Economic Analysis of Atomization Drying of Concentrated Solution Based on Zero Discharge of Desulphurization Wastewater

With the improvement of environmental protection requirements, more and more attention has been given to desulphurization wastewater with zero discharge in coal power plants. Atomization drying is part of the main zero discharge technologies at present. Economic analysis of the atomization drying of desulphurization wastewater is beneficial to the formulation of an appropriate operation scheme and to the reduction of operation costs. The economic analysis and sensitivity analysis of different operating conditions such as unit load, the handling capacity of concentrates, and the temperature of the extracted flue gas in the atomization drying process of concentrated desulfurized wastewater were carried out in this paper. The main cost of the drying process came from the influence of flue gas extraction on the overall heat transfer in the boiler, resulting in the decrease in power generation revenue, which can reach more than 80%. The operating cost of auxiliary machinery was relatively low. The cost of treatment for per ton of concentrates increased first and then decreased with the increase in temperature of the extracted flue gas, and it decreased with the increase in the handling capacity of the concentrates. The effect of a unit load on the treatment cost was also related to the temperature of the extracted flue gas, and the optimal flue gas temperature increase to higher temperatures as the unit load decreased. The minimum treatment costs per ton of concentrate ranged from CNY 143.54/t to CNY 158.77/t under different unit loads. Sensitivity analysis showed that the temperature of the extracted flue gas had the greatest impact on treatment cost, and its sensitivity coefficient was 0.0834. The ways in which to improve economic benefits were discussed.

Development of a Gaussian Process Model as a Surrogate to Study Load Bridging Performance in Racked Pallets

Current pallet design methodology frequently underestimates the load capacity of the pallet by assuming the payload is uniformly distributed and flexible. By considering the effect of payload characteristics and their interactions during pallet design, the structure of pallets can be optimized and raw material consumption reduced. The objective of this study was to develop a full description of how such payload characteristics affect load bridging on unit loads of stacked corrugated boxes on warehouse racking support. To achieve this goal, the authors expanded on a previously developed finite element model of a simplified unit load segment and conducted a study to screen for the significant factors and interactions. Subsequently, a Gaussian process (GP) regression model was developed to efficiently and accurately replicate the simulation model. Using this GP model, a quantification of the effects and interactions of all the identified significant factors was provided. With this information, packaging designers and researchers can engineer unit loads that consider the effect of the relevant design variables and their impact on pallet performance. Such a model has not been previously developed and can potentially reduce packaging materials’ costs.

Optimization of Loading Condition for Maxillary Molar Intrusion with Midpalatal Miniscrews by Using Finite Element Analysis

An anterior open bite is one of the most difficult malocclusions in orthodontic treatment. For such malocclusion, orthodontic miniscrew insertion into both buccal and palatal alveolar regions has been indicated for molar intrusion, but it involves a risk of tooth root injury. To solve the problem, a midpalatal miniscrew-attached extension arm (MMEA) is adopted. However, this method causes palatal tipping of the molar because intrusive loads were applied only from the palatal side. Currently, a transpalatal arch is added to avoi0d tipping movement, but it induces the patient’s discomfort. Hence, the objective of this study was to evaluate the loading conditions for maxillary molar intrusion without tipping movement, only by MMEA through finite element (FE) analysis. FE models of maxillary right first molar and surrounding tissues were created. Three hook positions of MMEA were set at 6.0 mm perpendicular intervals in the occluso-apical direction along the mucosal contour. An intrusive unit load was applied from the palatal side of the molar, and various counter loads were applied from the buccal side. An optimal counter load for molar intrusion without palatal tipping was observed in each hook position. In conclusion, an ideal maxillary molar intrusion can be achieved only by MMEA with an optimal counter load.

Theoretical development of a stiffness decomposition method for calculating the displacement of complex bending structures

It is very difficult to provide analytical displacement solutions for complex bending structures, such as beams with variable cross-sections, in structural analysis. The common methods used for such analysis—the direct integration method and the conventional graph multiplication method—have disadvantages of inefficiency and large computational costs. Therefore, a new approach called the stiffness decomposition method was proposed to overcome these shortcomings. The fundamental principle of this new approach was derived based on the unit load method. The general calculation equation of displacement was derived and provided for general n-segment complex bending structures, and an operational procedure for this method was constructed to facilitate its application. Then, the method was applied to two case studies involving classic complex bending structures. The results showed the correctness and effectiveness of the proposed method. The stiffness decomposition method was simpler and more efficient than the other two methods: the number of computations required by the stiffness decomposition method accounted for only 47.4% to 84.0% of the number of computations required by the other methods in the two case studies. The clear mathematical and mechanical derivation of the proposed method makes it easy to understand. Furthermore, the simplicity and practicality of this method make it extensively applicable.

Analysis of the advanced oxygenate water level control scheme of the engineering supercritical unit

The oxygenate water level is an important adjustment parameter in the operation of the fire generator set, and the water level may result in the safety of the water pump. The high water level will not only affect the oxygen effect, but it is also possible to cause the water shot to the steam turbine to cause a water shot or give the water tank full water, oxygenate vibration, drain and vapor with water. When the load is low (generally 35% rated load), the oxygenate water level is controlled by large and small valve, condensate pump variable frequency control condensed water drum pressure. When the unit load is high (greater than 35 rated load), the oxygenate water level is controlled by the condensed water pump, the large valve and small valve controls condensed water drum pressure.

Investigation of the Effect of Pallet Top-Deck Stiffness on Corrugated Box Compression Strength as a Function of Multiple Unit Load Design Variables

Unit loads consisting of a pallet, packages, and a product securement system are the dominant way of shipping products across the United States. The most common packaging types used in unit loads are corrugated boxes. Due to the great stresses created during unit load stacking, accurately predicting the compression strength of corrugated boxes is critical to preventing unit load failure. Although many variables affect the compression strength of corrugated boxes, recently, it was found that changing the pallet’s top deck stiffness can significantly affect compression strength. However, there is still a lack of understanding of how these different factors influence this phenomenon. This study investigated the effect of pallet’s top-deck stiffness on corrugated box compression strength as a function of initial top deck thickness, pallet wood species, box size, and board grade. The amount of increase in top deck thickness needed to lower the board grade of corrugated boxes by one level from the initial unit load scenario was determined using PDS™. The benefits of increasing top deck thickness diminish as the initial top deck thickness increases due to less severe pallet deflection from the start. The benefits were more pronounced as higher board grade boxes were initially used, and as smaller-sized boxes were used due to the heavier weights of these unit loads. Therefore, supposing that a company uses lower stiffness pallets or heavy corrugated boxes for their unit loads, this study suggests that they will find more opportunities to optimize their unit loads by increasing their pallet’s top deck thickness.

Numerical stress analysis of tubular joints

The finite element analysis (FEA) presented in this paper pertains to the stress analysis of both the welded tubular T and X joints and is aimed to assess both the importance of the presence of the weld geometry and the suitability of shell and solid elements with regards to the FEA of welded tubular joints and, additionally, to confirm or dispute a correlation between the standards AWS D1.1 and DNVGL-RP-C203 with regards to the minimum size of the weld geometry. Using symmetry, three unit-load cases are investigated: axial loading, in-plane and out-of-plane bending. The results indicate that the FE models acknowledging the presence of the weld geometry and using solid elements are more suitable for the FEA of welded tubular joints and, moreover, the stress concentration factor (SCF) obtained at the chord “crown” location from the FE models subjected to the axial load case either approach, as in the case of the welded tubular T joint, or surpass, as in the case of the welded tubular X joint, the value estimated from the parametric equations as given in DNVGL-RP-C203.

A simulation approach for aircraft cargo loading considering weight and balance constraints

Air cargo transport is a growing industry in parallel with the growth in world trade and e-commerce. The global air cargo transport traffic getting busier, the importance of timely loading with minimum error is increasing. Therefore, digitalization of the air cargo loading process is needed. Assignment of Unit Load Devices (ULDs) to the specific positions on the freighter is performed by loadmasters by manual or semi-manual methods. This study aims to design a simulation model, which performs the ULD assignment automatically by simulating the loading process performed by the experienced loadmasters under the weight and balance constraints. The SEMMA (sample, explore, modify, model, assess) model is used while generating the simulation model. Fifty real-world loading orders were used to assess the performance of the model. The ULD assignment process by the simulation model and the loadmasters using semi-manual loading were compared with regard to time and center of gravity performance indicators. The results demonstrated that the simulation model can load all the given sets of ULDs, as efficiently as a loadmaster with a similar center of gravity in a shorter period of time. In conclusion, the proposed simulation model provides an efficient solution to the ULD assignment problem. However, the base model generated may be improved to address various real-world scenarios

To Solution of Contact Problem for Elastic Half-Strip

Contact problems for elastic stripes have been well studied and published in domestic scientific literature. This is partly due to the fact that normative documents on the foundation structure it is recommended to use this elastic foundation model for simulation of a “structure – foundation – soil foundation” system. Two variants of boundary conditions at the contact between a half-strip and a rigid non-deformable base are usually considered. The first boundary condition nullifies the vertical displacements and tangential stresses, the second one nullifies vertical and horizontal displacements. Contact problems for an elastic half-strip are much less investigated. The paper considers this contact problem when the first boundary condition for zeroing of vertical displacements and tangential stresses at the contact of a half-strip with a rigid, nondeformable base. When performing calculations in the traditional formulation without taking into account tangential stresses in the contact zone, the Zhemochkin method has been used, which reduces the solution of the contact problem of solid mechanics to the solution of a statically indeterminate problem by the mixed method of structural mechanics. Therefore, at first, we have found the displacements of the upper edge of the half-strip from the unit load uniformly distributed over the edge section. The resulting expression is used to compose a system of equations for the Zhemochkin method. The case of translational displacement of the die has been considered, and the graph of contact stress distribution under the die's sole has been given in the paper.