석 방법을 결정하였다. 검토결과 방조제는 다층지반구조물로 투수계수 차이에 의해 바닥보호공과 성토체 경계부에서 유실이 발생하고 이로 인해 방조제의 변형이 발생한다는 것을 예측할 수 있었다. 한편 침투모형 시험에 대한 수치해석결과 한계유속에 의한 방법은 실측치가 해석값보다 작게 나왔으나 그 경향이 유사하여 실제 단면에 적용 가능할 것으로 판단되었다. The purpose of this study is to decide the permeability and the rate of flow in a way of both site investigation and backward analysis and the most reasonable numerical analysis by performing a seepage model test for measuring the deformation swept volume of the embankment body in order to review a stability of the sea dyke being composed of multi-layers depending on variation of infiltration. As a result of the review, it could be forecasted that sweeping loss would be taken place at the boundary between bed protection works and embankment materials of the sea dyke due to a permeability difference of the multi-layered bed foundation structures and the sea dyke deformation would be occurred as a result thereby. As result of a numerical analysis for the seepage model test, it could be observed that critical velocity method was found to be smaller than the numerical analysis value but its tendency was similar and therefore it was judged that this method could be applied for the actual cross section.

Formation conditions and geological characteristics of deep giant gas provinces in the Kuqa foreland thrust belt

Abstract A series of seismic exploration technologies, such as “wide line and big combination” mountainous seismic acquisition, high steep structure pre-stack depth migration processing and deep tectonic modeling, were used to explore Kuqa deep structures. Pre-salt deep structures were preliminarily confirmed and a group of large structural traps were found. The research shows that the Kuqa foreland thrust belt is favorable for forming giant gas accumulations. Large-scale imbricated thrust systems can provide traps for large-scale oil and gas accumulation; excellent hydrocarbon source conditions and later intense charges of gas provide sufficient hydrocarbon reserves; the deep mass effective reservoir sandstone works as good reservoir volume for giant gas accumulations and thick gypsum deposits serve as good cap rocks. The geological characteristics of deep pre-salt structure giant gas accumulations typically have hydrocarbon distributions controlled by structural traps and structural gas reservoirs are dominant, reservoir properties of the deep thrust belts are generally poor, with fractures being the important controlling factor for hydrocarbon enrichment, oil and gas distribution is characterized by joint control of source and cap rock, stacking of multi-layer beds, and overall beds containing gas. Reserves are large, and single well productivity is high.

Micropatterned antibody-terminated nanocomposites (MANs) fabricated using layer-by-layer lift-off (LBL-LO) technique

Patterned functional biomolecular surfaces have been created using a wide range of fabrication methods for applications in cell-based studies, with the most common methods based on photolithography or soft lithography. In this study, a simple fabrication method combining photolithography, layer-by-layer (LbL) self-assembly, and photoresist lift-off (LO) was used to create spatially defined nanocomposite micropatterns of antibodies on polyelectrolyte-protein multilayer beds. The two components of the micropatterned surfaces consisted of an anti-CD44 rat monoclonal antibody atop a vitronectin-coated multilayer film and an anti-rat osteopontin (MPIIIB10(1)) anitibody atop a fibronectin-coated multilayer film. The micropatterned antibody-terminated nanocomposites (MANs) were characterized using bright field microscopy, surface profilometry, and atomic force microscopy. The results demonstrate that LbL-LO method can be successfully used to create patterns of proteins and antibodies in precise spatial arrangements. The MAN surfaces can be utilized in many bionanotechnology applications, including patterned cell cocultures or tricultures, cytotoxicity testing, drug screening, and biosensing. In addition, the general fabrication approach used in this study is applicable to other antibodies and other ligands.

Wave Damping over a Multilayered, Permeable Seabed

Abstract In this study, a wave-damping rate was derived for waves propagating over a multilayered, permeable seabed of finite depth. For a single-layer bed, a monogram is presented for the relationship between the wave-damping rate and the relative water depth for various depths of the permeable bed. The derived damping rate was used in the extended mild-slope equation to calculate wave dissipation over the permeable bed. For a single-layer bed, the result from the extended mild-slope equation model was compared with the result from the integral equation method and showed good agreement. The extended mild-slope equation model was also used to examine the wave transmission over a permeable shoal with a various number of layers, each with a different permeability. In general, short waves are more influenced by the permeability of the shoal than long waves unless the water depth is so great that the influence of the permeable bed on the surface water waves disappears. For a multilayered bed, the influences o...

Dual mode roll-up effect in multicomponent non-isothermal adsorption processes with multilayered bed packing

Roll-up is a common phenomenon occurring in multicomponent adsorption processes when the concentrations of some components at the outlet of the adsorber exceed their inlet levels. Previous investigations attributed the roll-up effect typically to the displacement of one component by another because of the difference in adsorption affinities or diffusivities. In this work, we report the existence of a peculiar type of roll-up caused by thermal effect solely in our multicomponent non-isothermal breakthrough experiments where the light component CO 2 was swept off by a pure thermal wave developed from water vapour adsorption. Even though, the formation of a pure thermal wave is well known, it does not lead to the above roll-up without a multilayered bed packing. To our surprise, a secondary roll-up of CO 2 caused by H 2O displacement was also observed, since the front of the water concentration wave ran behind its thermal wave in our case. The parameters affecting the formation of this special dual mode roll-up were investigated and summarised. This work will give guidance to the design of multilayered cyclic adsorption processes, e.g. determination of layering ratios and duration of the feed step.

A model-based investigation of the potential advantages of multi-layer packed beds in solid-state fermentation

We use a mathematical model, based on the N-tanks-in-series approach, to evaluate the potential advantages that can be obtained in solid-state fermentation processes by operating packed-bed bioreactors as multi-layer beds. We explore classical operation, in which air is blown unidirectionally through a substrate bed that remains immobile, with two strategies that involve movement of the layers. The first strategy involves batch operation, in which the positions of the layers are changed at 1 h intervals, in a cycling motion. The second strategy involves continuous plug-flow of the layers, with the regular addition of new layers at the air outlet and removal of spent layers at the air inlet. Under the conditions of the simulation, the rate of metabolic heat generation during the steady state of the continuous plug-flow process is only 60% of the peak value predicted for classical operation. As a result, the maximum bed temperature in the continuous plug-flow process is 4.5 °C lower than that predicted for classical operation. We conclude that the operation of multi-layer packed beds in the continuous plug-flow mode can improve bioreactor performance significantly.