Box Structure Research Articles

Bank efficiency in Bangladesh revisited: a slack-based network DEA approach

PurposeData envelopment analysis (DEA) calculates the efficiency of a business unit if all the inputs are creating outputs within a “black box.” Under traditional DEA, the detailed process of that business unit is ignored. However, a network DEA can explain the black box structure and provide efficiency results for sub-sections within any business process. This study aims to propose a network DEA model that explains a bank's total operation.Design/methodology/approachEarlier studies have focused only on bank efficiency ignoring this breakdown. This study departs from them by using a slack-based two-stage network DEA under a novel banking business perspective.FindingsThe results reveal that network DEA provides better benchmarking insights than the traditional DEA. As such, better benchmarking can guide both the banking industry managers and policy makers in Bangladesh.Originality/valueThe major contribution of this study includes dividing a bank's total operation efficiency into two sub-operations: “core operations – collecting deposits and giving loans” and “additional operations – fees, commissions and other services.”

Product Parameter Calculation Based On Configurable Bom Model

In order to meet the customer ‘s demand for product customization and to solve the problem of complicated BOM configuration and product parameter calculation in manufacturing enterprises, we design a configurable BOM model and realize a dynamic calculation engine of product parameters based on the model. The configurable BOM model abstracts key entities such as product, product attribute, material, material attribute, material brand, and so on. It realizes flexible expansion of customized product and its materials. In order to get the key parameters of the product, such as raw material cost, sale price, etc., the key parameter’s expressions of the product are dynamically configured, the values of product attribute and material attribute are used as input parameters and the real-time dynamic calculation is realized by using the algorithm based on the JavaScript engine-Mozilla Rhino, which makes the parameter calculation logic decoupled from the business logic and achieves the scalability of the product parameter calculation. The validity of the configurable BOM model and the calculating engine of product parameters are illustrated by an example of BOM structure and raw material cost calculation of a flat box in carton manufacturing industry.

Bio-Nanocomposite Hydrogel Based on Zinc Alginate/Graphene Oxide: Morphology, Structural Conformation, Thermal Behavior/Degradation, and Dielectric Properties.

Bio-nanocomposite hydrogels based on sodium alginate (SA) as polymer matrix and graphene oxide (GO) nanosheets with zinc as crosslinking agent were synthesized with the aim of incorporating the intrinsic properties of their constituents (bioactivity and antimicrobial activity). Thus, stable and highly interconnected networks were obtained from GO nanosheets dispersed in SA matrices through interactions with low amounts of zinc. The GO nanosheets were successfully incorporated into the alginate matrix in the form of a complex nano-network involving different interactions: Bonds between alginate chains induced by Zn ions (egg box structure), interactions between GO nanosheets through Zn ions and hydrogen bonds between alginate chains, and GO nanosheets. The molecular interactions and morphology were confirmed by Fourier-transform infrared spectroscopy and transmission electron microscopy. The composite’s structural organization showed enhanced thermal stability. The glass transition temperature shifted to a higher temperature due to the reduced mobility induced by additional crosslinking bonds after incorporating the GO nanosheets and Zn into the polymer matrix. Finally, the dielectric behavior revealed that charge carrier mobility was hampered by the compact structure of the nanonetwork, which reduced conductivity. The combined properties of these nanocomposite hydrogels make them attractive biomaterials in the field of regenerative medicine and wound care since both surface bioactivity and antibacterial behavior are two critical factors involved in the success of a biomaterial.

IOT security analysis of BDT-SVM multi-classification algorithm

With the continuous development of the Internet of Things, the issue of IoT data security and privacy protection has received increasing attention. Compared with traditional Internet applications, IoT applications using smart terminals as supporting technologies have more complicated and serious security problems. This paper proposes a multi-classification algorithm based on double support vector machine decision tree. For all samples, the samples with the most separability were divided into two categories according to the size of the distinguishability between classes. In these two sub-categories, the most divisible samples are separately searched and divided into two categories, so that they can not be subdivided. This paper proposes a location privacy security protection mechanism based on anonymous tree and box structure, which provides location privacy protection for services oriented to intelligent terminals. The simulation results show that the common sub-collection of the anonymous group is larger, and the time overhead of building the group is smaller. At the same time, the BDT-SVM multi-classification algorithm can improve the accuracy of the intrusion detection system and reduce the detection time.

Analysis on the Influence of Assembly Gap on CFRP Assembly Stress Based on Finite Element Method

Due to the material properties and forming process of composite laminates, it is difficult to avoid smaller assembly gaps in the assembly process of laminates. In assembly process, liquid gaskets are generally used to compensate the smaller assembly gaps between laminates. Therefore, this paper established the equivalent assembly model of the laminated plate, and used the finite element analysis method to conduct numerical analysis and quantitative research on the mechanical influence of the assembly gap on the laminated plate assembly on the basis of analyzing the typical structure of the wing box. And the results of finite element method are compared with the experiment. This work provides a theoretical support to ensure the assembly quality of composite laminates.

Thermal Performance Analysis of Compact Heat Exchangers for Thermoelectric Generators

The efficiency of internal combustion engines (ICE) is usually about thirty percent of the total energy of the fuel. The residual energy is lost in the exhaust gas, the lubrication, and the cooling water in the radiators. Recently much of the researcher’s efforts have focused on taking advantage of wasted energy of the exhaust gas. Using a thermoelectric generator (TEG) is one of the promising ways. However, TEG depends entirely on the temperature difference, which may be offered by the exhaust muffler. An experimental test has been conducted to study the thermal performance of a different muffler internal design. The researchers resort to the use of lost energy in an ICE using TEG, which is one of the ways to take advantage of energy lost, which depends on the difference in temperature. TEG needs a heat exchanger and the muffler one of its types. In this work, four different types of mufflers will be designed and studied. The results showed that the thermal performances of the studied models compared to the empty cavity were as follows, the serial plate structure 56.11%, the central Box structure 52.73%, and the central curvature structure 29.61%. The highest thermal performance is on the serial plate structure relative to the other types.

A novel reliability sensitivity analysis method based on directional sampling and Monte Carlo simulation

Local reliability sensitivity and global reliability sensitivity are required in reliability-based design optimization, since they can provide rich information including variable importance ranking and gradient information. However, traditional Monte Carlo simulation is inefficient for engineering application. A novel numerical simulation method based on Monte Carlo simulation and directional sampling is proposed to simultaneously estimate local reliability sensitivity and global reliability sensitivity. By suitable transformation, local reliability sensitivity and global reliability sensitivity can be estimated simultaneously as by-products of reliability analysis for Monte Carlo simulation method. The key is how to efficiently classify Monte Carlo simulation samples into two categories: failure samples and safety samples. Directional sampling method, a classical reliability analysis method, is more efficient than Monte Carlo simulation for reliability analysis. A novel strategy based on nearest Euclidean distance is proposed to approximately screen out failure samples from Monte Carlo simulation samples using directional sampling samples. In the proposed method, local reliability sensitivity and global reliability sensitivity are by-products of reliability analysis using the directional sampling method. Different from existing methods, the proposed method does not introduce hypotheses and does not require additional gradient information. The advantages of the Monte Carlo simulation and directional sampling are well integrated in the proposed method. The accuracy and the efficiency of the proposed method for local reliability sensitivity and global reliability sensitivity are demonstrated by four numerical examples and two engineering examples including the headless rivet and the wing box structure.

Unique hollow-concave CoMoSx boxes with abundant mesoporous structure for high-performance hybrid supercapacitors

Unique hollow-concave CoMoSx boxes with abundant mesoporous structure are designed and constructed via a low-temperature calcination treatment followed by a hydrothermal process. Morphological observations show that the highly uniform and monodisperse hollow-concave CoMoSx boxes have an average size of approximately 410 nm. It is found that the hollow-concave structure of CoMoSx boxes can provide a large surface area and more active sites for the electrochemical reactions at the electrode/electrolyte interface, while reduce the volume of the inert inner cavities as well, achieving a maximum capacity of CoMoSx (784 C g−1 at a current density of 1 A g−1). Moreover, the distinctive hollow-concave structure can offer a buffer to accommodate the volume expansion/contraction of CoMoSx, thus leading to an excellent cycling stability. The CoMoSx//AC asymmetric supercapacitor device is assembled and delivers a maximum energy density of 36.9 Wh kg−1 at a power density of 0.8 kW kg−1.

Dimensional precision controlling on out-of-plane welding distortion of major structures in fabrication of ultra large container ship with 20000TEU

Ultra large container ship as an essential role during international trade, is required for precision fabrication due to highly efficient TEU loading and unloading. In this study, two major structures, so called watertight transverse bulkhead structure and torsion box structure of ultra large container with 20000TEU were examined for out-of-plane welding distortion prediction and mitigation with measurement and computational analysis. Based on the welding inherent deformation theory, typical welded joints of two major structures were systematically classified with the different material, thickness, welding condition and joining form; and the relationships between welding heat input and inherent deformations were also presented. Elastic FE analysis with shell elements model and welding inherent deformation as input loading was employed for welding distortion prediction. Not only the distributions but also the magnitudes of predicted out-of-plane welding distortions of considered major structures have a good agreement comparing to the measurements. Furthermore, welding sequence influence was considered for dimensional precision controlling during the watertight transverse bulkhead structure fabrication, and welding groove optimization of thick plate was examined for out-of-plane welding distortion mitigation during the torsion box structure fabrication. Computational results show that welding distortions of both ship block structures can be significantly reduced for requirement of fabrication precision.

Protecting Metadata of Access Indicator and Region of Interests for Image Files

With popularity of social network services, the security and privacy issues over shared contents receive many attentions. Besides, multimedia files have additional concerns of copyright violation or illegal usage to share over communication networks. For image file management, JPEG group develops new image file format to enhance security and privacy features. Adopting a box structure with different application markers, new standards for privacy and security provide a concept of replacement substituting a private part of the original image or metadata with an alternative public data. In this paper, we extend data protection features of new JPEG formats to remote access control as a metadata. By keeping location information of access control data as a metadata in image files, the image owner can allow or deny other’s data consumption regardless where the media file is. License issue also can be resolved by applying new access control schemes, and we present how new formats protect commercial image files against unauthorized accesses.

Optimization of 60Coγirradiation process for food

This study aims at improving the irradiation processing capability of the 60Coγ-radiation source and ensuring the quality of irradiated food.Thus,different stacking thicknesses and irradiation box structures were selected as process parameters,and the absorbed dose and unevenness of irradiated foods with different densities were measured and analyzed.The results showed that the spatial dose field distribution was symmetric with the center point of the source plate,symmetrically distributed above and below the center,and that the absorbed dose at the center was the highest.With increasing distance from the center,the absorbed dose decreased,and unevenness was observed.The greater the stacking thicknesses of products with the same density,the higher was the unevenness.There was no obvious effect of stacking thickness on low-density products.Combined with the dose distribution of the empty field,when the unevenness was greater than 1.4,the main contradiction was transformed into the influence of stacking thickness,mainly because of the inhomogeneity of the outer and central surfaces.At this time,in order to increase the utilization rate ofγ-rays,the minimum dose and loading amount should be determined for the product with a density of less than 0.36 g/cm3,consider thinning instead of tiling for the product with a density of more than 0.36 g/cm3.For products with a density of 0.3 g/cm3,the spatial distribution of the irradiation field at a height of 5 cm from the bottom of the irradiation box was better than that of the punch.In addition,theγ-ray utilization of the irradiation box height and punch increased by 8.26%and 8.30%,respectively,compared with those for the original irradiation box.Therefore,the loading capacity and the structure of the irradiation box can be considered to reduce the minimum absorbed dose of food,thereby improving the energy utilization rate and production efficiency ofγ-rays during food irradiation.

Improvement of Milling Stable Processing Condition for a Cutter With Large Ratio of Length to Diameter

In order to machine complex box and shell structures, the cutter with large ratio of length to diameter is usually used, whereas the low rigidity of the cutter hinders the increase of the stable machining parameters. This article develops one kind of damping cutter to improve the stable processing condition in this milling operation. The influences of modal characteristic of the cutter on chatter stability are investigated, where it is proven that increasing the dynamic stiffness can efficiently extend the stable zone. On this basis, two damping cutters are designed by inlaying the strips and damping core into the toolholder body. The influences of geometrical parameters and material property of the damping cutters on modal characteristics are theoretically analyzed, and the optimal geometrical dimensions are determined using the finite element simulation. Then, the two damping cutters are fabricated. After modal tests and milling machining experiments, the measured results validate the effectiveness of the developed damping cutters in terms of improvement of the stability frontier.

Research on the Development and Energy-saving of Assembling Box Buildings

Since the new era, the advancement of construction industrialization has been the focus of national attention. As an important part of the assembling building system, the box structure building has a high degree of industrialization, and has considerable development potential and industrial market. This paper first illustrates the development of box-structured buildings, and sorts out the background of box-structured buildings from foreign related theories and specific projects. Subsequently, the performance characteristics and deficiencies of box buildings in the specific construction under the current technical means are described. The paper also explores the energy efficiency of box buildings. Finally, the paper concludes with an outlook on the future development of box buildings.

Hardness and buckling strength of different material panels for a wing box structure with FE analysis

The wing box structure is made through different composite materials used in the aircraft industry due to enhanced properties. Buckling is an instability phenomenon that can in slender structures. Buckling in aircraft structures is undesirable as it alters the load path and hence the behavior of the structure and composition. Advanced wings are made up of thin-walled structures and the top skin is focused on compressive stress due to buckling volatility. This work describes finite element investigation on the buckling strength of the Al 2024T3, Glass Fiber-Reinforced Polymeric (GFRP), sandwich panels, and performance of hardness. The results showed that the sandwich panel produced a better critical load than other panels with less percentage of error. Obtained FE results matched with theoretical, but experimentally deviated slightly. Strain magnitude has increased with a small increment in load. Further, high hardness obtained in the sandwich material than others.

Real-time grain breakage sensing for rice combine harvesters using machine vision technology

Breakage rate is one of the most important indicators to evaluate the harvesting performance of a combine harvester. It is affected by operating parameters of a combine such as feeding rate, the peripheral speed of the threshing cylinder and concave clearance, and shows complex non-linear law. Real-time acquisition of the breakage rate is an effective way to find the correlation of them. In addition, real-time monitoring of the breakage rate can help the driver optimize and adjust the operating parameters of a combine harvester to avoid the breakage rate exceeding the standard. In this study, a real-time monitoring method for the grain breakage rate of the rice combine harvester based on machine vision was proposed. The structure of the sampling device was designed to obtain rice kernel images of high quality in the harvesting process. According to the working characteristics of the combine, the illumination and installation of the light source were optimized, and the lateral lighting system was constructed. A two-step method of “color training-verification” was applied to identify the whole and broken kernels. In the first step, the local threshold algorithm was used to get the edge of kernel particles in a few training images with binary transformation, extract the color spectrum of each particle in color-space HSL and output the recognition model file. The second step was to verify the recognition accuracy and the breakage rate monitoring accuracy through grabbing and processing images in the laboratory. The experiments of about 2300 particles showed that the recognition accuracy of 96% was attained, and the monitoring values of breakage rate and the true artificial monitoring values had good trend consistency. The monitoring device of grain breakage rate based on machine vision can provide technical supports for the intellectualization of combine harvester. Keywords: combine harvester, breakage rate monitoring, sampling box structure, machine vision, color classification DOI: 10.25165/j.ijabe.20201303.5478 Citation: Chen J, Lian Y, Zou R, Zhang S, Ning X B, Han M N. Real-time grain breakage sensing for rice combine harvesters using machine vision technology. Int J Agric & Biol Eng, 2020; 13(3): 194–199.

Study on the Seismic Performance of Box-Plate Steel Structure with Openings Modular Unit.

The box-plate steel structure residence is a box structure with stiffened steel plates directly used as load-bearing walls and floors. In practical engineering, due to the functional requirements of the building, it is necessary to open door or window openings on the box-plate steel structure walls. To study the seismic performance of the box-plate steel structure with openings system, two three-story single-compartment box-plate steel structures with openings modular units were designed and fabricated according to the 1:3 reduced scale. Through the quasi-static loading test, numerical simulation, and theoretical analysis, the failure process, failure mode, lateral force resistant capacity, and hysteresis performance of the specimens were studied. The impact of the different opening areas and opening position on the seismic performance of the box-plate steel structure was emphatically analyzed. The results of the test indicated that the openings on the steel wall plate would reduce the initial stiffness and the lateral force resistant capacity of the specimen; the destruction of the box-plate steel structure with openings modular unit under the low cyclic loading effect started with the tear in the corner of the openings and ended with the tear in the corner steel wall plate. Then, the finite element analysis (FEA) models were developed to supplement the experimental study, and the comparisons were made between measured and simulated results on load versus displacement relationships and failure modes. On the basis of the stressing mechanism of the box-plate structure modular unit, the calculation equation of the lateral force resistant capacity of the box-plate structure with openings modular unit was put forward. Then, the proved finite element analysis (FEA) models were used for parameter analysis of different influence parameters to verify the proposed calculation equation. The results showed that the proposed calculation equation had high accuracy and could be used as a design basis for practical engineering.

Influence of heat input on the microstructure and mechanical properties of CLAM steel multilayer butt-welded joints

Tungsten inert gas (TIG) welding was considered as one of the candidate technologies to achieve the box structure of test blanket module (TBM). In this paper, the effects of heat input on the microstructure and mechanical properties of multilayer TIG butt-welded China Low Activation Martensitic (CLAM) steel were investigated by microstructure observations, Vickers hardness, tensile and Charpy impact tests. The results showed that the microstructure of the weld metal (WM) were coarse quenched martensite and residual delta-ferrite. When the heat input value increased from 1.73 kJ/mm to 2.41 kJ/mm, the width of martensite laths increased slightly and the delta-ferrite content decreased firstly then increased. Moreover, the increasing heat input resulted in remarkable tempering effect on the previous layer of the WM by the following deposited layers. The transverse hardness distribution of the joints showed that softening occurred in the heat-affected zone (HAZ), and the hardness of WM decreased slightly as the heat input increased. The ultimate tensile strength values of the joints with various heat input were all higher than 630 MPa, and the rupture position located at the HAZ. Charpy impact toughness of the as-welded joints met the toughness criteria for the welded joint (≥27 J) of creep resistant 9Cr steel according to the standard of ISO-3580.

Stress analysis of arch foot of tie arch bridge based on spatial multi-scale model

For the arch foot connection structure of a steel box tied arch bridge in Guizhou Province, the spatial multi-scale finite element model is established by substructure method, and the influence line is loaded. The calculation results show that under the action of “dead load + live load”, the overall stress of arch foot is reasonable and the stress distribution is uniform, but the bearing roof, side web of arch foot and tied rod roof are complicated and the stress concentration is obvious. In the process of operation and maintenance, in order to ensure the safe use of bridges, we should focus on the observation of such components.

Hydroelastic analysis of a truss pontoon Mobile Offshore Base

Very Large Floating Structures (VLFS) are one among the solution to pursue an environmentally friendly and sustainable technology in birthing land from the sea. VLFS are extra-large in size and mostly extra-long in span. VLFS may be classified into two broad categories, namely the pontoon type and semi-submersible type. The pontoon-type VLFS is a flat box structure floating on the sea surface and suitable in regions with lower sea state. The semi-submersible VLFS has a deck raised above the sea level and supported by columns which are connected to submerged pontoons and are subjected to less wave forces. These structures are very flexible compared to other kinds of offshore structures, and its elastic deformations are more important than their rigid body motions. This paper presents hydroelastic analysis carried out on an innovative VLFS called truss pontoon Mobile Offshore Base (MOB) platform concept proposed by Srinivasan and Sundaravadivelu (2013). The truss pontoon MOB is modelled and hydroelastic analysis is carried out using HYDRAN-XR for regular 0 waves heading angle. Results are presented for variation of added mass and damping coefficients, diffraction and wave excitation forces, RAOs for translational, rotation and deformational modes and vertical displacement at salient sections with respect to wave periods.

Bionic Stiffener Layout Optimization with a Flexible Plate in Solar-Powered UAV Surface Structure Design

A cellular-based evolutionary topology optimization scheme over a small curvature big contour wing surface is proposed for the design of an ultralight surface structure. Using this method, a ground-structure technique is first applied to obtain homogeneous mesh generation with a predefined weight value over the design domain. Secondly, the stiffener path’s description is guided by a modified map L system topology method that simulates the growth of the bionic branch, and the structural components are obtained by the specified searching method according to weights of the previous mesh vertexes. Thirdly, an optimal curved stiffener layout is achieved using an agent-based algorithm to create individual instances of designs based on a small number of input parameters. These parameters can then be controlled by a genetic algorithm to optimize the final design according to goals like minimizing weight and structural weakness. A comparison is implemented for long-span panel stiffener layout generation between an initial straight case and a bionic optimal case via our method, thereby indicating the significant improvement of the buckling loads by steering the stiffener’s path. Finally, this bionic method is applied to the wing box structure design and achieves remarkable weight loss at last.