Huang S.-M.,Dongguan University of Technology
Applied Thermal Engineering | Year: 2017
Heat and mass transfer in a cross-flow hollow fiber membrane absorption heat pump (HFMAHP) employed for heating are investigated. The HFMAHP is a membrane contactor formed by rows of hollow fiber membranes arranged in a cross-flow arrangement with a series of air-gaps between the neighboring rows. In the HFMAHP, the refrigerant (water) and the absorbent (salt solution) streams are separated by the semi-permeable composite membranes, which only allow the permeation of water vapor. The solution stream attracts the water vapor from the water stream across the membranes and the air-gaps. The solution temperature increases because of the latent and mixing heats released on the solution side. A mathematical model of the coupled heat and mass transfer in the HFMAHP is established by converting it to a parallel-plate one. A finite difference approach is employed to solve the equations governing the momentum, coupled heat and mass transports. The pressure drop and solution temperature lift are calculated and experimentally validated. It can be found that the packing fraction and the fiber outer diameter are optimized to be 0.48 and 1.2 mm, respectively. The solution temperature lift, the overall heat and mass transfer coefficients increase with the skin layer thickness increasing. The skin layer has a more-determining effect than that for the porous layer. © 2016 Elsevier Ltd
Jian R.-Q.,Dongguan University of Technology
Letters in Mathematical Physics | Year: 2017
In this short note, we construct quasi-idempotent Rota–Baxter operators by quasi-idempotent elements and show that every finite dimensional Hopf algebra admits nontrivial Rota–Baxter algebra structures and tridendriform algebra structures. Several concrete examples are provided, including finite quantum groups and Iwahori–Hecke algebras. © 2016, Springer Science+Business Media Dordrecht.
Li R.,Dongguan University of Technology |
Liu A.X.,Dongguan University of Technology
Proceedings - International Conference on Data Engineering | Year: 2017
This paper concerns the fundamental problem of processing conjunctive queries that contain both keyword conditions and range conditions on public clouds in a privacy preserving manner. No prior Searchable Symmetric Encryption (SSE) based privacy-preserving conjunctive query processing scheme satisfies the three requirements of adaptive security, efficient query processing, and scalable index size. In this paper, we propose the first privacy preserving conjunctive query processing scheme that satisfies the above requirements. To achieve adaptive security, we propose an Indistinguishable Bloom Filter (IBF) data structure for indexing. To achieve efficient query processing and structure indistinguishability, we propose a highly balanced binary tree data structure called Indistinguishable Binary Tree (IBtree). To optimize searching efficiency, we propose a traversal width minimization algorithm and a traversal depth minimization algorithm. To achieve scalable and compact index size, we propose an IBtree space compression algorithm to remove redundant information in IBFs. We formally prove that our scheme is adaptive secure using a random oracle model. The key contribution of this paper is on achieving conjunctive query processing with both strong privacy guarantee and practical efficiency in terms of both speed and space. We implemented our scheme in C++, evaluated and compared its performance with KRB  for keyword queries and PBtree  for range queries on two realworld data sets. Experimental results show that our scheme is fast and scalable (in milliseconds). © 2017 IEEE.
Huang S.-M.,Dongguan University of Technology
International Journal of Thermal Sciences | Year: 2016
Membrane channels have been extensively used for air humidity control and energy recovery. The membranes are commonly parallel-plate type. However they probably are deformed because of their weak mechanical strengths and fluid pressure. Effects of the deformation heights (Δh) on the laminar flow and heat transfer in the plate membrane channels are studied based on two unit cells. Each one of them includes two neighboring membranes and a channel sandwiched by the membranes. The equations governing the momentum and heat transports are established together with a uniform wall temperature boundary condition and numerically solved by a finite volume approach. The mean (fRe) and Nusselt number (Num) are obtained. The influences of the deformation heights (Δh), aspect ratios (b/a), and Reynolds numbers (Re) on the (fRe)m and Num are calculated. It can be found that when the b/a is less than or equal to 25, the Num rises with the Δh increasing for the air channel. However the Num firstly rises, and then decreases with the Δh increasing when the b/a ranging from 30 to 40. For the water/LiCl solution channels, the Num for the LiCl solution is about 40%-56% larger than that for the water stream. © 2016 Elsevier Masson SAS. All rights reserved.
Wang C.,Dongguan University of Technology
Journal of Convergence Information Technology | Year: 2012
In this paper, study on learning mechanism of industrial clusters under information environment is proposed. Cluster learning mode analysis can be discussed from the knowledge complexity and structure of clusters. Firstly, With the development of knowledge complexity, the importance of innovation based on scientific research or discovery-driven innovation improve gradually. Secondly, assembling clusters and complex product clusters are dominated by vertical relationships and learning models among clusters, traditional clusters and high-tech clusters are relatively balanced between horizontal learning interaction mechanisms and vertical learning interaction mechanism. On this basis, this paper discusses learning mechanisms and governance of four types of industrial clusters.
Wang H.,Dongguan University of Technology |
Peng X.,Dongguan University of Technology
Journal of the Optical Society of America B: Optical Physics | Year: 2012
We present an optical steering method in optical lattice with Kerr nonlinearity based on spatial phase modulation. By choosing proper phase modulation parameters, we can easily realize optical deflection, optical switching, and splitting of optical beams. The effect of lattice depth and lattice period on the optical steering is also discussed in detail. © 2012 Optical Society of America.
Liu Q.,Dongguan University of Technology
Journal of Global Optimization | Year: 2013
In this paper, we discuss the performance of the DIRECT global optimization algorithm on problems with linear scaling. We show with computations that the performance of DIRECT can be affected by linear scaling of the objective function. We also provide a theoretical result which shows that DIRECT does not perform well when the absolute value of the objective function is large enough. Then we present DIRECT-a, a modification of DIRECT, to eliminate the sensitivity to linear scaling of the objective function. We prove theoretically that linear scaling of the objective function does not affect the performance of DIRECT-a. Similarly, we prove that some modifications of DIRECT are also unaffected by linear scaling of the objective function, while the original DIRECT algorithm is sensitive to linear scaling. Numerical results in this paper show that DIRECT-a is more robust than the original DIRECT algorithm, which support the theoretical results. Numerical results also show that careful choices of the parameter ε can help DIRECT perform well when the objective function is poorly linearly scaled. © 2012 Springer Science+Business Media, LLC.
Huang S.-M.,Dongguan University of Technology |
Yang M.,Dongguan University of Technology
Applied Energy | Year: 2013
The longitudinal fluid flow and heat transfer between an elliptical hollow fiber membrane tube bank (EHFMTB) used for air humidification are investigated. In the tube bank, the water stream flows inside the fibers, while the air stream flows axially between the fibers. The air and the water streams, in a counter flow arrangement, are exchanging heat and moisture effectively through the membranes. Two regularly populated arrangements of the tube bank, in-line and staggered, are considered. Two representative unit cells consisting of two fibers and the air stream flowing longitudinally between the fibers are selected as the calculation domains. The governing equations for the fluid flow and the heat transfer between the EHFMTB are established and numerically solved via a boundary-fitted coordinate transformation method. The friction factor and Nusselt number in the unit cells are then obtained, analyzed, and experimentally validated. They are compared with the data obtained for a hollow fiber membrane tube bank (HFMTB). The results are useful for structural optimization and performance evaluations of the EHFMTB employed for air humidification. © 2013 Elsevier Ltd.
Jian R.-Q.,Dongguan University of Technology
Letters in Mathematical Physics | Year: 2013
In this letter, we use quantum quasi-shuffle algebras to construct Rota-Baxter algebras, as well as tridendriform algebras. We also propose the notion of braided Rota-Baxter algebras, the relevant object of Rota-Baxter algebras in a braided tensor category. Examples of such new algebras are provided using quantum multi-brace algebras in a category of Yetter-Drinfeld modules. © 2013 Springer Science+Business Media Dordrecht.
Dongguan University of Technology | Date: 2014-11-05
A non-circular rebar used in concrete includes a square rebar, a rectangular rebar, an elliptical rebar, a trapezium rebar, a triangular rebar, and a rebar with round edges and corners. The square, rectangular, elliptical, trapezium, and triangular rebars and the rebar with round edges and corners substitute the conventional circular rebar, so that the rebars can be tied easily to save the space occupied. Since the distance of the resultant force of the tensile stresses of the rebar from the boundary of the concrete becomes smaller or the concrete protecting layer becomes thicker, the change of the shape increases the bonding between the rebar and concrete, and the safety of construction is improved. The non-circular rebar includes a smooth rebar and a ribbed rebar with a non-circular main cross-section.