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In this article, experimental and finite element (FE) numerical investigations on interior wide-beam column joints are presented. The experimental research consisting of three full-scale interior wide-beam column specimens was car...
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In this article, experimental and finite element (FE) numerical investigations on interior wide-beam column joints are presented. The experimental research consisting of three full-scale interior wide-beam column specimens was carried out at Nanyang Technological University, Singapore to study the seismic behavior. Details of the test results are discussed to understand the specimens' seismic-performance in terms of general behavior, hysteresis loops response, and strain profiles of longitudinal reinforcement. In the FE numerical study, the three-dimensional (3D) model developed is validated by comparing the analysis results with the experimental test results, which has shown a good agreement. A parametric study is performed to elucidate more information and to understand the influence of critical parameters affecting the joint behavior such as column axial load, beam anchorage ratio, and wide beam participation.
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This article presents the analytical and experimental investigations carried out on reinforced concrete (RC) columns with light transverse reinforcement. A semi-empirical model is developed to estimate the ultimate displacement (d...
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This article presents the analytical and experimental investigations carried out on reinforced concrete (RC) columns with light transverse reinforcement. A semi-empirical model is developed to estimate the ultimate displacement (displacement at axial failure) of'RC columns with light transverse reinforcement subjected to simulated seismic loading. The developed model is calibrated using the collected data of RC columns tested to the point of axial failure. A series of experiments is conducted on five RC columns with light transverse reinforcement to validate the applicability and accuracy of the developed model. It is concluded from the study that the mean ratios of the experimental to predicted ultimate displacement and its coefficient of variation are 1.077 and 0.194, respectively, showing a good correlation between the developed model and the experimental data.
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In spite of advances in various transformation systems the transformation of a nonmonotonic-logic-based requirements specification into a procedural (imperative) language program has not been investigated. This paper presents a lo...
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In spite of advances in various transformation systems the transformation of a nonmonotonic-logic-based requirements specification into a procedural (imperative) language program has not been investigated. This paper presents a logic-based transformation system that can transform a nonmonotonic-logic-based specification, the Frame-and-Rule Oriented Requirement Specification Language (FRORL), into procedural language programs. We discuss how to handle nonmonotonic inheritance in FRORL and then establish a matrix-based data flow and dependency analysis mechanism to find all the possible data transformation paths in a logic-based specification. Using a newly developed algorithm, we can adjust the execution sequence of a logic-based specification so that the functions included in the logic-based specification can be represented by a sequential procedural language program.
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In Fiber-Wireless (FiWi) access network, the optical back-end is vulnerable to the network component failure due to its tree topology. Any failure at the optical back-end may cause huge data loss. Thus, the survivability in FiWi i...
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In Fiber-Wireless (FiWi) access network, the optical back-end is vulnerable to the network component failure due to its tree topology. Any failure at the optical back-end may cause huge data loss. Thus, the survivability in FiWi is an important issue, especially the protection for the optical back-end. Some works propose to protect the optical back-end in FiWi by means of the wireless rerouting in the wireless front-end. However, these works cannot guarantee that there are always the available wireless paths for the traffic rerouting. In this paper, we divide the failures at the optical back-end into ONU-level failure and OLT-level failure according to the failure severity. To tolerate the ONU-level failure, we allocate each ONU a partner ONU and establish the wireless-backup-path between them by deploying backup radios on the traversed wireless routers. To tolerate the OLT-level failure, we cluster all segments in the network and place the backup fibers among the segments in each cluster to establish the protection ring. Thus, each pair of segments in the same cluster can backup for each other along the optical-backup-paths on the protection ring. We propose the heuristic algorithms to minimize the cost of backup radios and the cost of backup fibers. The simulation results demonstrate that the proposed algorithms are effective in enhancing the survivability of FiWi, while requiring less cost than the previous works.
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Both maximum displacement and displacement ductility factors should be considered in the design of a blast-resistant structure since both parameters correlate with an expected performance level of a reinforced concrete (RC) struct...
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Both maximum displacement and displacement ductility factors should be considered in the design of a blast-resistant structure since both parameters correlate with an expected performance level of a reinforced concrete (RC) structural member during a blast event. The blast-resistant design procedure discussed in this paper takes into account both the maximum displacement and displacement ductility responses of an equivalent single-degree-of-freedom (SDOF) system, while the response of the SDOF system is made equivalent to the corresponding targets of design performance. Some approximate errors are present when comparing the actual responses of the structural member, which has been designed for blast loading, and their corresponding design performance targets. Two indices are defined to quantify the approximation errors, and their expressions are obtained through comprehensive numerical and statistical analyses. By using the error indices, the design procedure is then modified such that the approximate responses of the RC member are equivalent to the targets of the design performance. The modified procedure is implemented in three design examples and numerically evaluated. It is concluded that the modified procedure can be used more effectively in order to ensure that the actual responses of designed members reflect the respective targets of design performance.
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Homogeneous N-glycoproteins carrying defined natural N-glycans are essential for detailed structural and functional studies. The transglycosylation activity of the endo-β-N-acetylglucosaminidases from Arthrobacter protophormiae (...
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Homogeneous N-glycoproteins carrying defined natural N-glycans are essential for detailed structural and functional studies. The transglycosylation activity of the endo-β-N-acetylglucosaminidases from Arthrobacter protophormiae (Endo-A) and Mucor hiemalis (Endo-M) holds great potential for glycoprotein synthesis, but the wild-type enzymes are not practical for making glycoproteins carrying native N-glycans because of their predominant activity for product hydrolysis. In this article, we report studies of two endoglycosidase-based glycosynthases, EndoM-N175A and EndoA-N171A, and their usefulness in constructing homogeneous N-glycoproteins carrying natural N-glycans. The oligosaccharide oxazoline corresponding to the biantennary complex-type N-glycan was synthesized and tested with the two glycosynthases. The EndoM-N175A mutant was able to efficiently transfer the complex-type glycan oxazoline to a GlcNAc peptide and GlcNAc-containing ribonuclease to form the corresponding homogeneous glycopeptide/glycoprotein. The EndoA-N171 A mutant did not recognize the complex-type N-glycan oxazoline but could efficiently use the high-mannose-type glycan oxazoline for transglycosylation. These mutants possess the transglycosylation activity but lack the hydrolytic activity toward the product. Kinetic studies revealed that the dramatically enhanced synthetic efficiency of the EndoA-N171A mutant was due to the significantly reduced hydrolytic activity toward both the Man_9GlcNAc oxazoline and the product as well as to its enhanced activity for transglycosylation. Thus, the two mutants described here represent the first endoglycosidase-based glycosynthases enabling a highly efficient synthesis of homogeneous natural N-glycoproteins.
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Power ultrasound has proved to be very useful in controlling crystallisation processes since sonication can enhance both the nucleation rate and crystal growth rate by producing fresh and/or more nucleation sites. Therefore, in th...
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Power ultrasound has proved to be very useful in controlling crystallisation processes since sonication can enhance both the nucleation rate and crystal growth rate by producing fresh and/or more nucleation sites. Therefore, in this study, power ultrasound was applied to assist the freezing process. The results showed that the freezing rate of potato sample was improved with the application of ultrasound, compared to that without ultrasound. Higher output power and longer exposure time to ultrasound would help to enhance the freezing rate. However, the heat produced when ultrasound passes through the medium limited the power applied and the exposure time. In this work, the freezing rate was fastest with an output power of 15.85 W and a treatment time of 2 min. The analyses conducted on the microstructure of potato tissue using cryo-scanning electron microscopy technique showed that the plant tissue exhibited a better cellular structure under ultrasonic power of 15.85 W. Much less intercellular void and cell disruption was observed. This was attributed to high freezing rate obtained under high ultrasonic level and thus the domination of intracellular small ice crystals.
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An innovative physical method to control fouling in heat transfer equipment-low voltage electrolysis anti-fouling (LVEAF) technology-is introduced. The objective of the present study is to testify the effect of LVEAF treatment in ...
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An innovative physical method to control fouling in heat transfer equipment-low voltage electrolysis anti-fouling (LVEAF) technology-is introduced. The objective of the present study is to testify the effect of LVEAF treatment in forced convective system and identify the operating mechanism. A series of fouling tests were carried out with and without LVEAF treatment. During the experiments fouling resistance was monitored, and the properties of test liquid were measured, including hardness, alkalinity, electrical conductivity, and pH. The main results were as follows: (1) The fouling was effectively restrained to form on the heat exchanger surface if the circulating water was treated with LVEAF. The scale inhibition ratios exceeded 90% in most cases. (2) The LVEAF technology is an active anti-fouling technology with lower energy consumption. The properties of treated test liquid were changed. (3) Electrochemical reactions occur near the electrode due to the low current existence in the water when the LVEAF device is working. A lot of fouling deposits formed in the test liquid near the cathode or on the inner surface of the treatment unit, but did not deposit on the heat exchanger surface.
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Purpose - The purpose of this paper is to present a method for ultrasonically molding polymer powder in a micro plastic part mold. In the method, a printed circuit board (PCB) in which micro-hole arrays are drilled is used as a mi...
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Purpose - The purpose of this paper is to present a method for ultrasonically molding polymer powder in a micro plastic part mold. In the method, a printed circuit board (PCB) in which micro-hole arrays are drilled is used as a micro cavity insert. With the utilization of ultrasonic vibration, the polymer powder, which is prefilled and compacted in a micro cavity, mutually generates great sliding friction heat so as to be rapidly plasticized and molded. Design/methodology/approach - Micro carbide drill bits of which the diameters are 100.0 /am, 150.0 /am and 200.0 /am, respectively, are used for drilling the PCB to form a micro-hole array insert. Next, two kinds of various ultra-high molecule weight polyethylene (UHMW-PE) powder with various grain diameters are directly filled into a charging barrel and a mold cavity with the micro-hole array insert. Proper process parameters are set on ultrasonic plasticizing and molding equipment so that a molding test can be performed. The melt of UHMW-PE can be rapidly filled into the cavity. Finally, micro-column array plastic parts are successfully prepared. Findings - The micro-hole array PCB is a mold insert which is quite applicable for the ultrasonic molding of the powder in the mold. When a molding material is the coarse UHMW-PE powder with the grain diameter of about 350/am, the diameter replication rates of the micro-column array plastic parts become good in order with the increased micro-hole diameter of the PCB. When the fine UHMW-PE powder with the grain diameter of about 80 /am is adopted, the diameter replication rates of the micro-column array plastic parts become good in order with the decreased micro-hole diameter of the PCB. Originality/value - In this paper, the micro-column array plastic parts with good replicability are successfully prepared by a technique for ultrasonically plasticizing and molding in the cavity. The technique can be applied to the fields of medical treatment, communication, optics, chemistry and so on, such as biological micro needle arrays, micro biological chips, optical memories, and micro chemical reaction chips.
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Selection of metal matrix of Gr_f/Al composites is very important to improve properties of composites. M40 carbon fiber-reinforced aluminum composites (Gr_f/Al) with different matrix were fabricated by a pressure infiltration meth...
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Selection of metal matrix of Gr_f/Al composites is very important to improve properties of composites. M40 carbon fiber-reinforced aluminum composites (Gr_f/Al) with different matrix were fabricated by a pressure infiltration method. Fracture surfaces were characterized by scanning electron microscopy (SEM), while the microstructure was investigated by transmission electron microscopy (TEM). With the increase of Mg content, the formation of brittle Al_4C_3 phase is suppressed, which results in an intermediate interface bonding, therefore improves the mechanical properties of composites.
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