Superstructure Configuration Research Articles

Conceptual Design and Economic Optimization of Different Valorization Routes for Orange Peel Waste: The Application of the Biorefinery Concept for an Integral Use of Raw Material

Biorefineries are novel biotechnological routes designed to generate sustainable processes from renewable raw materials. The valorization of orange peel waste (OPW) provides high-value products based on their composition. The economic optimization of biorefineries through conceptual design and generation of superstructures based on the analysis of processing units is a topic of great interest. This work aimed to obtain the most profitable biorefinery through economic optimization strategies based on high-value-added products from OPW. Two stages were considered: The first stage consisted of the conceptual design of multiple OPW processing units (production of essential oil, mucic acid, phenolic compounds, biogas, among others). An OPW flow rate of 140 kg/h was selected as the base case. From the stand-alone units, a biorefinery superstructure (second stage) was designed. Finally, the units with the best mass and energy results were selected in order to maximize the net present value (NPV) and obtain an optimal biorefinery configuration. The results evidenced that the production of essential oil and biogas presented the best yields (2.61 mL and 0.028 m3 per kg OPW, respectively). This biorefinery configuration obtained an NPV of −7.7 mUSD from the base case. Through the evaluation of the different superstructure configurations, the combined production of essential oil, biogas, and mucic acid and a scale-up of over 22 times the base case generated the minimum processing scale. Under a Colombian context, the implementation of the biorefineries analyzed are promising since the minimum processing scale contemplated only 8.8% of the OPW production. Efforts to increase yields and decrease capital and operating expenses while keeping environmental impacts low should be pursued.

Optimizing the superstructure configuration of highway bridges for cost-effective construction

The structural progress of bridges in conjunction with efficiency has gained researchers’ attention in the last few decades. Structures optimization applying mathematical analysis is utilized to achieve sustainability in the design and construction of bridges. Despite the extensive research in this area of knowledge, further structural optimization development needs to be developed.The main goal of this research is to develop a decision support system (DSS) that selects the optimum superstructure configuration for highway bridges, considering financial and technical parameters. The most common structural systems in the longitudinal and transverse directions of bridges are considered in this research. Simple and continuous spans are included in the longitudinal direction, while open and closed sections for the transverse direction. Different construction materials are considered as well, like reinforced concrete, pre-stressed concrete, steel sections, and composite sections, to achieve a wide diversity of alternatives. The developed DSS was illustrated graphically as a map for the optimum superstructure configuration for certain span and span to depth ratio combinations. These different configurations obtained from the DSS were mapped three times. The first was based on direct cost only, the second on construction time only, and the third on the total cost of each alternative. Eventually, the DSS was verified using collected case studies and proposed a convenient selection of bridge superstructure configurations within the considered range of span dimensions.

Effects of Bi-doping on structure and properties of YBaCo2O5+δ layered perovskite cathode for intermediate-temperature solid oxide fuel cells

Layered perovskite oxides, Y1–xBixBaCo2O5+δ (YBBCx, x = 0.0–0.2) were investigated as cathodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs). XRD results indicate the YBBCx could be indexed to a tetragonal phase with trace of 3 × 3 × 1 superstructure configuration. No significant change in thermal expansion coefficients (TECs) was detected with the Bi-doping, and the TECs were 15.7–16.8 × 10−6 K−1 at 100–935 °C in air. Although the Bi-doping results in a decrease in conductivity of the YBBCx, the x = 0.2 sample still shows higher conductivity than that of a standard SOFC cathode (∼100 S cm−1). Additionally, the Bi-doping leads to an enhancement in the electrochemical performance mainly due to improved ion and electron charge transfers. Among the YBBCx compositions, the YBBC0.2 cathode shows the lowest polarization resistance (Rp) of 0.034 Ω cm2 at 700 °C. For a single cell with 300 µm thick La0.9Sr0.1Ga0.8Mg0.2O3–δ (LSGM) and YBBC0.2 cathode, a peak power density (Pmax) of 537 mW cm−2 at 700 °C was achieved with no significant deterioration in performance after a 100–h testing.

Design Optimization of PCI Girders: A Parametric Study

This study investigates the effect of superstructure configuration on the optimum design of slab on Precast I (PCI) girder bridges. For this purpose, more than 20,000 bridge cases of varying superstructure configurations are considered to investigate the effects of various superstructure parameters such as girder spacing, span length, slab thickness and girder types on the optimum design of slab on PCI girder bridges. PCI girders are designed conforming to the AASHTO LRFD for flexure using stress limits at the service limit state, then checked at ultimate for flexure and shear using factored loads at the strength limit state. A modified harmony search optimization algorithm is used to obtain optimum bridge design parameters using standard AASHTO PCI girders according to these AASHTO LRFD requirements. Those girders are designed taking into consideration geometrical constraints, stress constraints and constraints related to the conformity of the design with the AASHTO LRFD code. Various sensitivity analysis are performed to investigate the effect of different geometrical factors on the design of the girders, and easy-to-use design aids were developed. The outcomes of this study may facilitate the bridge engineers to choose optimum design parameters such as girder types and spacing as well as number strands for a certain span length before the design of slab on PCI girder bridges.

Modulation of Nano-superstructures and Their Optical Properties.

Self-assembly, which enables spontaneous arrangement of objects, is of particular importance for nanomaterials in both fundamental and applied research fields. Multiple types of nanoparticle superstructures have been successfully built in highly controllable and efficient manners through balancing the nanoscale interactions. Uniform and proper arrangement of nanoparticles inside the assembled superstructures is essential to exhibit their constant, reliable, and homogeneous functionalities. To be specific, the long-range ordered superlattices not only succeed with their building blocks' intrinsic property, but also, more importantly, can display collective properties that are absent both in individual nanoparticles and in their bulk states. One of the most attractive aspects of nanomaterials is their exceptional optical properties that have tremendous application potential in multidisciplinary fields. In this regard, constructing the superstructures from optical nano units like noble metal nanostructures, semiconductor nanoparticles, or hybrid nanomaterials is critical for attaining the unique optical properties and exploring their practical applications in multiple fields including photonics, optoelectronics, optical sensing, photocatalysis, etc. In this Account, we provide guidelines for self-assembly strategies to fabricate the superstructures and discuss the optical properties that the superstructures display. In the first part, we categorize and discuss the key factors that strongly affect the self-assembly process and determine the configurational and integral quality of the superstructures. On one hand, the diversity and designability of nanoparticles offer the intrinsic complexity of the building blocks, including geometry, size, composition, and surface ligand, which efficiently tailors the assembly process and superstructure configuration. On the other hand, multiple factors originating from the introduction of extrinsic features are recognized to facilitate the metastable or dynamic self-assembly process. Such extrinsic features include both matter like DNA origami, peptides, small molecules, etc. and nonmatter involved with electric fields, magnetic fields, light, temperature, etc. In the second part, we introduce the state-of the art progress on the collective optical performances of the assembled superstructures, including (1) chiral optics, such as circular dichroism and circularly polarized luminescence, (2) plasmonic properties and related applications, and (3) luminescence related optics and their applications. Finally, we summarize the existing problems and main challenges briefly, and some future directions of this field are proposed. We envision that, with deep understanding of the assembly mechanism and development of the synthetic and surface chemistry, rational modulation of nanoassemblies will be the trend of this field, which is beneficial to achieve the emerging collective performances and create new generation devices with advanced functions.

Design and Analysis of State Transport Utility Vehicle-Bus

Passenger transport is an inseparable ingredient of public transport system for developing and developed nations. In present work design and analysis of state transport utility vehicle ~ bus is carried out. Present paper focuses on the design enhancements in structural features of sub and superstructure without any alterations on the chassis provided by OEMs. Limiting dimensions of bus as prescribed by automotive industry standard and central motor vehicle rules are the design constraints accounted in the present work. This work was commenced with the thorough study of sub and superstructure configurations, seat locations, passenger load patterns, locations of doors, windows and emergency exits and other relevant bus attributes. Hand calculations for evaluation gross section modulus of chassis and cross member combination are presented. Usage of shear force and bending moment diagrams to evaluate the stress and deflection for the proposed load patterns is made before proceeding for finite element analysis. Finite element modelling and analysis of the sub and super structure combination is carried using shell elements with the presumption that chassis of the bus is rigid. Roll-over analysis of bus for the present configuration is presented.

Optimal transverse position for overweight trucks to cross simply supported multi-girder bridges

Recent years has witnessed a steady increase in the issued overweight vehicle permits. Damage and deterioration of bridges caused by overweight vehicles have received increasing attention. Most previous studies on overweight vehicles have focused on the routing and weight regulation of overweight trucks while little attention has been paid to the determination of the optimal transverse position for overweight trucks to cross highway bridges. This article aims to investigate the optimal transverse position for overweight trucks to cross the simply supported multi-girder bridges and provide suggestions for the management of overweight vehicles. Finite element analysis is performed for a group of prefabricated concrete bridges commonly used in China under the action of overweight trucks with varying transverse positions, and the optimal transverse position is determined based on the maximum bending stress of the girders. The effects of a few important factors, including the superstructure configuration, length of bridge spans, number of girders, type of girder connections, and support conditions, on the optimal transverse truck position are also investigated. The findings in this article highlight the importance of the transverse position of overweight trucks when crossing multi-girder bridges.

Seismic response of clay-pile-raft-superstructure systems subjected to far-field ground motions

A series of three-dimensional (3D) finite element analyses incorporated with a hyperbolic-hysteretic soil model were performed to investigate the seismic response of pile-raft-superstructure systems constructed on soft clay stratum, focusing on the seismic pile bending moment and superstructural responses. The seismic pile bending moment results suggested that using a lumped mass to represent the superstructure, which has been widely used in many other studies, could only perform well for a relatively low-rise superstructure; on the other hand, the seismic response of superstructure was found to be significantly affected by the soil-structure interaction, and both the detrimental and beneficial effects of dynamic soil-structure interaction were observed. Hence, coupled soil-foundation-superstructure analyses were primarily performed in this study. The influences of peak base acceleration, pile flexural rigidity and the configuration of superstructure on both the pile bending moment and superstructural responses were studied. Furthermore, some correlations were derived to relate the maximum pile bending moment to the influencing factors, which can be used as useful tools for obtaining preliminary and first-order estimates of the maximum pile bending moment for pile-raft-superstructure systems constructed on soft clay deposits.

Design and measurements of a tri‐band one‐dimensional electromagnetic bandgap resonator antenna

The authors utilise a one-dimensional (1D) stack of three identical unprinted dielectric slabs as a superstructure to design a novel yet simple tri-band electromagnetic bandgap resonator antenna (ERA). The design, inspired from classical single-band 1D ERAs, is conceived by creating two resonant defects in the superstructure configuration to make it suitable for tri-band and high gain operation. A prototype, fabricated using FR4 material, is tested with a waveguide-fed slot antenna at 10.3, 11.9 and 13.7 GHz with a frequency ratio of 1.33:1.16:1. The slot feeds the cavity simultaneously in the three frequency bands and provides good impedance matching in each frequency band. Peak measured gains of 14.3, 13.4 and 16.1 dBi and radiation efficiencies of 83, 85 and 85% are achieved in the lower, middle and higher frequency bands, respectively.

Solution strategies to the stochastic design of mineral flotation plants

The aim of this study is two-fold: first, to analyze the effect of stochastic uncertainty in the design of flotation circuits and second, to analyze different strategies for the solution of a two-stage stochastic problem applied to a copper flotation circuit. The paper begins by introducing a stochastic optimization problem whose aim is to find the best configuration of superstructure, equipment design and operational conditions, such as residence time and stream flows. Variability is considered in the copper price and ore grade. This variability is represented by scenarios with their respective probability of occurrence. The resulting optimization problem is a two-stage stochastic mixed integer nonlinear program (TS-MINLP), which can be extremely challenging to solve. For this reason, several solvers for this problem are compared and two stochastic programming methodologies are applied. The combination of these techniques allows the production of high quality solutions and an analysis of their sensitivity to epistemic uncertainty. The results show that the stochastic problem gives better designs because it allows operational parameters to adapt to the uncertainty of the parameters. The results also show that the flotation circuit structure can vary with the feed grade and copper price. The sensitivity analysis shows small to moderate variability with epistemically uncertain parameters.

공기저항 저감을 위한 컨테이너선 상부구조물 형상설계 및 성능평가

Reduction of the fuel oil consumption and corresponding greenhouse gas exhausted from ships is an important issue for today's ship design and shipping. Several concepts and devices on the superstructure of a container ship were suggested and tested in the wind tunnel to estimate the air drag reduction. As a preliminary performance evaluation, air drag contributions of each part of the superstructure and containers were estimated based on RANS simulation respectively. Air drag reduction efficiency of shape modification and add-on devices on the superstructure and containers was also estimated. Gap-protectors between containers and a visor in front of upper deck were found to be most effective for drag reduction. Wind tunnel tests had been carried out to confirm the drag reduction performance between the baseline(without any modification) configuration and two modified superstructure configurations which were designed and chosen based on the computation results. The test results with the modified configurations show considerable aerodynamic drag reduction, especially the gap-protectors between containers show the largest reduction for the wide range of heading angles. RANS computations for three configurations were performed and compared with the wind tunnel tests. Computation result shows the similar drag reduction trend with experiment for small heading angles. However, the computation result becomes less accurate as heading angle is increasing where the massively separated flow is spread over the leeward side.

Multicriteria optimization of a distributed energy supply system for an industrial area

In the paper a multi-objective optimization model for distributed energy supply systems optimization is presented. The superstructure of the system comprehends a district heating network that connects the users to each other, small-scale CHP systems, large centralized solar plant and a thermal storage. The optimization has to determine the optimal structure of the system, the size of each component inside the optimal solution and the optimal operation strategy. The multi-objective optimization is based on a MILP (Mixed Integer Linear Programming) model and takes into account as objective function a linear combination of the annual cost for owning, maintaining and operating the whole system and the CO2 emissions associated to the system operation. The model allows to obtain different optimal solutions by varying the relative weight of the economic and the environmental objectives. In this way the Pareto Front is identified and the possible improvements in both economic and environmental terms can be highlighted. The model has been applied to a specific case study and it has been optimized for different superstructure configurations and for two different values of the electricity carbon intensity. The obtained results show that the solar plant, coupled with the optimal thermal storage, allows reaching both environmental and economic goals.

Numerical study on the influence of superstructure configuration on coach rollover resistance performance

Coach rollover is one of the most dangerous accidents with respect to fatalities and injuries. The superstructure of a coach has an essential and vital impact on the rollover crashworthiness. To design the optimal superstructure of a coach requires that the effects of superstructure configuration on rollover crashworthiness are thoroughly understood. In order to find the design guidelines for superstructure configurations, this paper studied the influence of coach superstructure configuration on rollover resistance performance. A baseline finite element (FE) model of an intercity coach with semi-integral body is developed. Seven FE models are derived on the basis of the baseline model considering different superstructure configurations, such as closed rings, joints between the side-wall and floor, side window pillar structure as well as distances between the window rails and waistrail. Numerical simulations of rollover test are performed in accordance with the technical prescriptions in ECE Regulation 66. Performance indices, including residual space intrusion amount, energy absorption of each assembly, deformation mode and impact force are calculated and investigated. Results show that the closed rings, the joints between the side-wall and floor assembly as well as structural configurations of the side window pillars have significant effects on the rollover crashworthiness, but the rollover resistance is not sensitive to the distance between the window rail and waistrail. Design guidelines are proposed for coach superstructure to improve rollover crashworthiness based on comparative analysis on performance indices.

Optimum design of reverse osmosis systems for hydrogen peroxide ultrapurification

AbstractThis work is focused on the optimization of a reverse osmosis network proposed for the ultrapurification of chemicals, from technical grade to semiconductor grades demanded in electronic applications that require the use of high‐purity wet chemicals in the semiconductor manufacturing, as it is the case of hydrogen peroxide that is commonly used in the wafer cleaning and surface conditioning processes. An industrial installation able to produce simultaneously the five different Semiconductor Equipment and Materials International Grades of hydrogen peroxide is represented by a simplified superstructure configuration formulated as a nonlinear programming problem. The network integrates reverse osmosis membrane modules, mixers, and split functions, defined by the equations of mass balances and the Kedem–Katchalsky transport model for the description of the permeate flux and the metal rejection coefficients at each membrane stage. The objective of the design is to maximize the daily profit obtained from the sale of the electronic grades of hydrogen peroxide produced by the ultrapurification system. © 2012 American Institute of Chemical Engineers AIChE J, 2012

Parametric studies of exhaust smoke–superstructure interaction on a naval ship using CFD

The prediction of flow path of exhaust plume from the ship funnels is extremely complicated since the phenomenon is affected by a large number of parameters like wind velocity and direction, level of turbulence, geometry of the structures on ship’s deck, efflux velocity of smoke etc. To complicate the matters, the entire turbulent flow field is subject to abrupt changes as the yaw angle changes. In order to understand how the smoke is brought down to ship’s deck, it is necessary to have a knowledge of the funnel exhaust behavior very early in the design spiral of the ship by undertaking parametric investigation of the interaction effect between exhaust smoke and the ship superstructure. This paper presents such a parametric investigation on representative topside configurations of a generic frigate using computational fluid dynamics (CFD). The results presented have been analysed for a total of 112 different cases by varying velocity ratios and onset wind direction for four superstructure configurations. Use of both experimental and computational approaches has been made so that they become complementary to each other. The CFD simulation has been done using the computational code FLUENT version 6.0. Closure was achieved by using the standard k– ε turbulence model. The parametric study has demonstrated that CFD is a powerful tool to study the problem of exhaust smoke–superstructure interaction on ships and is capable of providing a means of visualising the path of the exhaust under different operating conditions very early in the design spiral of a ship.

Flow Visualization Studies of Exhaust Smoke-Superstructure Interaction on Naval Ships

The problem of ship funnel exhaust is often studied through flow visualisation using smoke in a wind tunnel. It is a very useful tool for the naval architect to ensure that the funnel exhaust will not interfere during operation. Naval ships are particularly prone to the problem of smoke nuisance because they tend to favor short funnel heights because of competition for topside space. This paper presents the flow visualization studies undertaken to understand the interaction between a bluff body air wake (of the funnel and superstructure/mast) and the ship's exhaust on naval ships. As a first step, the analysis of the exhaust smoke-superstructure interaction was carried out in a wind tunnel for a generic frigate shape. Four variants of the superstructure configuration with progressive introduction of the structures on the topside (i.e. the superstructure/mast upstream and downstream of the funnel) were investigated in the wind tunnel at two velocity ratios through flow visualization studies to understand their effect on the exhaust plume path. Apart from providing an insight into the process of plume dispersion in the vicinity of the funnel and other structures on topside of naval ships, the results of the flow visualization studies presented can also be used for validation of the computational fluid dynamics (CFD) simulations (including particle tracing) of the exhaust smoke-superstructure interaction for cruise vessels, ferries, yachts, as well as naval ships.

Three-dimensional FEM Analysis of Implant for Controlling Stress Concentration on Surrounding Bone.

In order to investigate the mechanical effects of the design of osseointegrated dental implant on the surrounding bone, the present study adopted more realistic approach by 3D FEM for stress analysis. An osseointegrated, screw type implant for molar region was selected, and the standard model and modified models in which the cusp inclination was increased to 40°, the abutment inclination was increased to 20° or the occlusal plane was buccolingually expanded were constructed. The results showed that the alteration of the configuration of superstructure, the occlusal contact positions or the occlusal relief variously changed the aspects of the stress distribution. However, any arrangement of these factors could not drastically relieve the stress concentration at the marginal crest of interfacial cortical bone so long as the occlusal contacts were limited to two points. An additional contact on the distal fossa to form three-point occlusal contacts could significantly reduce the maximum principal stresses and relieve the stress concentration.It was reconfirmed through the 3D FEM analyses that the proper design of superstructure, occlusal contour and balanced disposition of occlusal contacts would minimize the stress concentration on surrounding bone in centric occlusion, lateral sliding or mastication of foods and contribute to the good performance of implant restorations.

Stapedotomy in osteogenesis imperfecta patients.

Osteogenesis imperfecta (OI) is a connective tissue disorder characterized by osseous fragility, blue sclerae and hearing loss. In order to assess the impact of stapedotomy on improving hearing on OI, a retrospective, one-group, pre-test-post-test design was used to compare the pre-operative and post-operative audiograms of nine OI patients, treated with stapedotomy for their mixed hearing loss. Operative findings included fixation or thickening of the stapes footplate with normal superstructure configuration and hypervascularization of the promontory mucosa. Immediate post-operative results showed a significant improvement (p < 0.05) from 250-4000 Hz in air conduction and from 250-2000 Hz in bone conduction. A significant closure of the air-bone gap between 250-2000 Hz was also achieved (p < 0.05). The long-term results remained satisfactory with a mean threshold shift of 8 dB HL and an almost unchanged air-bone gap. These satisfactory results and the lack of complications make stapedotomy an appealing method for the management of OI-associated hearing loss.

The Detection of Course Change by Observing a Ship's Navigation Lights

Navigation lights for ships were first regulated in the United Kingdom by a statute introduced in 1848 and revised four years later, since when there have been few changes. Originally the regulations referred to oil-burning lamps fitted to vessels rarely in excess of 400 tons and rarely sailing much above 10 knots. The sheer increase in average size and in speed of typical modern ships, particularly marked over the last four decades, raises the question as to how effective the regulation lights actually are in practice. This question is made more pertinent in view of the other great change in ships, namely their general arrangement: the superstructure may be forward, midships or astern, masts and derricks vary in number, complexity and size. Although the regulations for the positioning of lights are reasonably comprehensive they inevitably leave considerable freedom to the designer because of the variety of superstructure configurations.

Determination theorique et domaines d’existence des differentes surstructures dans les composes A3+B1+X22− de type NaCl

In an ionic compound A 3+ B 1+ X 2 2− of NaCl type the six cations surrounding one anion can be arranged in two configurations which satisfy the Pauling's rule and this fact implies the following relation between nearest and next nearest neighbours short range order parameters: 4 α 1 + α 2 = −1 ( α i = 1–2 p AB.i , in which p AB.i is the probability of finding a B atom at the distance r i from an A atom). We show from this relation that the superstructure peaks in reciprocal space, for any superstructure configuration, are located upon a unique surface. To some peculiar points of this surface we can associate three types of long range ordered arrangements. These three types of superstructure are actually observed in ABX 2 compounds and for any of these the choice of the superstructure is determined by the ratio r 3+/ r 1+ between radii of A 3+ and B 1+. In the last part of this work, we therefore calculated the energy of the three possible configurations vs. ionic radii, intervening in Madelung energy through position parameters. We find in the r 3+/ r 1+ range, three zones with interchanges of the relative stabilities of the three structures. The agreement with experimental results is good provided that the anion polarization is taken into account. We also show that only few of these compounds can be dimorph.