• Journal of the Korean Society of Tobacco Science
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• v.28 no.1
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• pp.36-42
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• 2006

The papermaking process for a reconstituted tobacco sheet (RECON) has been preferred more because of the various merits such as a wide range of Recon products with better quality. The screw press is one of the very important process in RECON making process which divides the mixed raw materials into the soluble material and the insoluble material and could greatly affect the productivity and product quality. In this study, the characteristics of the screw press process in a Recon making mill were evaluated for two different RECON products. Three different efficiency index were proposed for the more detailed analysis of the screw press process. The result showed that the difference in the raw material might result in the difference in the efficiency and the properties of the extracts and the filter cake, especially in the HWS. The washing technique which applied in this experiment showed the amount of residual HWS in the fiber portion were not much changed by the each steps of the screw press.

• Journal of the Korean Society of Tobacco Science
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• v.28 no.2
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• pp.117-123
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• 2006

The pulping process in a papermaking process for a reconstituted tobacco sheet (RECON) was evaluated. For the practical information, the experiments were conducted in a real mill. Two pulping conditions were chosen and changed depending on the feasibility, such as the pulping temperature and the properties of pulping water. The higher pulping temperature resulted in the easier dissolution of solubles from the raw materials. However, the efficiency of screw press process was decreased by the higher pulping temperature, which resulted in the reduction of the HWS and the concentration in the #1 screw press filtrate. The addition of SEL(Strong extracted liquor) to pulper affected the efficiency of dissolution and the final concentration of #1 screw press filtrate. Although the higher SEL resulted in the less dissolution of the solubles from the raw materials, the concentration of the #1 screw press filtrate was greatly increased by the higher addition of SEL, which could provide much better efficiency to the following evaporation process of the filtrate and could increase the whole productivity.

• Journal of Animal Environmental Science
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• v.20 no.1
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• pp.1-8
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• 2014

The study on design criteria of solid-liquid separator for dairy farms was done by testing various screens, presses, and RPMs of screw auger with remodeled screw-press type pig-manure separator. The moisture content of separated solid increase from 68.3% to 74.2% as auger rotating speed increased from 9.8 to 29.2 RPM at 34.8 kPa of pressure and 1.0 mm of slit wedge wire screen condition. The moisture contents of separated solid were 72~77%, work efficiencies were 16~18 kg/min at 1.0 mm of slit wedge wire screen. The efficiency was higher than one at 0.5 mm of slit wedge wire screen, which was used to separate for pig manure. The best work efficiency was 18 kg/min at 42.5 kPa, 1.0 mm slit screen. The separated solid moisture content was 75% at this condition.

• Computers and Concrete
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• v.29 no.6
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• pp.361-374
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• 2022

On the premise of ensuring that the automatic and quantitative discharging function of concrete conveyors is met, the accuracy of the weight forecast by the mathematical model of the screw conveying volume is improved, and the error of the weight of the concrete parts and the accumulation thickness is reduced. In this paper, the discrete element method (DEM) is used to simulate the macroscopic flow of concrete. Using the concrete discrete element model, the size of the screw conveyor is set, and establish the response model between the influencing factors (process and structure) and the concrete mass flow rate according to the design points of the screw discharging experiment. The nonlinear data fitting method is used to obtain the volumetric efficiency function under the influence of process and structural factors, and the traditional screw conveying volume model is improved. The mass flow rate of concrete predicted by the improved mathematical model of screw conveying volume is consistent with the test results. The model can accurately describe the conveying process of concrete and achieve the purpose of improving the accuracy of forecasting the weight of discharged concrete.

• Advances in Computational Design
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• v.4 no.4
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• pp.381-395
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• 2019

This paper proposes a new approach to model the screw joints of integrated ceilings via the finite element method (FEM). The simulation models consist of the beam elements. The screw joints used in the main bars and cross bars and in the W bars and cross bars are assumed to be rotation springs. The stiffness of the rotation springs is defined according to the technical standards proposed by the National Institute for Land and Infrastructure Management of Japan. By comparing the results of the sheer tests and the simulation models, the effectiveness and efficiency of the simulation models proposed in this paper are verified. This paper indicates the possibility that the seismic performance of suspended ceilings can be confirmed directly via beam element models using FEM if the stiffnesses of the screw joints of the ceiling substrates are appropriately defined. Because cross-sectional shapes, physical properties, and other variables of the ceiling substrates can be easily changed in the models, it is expected that suspended ceiling manufactures will be able to design and confirm the seismic performance of suspended ceilings with different cross-sectional shapes or materials via computers, instead of spending large amounts of time and money on shake table tests.

• Structural Engineering and Mechanics
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• v.46 no.3
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• pp.387-402
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• 2013

A dynamic load protocol has been used to experimentally simulate fatigue behavior in cold-formed metal panels with screwed connections under wind loading. The specific protocol adopted is an adaptation of SIDGERS, originally developed for non-metallic membranes, which is composed of levels each under increasing load values. A total of 19 tests were performed on 3.35 m long by 0.91 m wide panels, identified as Type B-wide rib and Type E, both with screw connections at the edge and at the center, thus conforming two-span specimens. In some configurations the panels were fixed at the valleys, whereas crest-fixed connections were also investigated. Reinforcing the connections by means of washers was also investigated to evaluate their efficiency in improving fatigue capacity. The experimental results show maximum load capacities in improved connections with washers of approximately twice of those with classical connections.

• Computers and Concrete
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• v.30 no.5
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• pp.311-321
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• 2022

The interfacial bond strength of partially encased composite (PEC) structure tends to 0, therefore, the cast-in-place concrete theoretically cannot embody better composite effect than the fabricated structure. A total of 12 specimens were designed and experimented to investigate the energy dissipation and damage of fabricated PEC beam through unidirectional cyclic loading test. Because the concrete on both sides of the web was relatively independent, some specimens showed obvious asymmetric concrete damage, which led to specimens bearing torsion effect at the later stage of loading. Based on the concept of the ideal elastoplastic model of uniaxial tensile steel and the principle of equivalent energy dissipation, the energy dissipation ductility coefficient is proposed, which can simultaneously reflect the deformability and bearing capacity. In view of the whole deformation of the beam, the calculation formula of energy dissipation is put forward, and the energy dissipation and its proportion of shear-bending region and pure bending region are calculated respectively. The energy dissipation efficiency of the pure bending region is significantly higher than that of the shear-bending region. The setting of the screw arbors is conducive to improving the energy dissipation capacity of the specimens. Under the condition of setting the screw arbors and meeting the reasonable shear span ratio, reducing the concrete pouring thickness can lighten the deadweight of the component and improve the comprehensive benefit, and will not have an adverse impact on the energy dissipation capacity of the beam. A damage model is proposed to quantify the damage changes of PEC beams under cyclic load, which can accurately reflect the load damage and deformation damage.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.2
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• pp.65-72
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• 2008

This work evaluated the extractability of tobacco stem biomass for the papermaking type Reconstituted Tobacco Sheet(RTS). The effects of the soaking conditions on the hydration of stem biomass and the effects of the hydrated state on the mechanical extraction were investigated. In order to simulate the mechanical expression process of a papermaking type RTS mill, for example, the screw press process, the novel mechanical pressing analyzer was developed for this study. The hydration of stem biomass by soaking process was greatly affected by the soaking time and the soaking temperature. The longer soaking time and the higher soaking temperature resulted in the higher hydrated stem biomass. Since the higher hydrated stem had more combined water in the inner structure and resulted in the more flexible structure, the higher hydrated stem leaded to the more compressed filter cake and the higher water contents in the filter cake after the mechanical pressing. The pilot pulping experiments showed the difference in hydration and extractability between burley and bright tobacco stem. The bulkier structure of the burley stem resulted in the faster hydration by pilot pulping and leaded to the larger reduction in water soluble components. And the hydration process showed the major influence on the separation efficiency of water soluble components.