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Phosphorous removal from wastewater by lanthanum modified Y zeolites

Weikang ZHANG, Ye TIAN

Frontiers of Chemical Science and Engineering 2015, Volume 9, Issue 2, Pages 209-215 doi: 10.1007/s11705-014-1448-4

Abstract: The adsorption capacities of Y zeolite and La (III)-modified Y zeolite were studied.A series of La(III)-modified Y zeolites with different La/Y zeolite mass ratios were characterized byThe capacity of the La (III)-modified Y zeolite to remove phosphate increased as the La/Y zeolite massratio increased and after 4 h, a phosphate removal efficiency of 95% was achieved for a La/Y zeolite

Keywords： phosphate removal wastewater lanthanum impregnation Y zeolites

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Anion-exchange membrane direct ethanol fuel cells: Status and perspective

Zhao, Y.S. Li, S.Y. Shen

Frontiers in Energy 2010, Volume 4, Issue 4, Pages 443-458 doi: 10.1007/s11708-010-0127-5

Abstract: Direct ethanol fuel cells (DEFCs) are a promising carbon-neutral and sustainable power source for portable, mobile, and stationary applications. However, conventional DEFCs that use acid proton-exchange membranes (typically Nafion type) and platinum-based catalysts exhibit low performance (i.e., the state-of-the-art peak power density is 79.5 mW/cm at 90°C). Anion-exchange membrane (AEM) DEFCs that use low-cost AEM and non-platinum catalysts have recently been demonstrated to yield a much better performance (i.e., the state-of-the-art peak power density is 160 mW/cm at 80°C). This paper provides a comprehensive review of past research on the development of AEM DEFCs, including the aspects of catalysts, AEMs, and single-cell design and performance. Current and future research challenges are identified along with potential strategies to overcome them.

Keywords： fuel cell direct ethanol fuel cells anion-exchange membrane ethanol oxidation reaction oxygen reduction reaction cell performance

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A pre-compensation method of the systematic contouring error for repetitive command paths

ZHANG,Y. H. CHEN,Y. P. CHEN

Frontiers of Mechanical Engineering 2015, Volume 10, Issue 4, Pages 367-372 doi: 10.1007/s11465-015-0367-5

Abstract:

For a repetitive command path, pre-compensating the contouring error by modifying the command path is practical. To obtain the pre-compensation value with better accuracy, this paper proposes the use of a back propagation neural network to extract the function of systematic contouring errors. Furthermore, by using the extracted function, the contouring error can be easily pre-compensated. The experiment results verify that the proposed compensation method can effectively reduce contouring errors.

Keywords： contouring error pre-compensation motion control system back propagation (BP) neural network

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Research on the valveless piezoelectric pump with Y-shape pipes

ZHANG Jianhui, LU Jizhuang, XIA Qixiao

Frontiers of Mechanical Engineering 2007, Volume 2, Issue 2, Pages 144-151 doi: 10.1007/s11465-007-0024-8

Abstract: A piezoelectric pump with its Y-shape elements is presented.Two Y-shape pipes are fixed outside the chamber serving as an inlet and outlet, with the chamber andEddies occurring in the Y-shape elements are smaller, which is beneficial for the transport of living

Keywords： chamber serving beneficial working frequency long-link correction

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Cracking evolution behaviors of lightweight materials based on

Y. Luo, S. C. Wu, Y. N. Hu, Y. N. Fu

Frontiers of Mechanical Engineering 2018, Volume 13, Issue 4, Pages 461-481 doi: 10.1007/s11465-018-0481-2

Abstract:

Damage accumulation and failure behaviors are crucial concerns during the design and service of a critical component, leading researchers and engineers to thoroughly identifying the crack evolution. Third-generation synchrotron radiation X-ray computed microtomography can be used to detect the inner damage evolution of a large-density material or component. This paper provides a brief review of studying the crack initiation and propagation inside lightweight materials with advanced synchrotron three-dimensional (3D) X-ray imaging, such as aluminum materials. Various damage modes under both static and dynamic loading are elucidated for pure aluminum, aluminum alloy matrix, aluminum alloy metal matrix composite, and aluminum alloy welded joint. For aluminum alloy matrix, metallurgical defects (porosity, void, inclusion, precipitate, etc.) or artificial defects (notch, scratch, pit, etc.) strongly affect the crack initiation and propagation. For aluminum alloy metal matrix composites, the fracture occurs either from the particle debonding or voids at the particle/matrix interface, and the void evolution is closely related with fatigued cycles. For the hybrid laser welded aluminum alloy, fatigue cracks usually initiate from gas pores located at the surface or sub-surface and gradually propagate to a quarter ellipse or a typical semi-ellipse profile.

Keywords： fatigue crack initiation and growth fatigue damage mechanism damage tolerance defect characterization laser welded aluminum alloys

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Biodiesel production from waste frying oil in sub- and supercritical methanol on a zeolite Y solid acid

Jorge MEDINA-VALTIERRA, Jorge RAMIREZ-ORTIZ

Frontiers of Chemical Science and Engineering 2013, Volume 7, Issue 4, Pages 401-407 doi: 10.1007/s11705-013-1354-1

Abstract: In this study biodiesel was produced from WFO in sub- and super-critical methanol on a zeolite Y solidThe transesterification of WFO with methanol around its critical temperature combined with a zeolite Y

Keywords： biodiesel methanol critical temperature waste frying oil zeolite Y

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Design and analysis of Salisbury screens and Jaumann absorbers for solar radiation absorption

Y. ZHAO, Hua BAO

Frontiers in Energy 2018, Volume 12, Issue 1, Pages 158-168 doi: 10.1007/s11708-018-0542-6

Abstract: Two types of resonance absorbers, i.e., Salisbury screens and Jaumann absorbers are systematically investigated in solar radiation absorption. Salisbury screen is a metal-dielectric-metal structure which overcomes the drawback of bulky thickness for solar spectrum. Such structures have a good spectral selective absorption property, which is also insensitive to incident angles and polarizations. To further broaden absorption bandwidth, more metal and dielectric films are taken in the structure to form Jaumann absorbers. To design optimized structural parameters, the admittance matching equations have been derived in this paper to give good initial structures, which are valuable for the following optimization. Moreover, the analysis of admittance loci has been conducted to directly show the effect of each layer on the spectral absorptivity, and then the effect of thin films is well understood. Since the fabrication of these layered absorbers is much easier than that of other nanostructured absorbers, Salisbury screen and Jaumann absorbers have a great potential in large-area applications.

Keywords： thin films admittance loci solar absorber

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Design concepts of an aircraft wing: composite and morphing airfoil with auxetic structures

P R BUDARAPU,Sudhir Sastry Y B,R NATARAJAN

Frontiers of Structural and Civil Engineering 2016, Volume 10, Issue 4, Pages 394-408 doi: 10.1007/s11709-016-0352-z

Abstract: This paper is categorized into two parts. (1) A frame work to design the aircraft wing structure and (2) analysis of a morphing airfoil with auxetic structure. The developed design frame work in the first part is used to arrive at the sizes of the various components of an aircraft wing structure. The strength based design is adopted, where the design loads are extracted from the aerodynamic loads. The aerodynamic loads acting on a wing structure are converted to equivalent distributed loads, which are further converted point loads to arrive at the shear forces, bending and twisting moments along the wing span. Based on the estimated shear forces, bending and twisting moments, the strength based design is employed to estimate the sizes of various sections of a composite wing structure. A three dimensional numerical model of the composite wing structure has been developed and analyzed for the extreme load conditions. Glass fiber reinforced plastic material is used in the numerical analysis. The estimated natural frequencies are observed to be in the acceptable limits. Furthermore, the discussed design principles in the first part are extended to the design of a morphing airfoil with auxetic structure. The advantages of the morphing airfoil with auxetic structure are (i) larger displacement with limited straining of the components and (ii) unique deformation characteristics, which produce a theoretical in-plane Poisson’s ratio of −1. Aluminum Alloy AL6061-T651 is considered in the design of all the structural elements. The compliance characteristics of the airfoil are investigated through a numerical model. The numerical results are observed to be in close agreement with the experimental results in the literature.

Keywords： wing design aerodynamic loads morphing airfoil auxetic structures negative Poisson’s ratio

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Surface hydrophobicity: effect of alkyl chain length and network homogeneity

Ramli, Jerry Y. Y. Heng

Frontiers of Chemical Science and Engineering 2021, Volume 15, Issue 1, Pages 90-98 doi: 10.1007/s11705-020-2003-0

Abstract: Understanding the nature of hydrophobicity has fundamental importance in environmental applications. Using spherical silica nanoparticles (diameter= 369±7 nm) as the model material, the current study investigates the relationship between the alkyl chain network and hydrophobicity. Two alkyl silanes with different chain length (triethoxymethylsilane (C1) vs. trimethoxy(octyl)silane (C8)) were utilised separately for the functionalisation of the nanoparticles. Water contact angle and inverse gas chromatography results show that the alkyl chain length is essential for controlling hydrophobicity, as the octyl-functionalised nanoparticles were highly hydrophobic (water contact angle= 150.6°±6.6°), whereas the methyl-functionalised nanoparticles were hydrophilic (i.e., water contact angle= 0°, similar to the pristine nanoparticles). The homogeneity of the octyl-chain network also has a significant effect on hydrophobicity, as the water contact angle was reduced significantly from 148.4°±3.5° to 30.5°±1.0° with a methyl-/octyl-silane mixture (ratio= 160:40 µL·g nanoparticles).

Keywords： hydrophobicity surface energy wettability alkyl chain network silica nanoparticle

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A perspective on the promoting effect of Ir and Au on Pd toward the ethanol oxidation reaction in alkaline media

Y. SHEN, Y. G. GUO, G. H. WEI, L. X. LUO, F. LI, J. L. ZHANG

Frontiers in Energy 2018, Volume 12, Issue 4, Pages 501-508 doi: 10.1007/s11708-018-0586-7

Abstract: There remain great challenges in developing highly efficient electrocatalysts with both high activity and good stability for the ethanol oxidation reaction in alkaline media. Herein, two architectures of tri-metallic PdIrAu/C electrocatalysts are designed and the promoting effect of Au and Ir on Pd toward the ethanol oxidation reaction (EOR) in alkaline media is investigated in detail. On the one hand, the tri-metallic Pd Au Ir/C electrocatalyst with a solid solution alloy architecture is less active relative to Pd Ir/C and Pd/C while the stabilizing effect of Au leads to both a higher activity and a lower degradation percentage after 3000 cycles of the accelerated degradation test (ADT) on Pd Au Ir/C than those on Pd Ir/C. On the other hand, the tri-metallic Pd Ir@(1/3Au)/C electrocatalyst with a near surface alloy architecture delivers a much higher activity with an improvement up to 50.4% compared to Pd Ir/C. It is speculated that for the tri-metallic Pd Ir@(1/3Au)/C electrocatalyst, certain Au atoms are well designed on surfaces to introduce an electronic modification, thus leading to an anti-poisoning effect and improving the EOR activity.

Keywords： fuel cells catalysts ethanol oxidation alkaline media solid solution alloy near surface alloy

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Enrichment of CO from syngas with Cu(I)Y adsorbent by five-bed VPSA

Shuna LI, Huawei YANG, Donghui ZHANG

Frontiers of Chemical Science and Engineering 2013, Volume 7, Issue 4, Pages 472-481 doi: 10.1007/s11705-013-1351-4

Abstract: Cu(I)Y adsorbent was prepared by reduction of Cu(II)Y which was prepared by ion exchange between theThe dynamic adsorption capacity of Cu(I)Y for CO was calculated by adsorption breakthrough curve measured

Keywords： Cu(I)Y adsorbent breakthrough curve desorption VPSA simulation

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Lessons learned from developing and implementing refinery production scheduling technologies

Marcel JOLY, Mario Y. MIYAKE

Frontiers of Engineering Management 2017, Volume 4, Issue 3, Pages 325-337 doi: 10.15302/J-FEM-2017033

Abstract: An increasing number of novel and highly specialized computer-aided decision-making technologies for short-term production scheduling in oil refineries has emerged and evolved over the past two decades, thereby encouraging refiners to permanently rethink the way the refining business is operated and managed. In this report, we discuss the key lessons learned from one of the pioneering, yet daring, enterprise-wide programs entirely implemented in an energy company devoted to developing and implementing an advanced refinery production scheduling (RPS) technology, i.e., the RPS system of Petrobras. Apart from mathematical and information technology issues, the long-term sustainability of a successful RPS project is, we argue, the outcome of a virtuous cycle grounded on permanent actions devoted to improving technical education inside the organization, reinspecting organizational cultures and operational paradigms, and developing working processes.

Keywords： automation decision making oil refinery optimization production scheduling

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Modeling of semi-rigid beam-to-column steel joints under extreme loading

C FANG, B A IZZUDDIN, A Y ELGHAZOULI, D A NETHERCOT

Frontiers of Structural and Civil Engineering 2013, Volume 7, Issue 3, Pages 245-263 doi: 10.1007/s11709-013-0215-9

Abstract: Joints play an important role in providing ductility for steel-composite structures subject to extreme loading conditions, such as blast, fire and impact. Due to sound energy dissipation capability and fabrication efficiency, semi-rigid joints have increasingly received attention during the last decade. This paper presents a component approach for modeling semi-rigid beam-to-column joints based on Eurocode3, where the post-elastic response, including component strain hardening and ultimate rotational capacity, is also considered. Failure criteria are defined based on the ultimate deformation capacity of components and bolt-rows. The model enables a direct integration of joint response into global frame models with the consideration of axial deformability, such that the interaction between bending moment and axial force within the joints can be realistically captured. In addition, elevated temperature can be considered in the joint model via the degradation of the component response. Through comparisons with available test data, the joint model is shown to have good accuracy, and the failure criteria are found to be reliable yet conservative. The strain hardening response of components is shown to have significant influence on the ultimate bending capacity of the joints, while neglecting it usually leads to a conservative prediction.

Keywords： semi-rigid joint component method ductility elevated temperature

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Valveless pumping using a two-stage impedance pump

LEE, Y. A. ABAKR, K.-C. WOO

Frontiers of Mechanical Engineering 2013, Volume 8, Issue 3, Pages 311-318 doi: 10.1007/s11465-013-0270-x

Abstract:

Impedance pump is defined as a type of valveless pumping mechanism, where an elastic tube is joined with a tube of different impedance, a periodic asymmetrical compression on part of the elastic tube will produce a unidirectional flow. Numerical and experimental studies had been conducted in the past, but little experimental work was found to exploit the principle of multi-stage impedance pumping for fluid transportation. This paper concentrates on the fluid behavior for an open-loop two-stage system experimentally. The aim of this work is to have an insight on the deliverable head and pumping rate of an open-loop two-stage impedance pumping system. This paper generally investigates the effect of different parameters towards the generation of unidirectional flows and composite flow of two opposite directions. Results obtained are of significant values.

Keywords： valveless pumping open-loop two-stage unidirectional composite

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Performance assessment of innovative seismic resilient steel knee braced frame

Y. YANG,Yuanjie LI

Frontiers of Structural and Civil Engineering 2016, Volume 10, Issue 3, Pages 291-302 doi: 10.1007/s11709-016-0340-3

Abstract: Buckling restrained knee braced truss moment frame (BRKBTMF) is a novel and innovative steel structural system that utilizes the advantages of long-span trusses and dedicated structural fuses for seismic applications. Steel trusses are very economical and effective in spanning large distance. However, conventional steel trusses are typically not suitable for seismic application, due to its lack of ductility and poor energy dissipation capacity. BRKBTMF utilizes buckling restrained braces (BRBs) as the designated structural fuses to dissipate the sudden surge of earthquake energy. This allows the BRKBTMF to economically and efficiently create large span structural systems for seismic applications. In this paper, a prototype BRKBTMF office building located in Berkeley, California, USA, was designed using performance-based plastic design procedure. The seismic performance of the prototype building was assessed using the state-of-the-art finite element software, OpenSees. Detailed BRB hysteresis and advanced element removal technique was implemented. The modeling approach allows the simulation for the force-deformation response of the BRB and the force redistribution within the system after the BRBs fracture. The developed finite element model was analyzed using incremental dynamic analysis approach to quantify the seismic performance of BRKBTMF. The results show BRKBTMF has excellent seismic performance with well controlled structural responses and resistance against collapse. In addition, life cycle repair cost of BRKBTMF was assessed using the next-generation performance-based earthquake engineering framework. The results confirm that BRKBTMF can effectively control the structural and non-structural component damages and minimize the repair costs of the structure under different ranges of earthquake shaking intensities. This studies conclude that BRKBTMF is a viable and effective seismic force resisting system.

Keywords： buckling restrained brace innovative structural system collapse simulation seismic assessment