Fabrication of Al–Ti–B Grain Refiner Using Machining Ti Chips, Reaction Mechanisms and Grain Refinement Performance in Pure Al

Maoliang Hu,Fei Wang,Bo Jiang,Huasheng Wang,Yile Liu,Zesheng Ji 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

Al–5Ti–1B grain refiner was successfully prepared with the reaction of Ti chips produced during machining and KBF4inpure aluminum melt. In order to illustrate the reaction mechanism of Ti chips, the effect of different feeding ways and reactiontimes of Ti chips on microstructure and refining performance of Al–5Ti–1B was systematically investigated by opticalmicroscope, scanning electron microscopy and X-ray diffractometer. The results show that, in three feeding ways, includingadding Ti chips firstly, adding KBF4firstly and adding both Ti chips and KBF4in the form of prefabricated blocks, the bestrefining performance of Al–5Ti–1B is the feeding way of using the prefabricated block. TiB2and TiAl3as effective heterogeneousnuclei are formed simultaneously around the Ti chips. The average grain size of pure aluminum is refined to about206.80 μm. The reaction time mainly affects the dissolution process of Ti chips and the average size of TiAl3. With the reactiontime from 60 min to 90 min and then to 120 min, the average size of TiAl3increases from 10.74 μm to 14.30 μm and thento 15.39 μm. During the dissolution process, Ti chips undergo a transition from a thermal isolation layer to a supersaturatedzone of Ti atoms. Based on the analysis of the dissolution process of Ti chips, the dissolution model is proposed. Al–5Ti–1B has the best refining performance at 90 min of the reaction time, which can refine pure aluminum to about 223.65 μm.

Antimicrobial Activity of a Honeybee (Apis cerana) Venom Kazal-Type Serine Protease Inhibitor

Bo Yeon Kim,Kwang Sik Lee,Feng Ming Zou,Hu Wan,Yong Soo Choi,Hyung Joo Yoon,Hyung Wook Kwon,Yeon Ho Je,Byung Rae Jin 한국응용곤충학회 2013 한국응용곤충학회 학술대회논문집 Vol.2013 No.10

Insect-derived Kazal-type serine protease inhibitors exhibit thrombin, elastase, plasmin, proteinase K, or subtilisin A inhibition activity, but so far, no functional roles for bee-derived Kazal-type serine protease inhibitors have been identified. In this study, a bee (Apis cerana) venom Kazal-type serine protease inhibitor (AcKTSPI) that acts as a microbial serine protease inhibitor was identified. AcKTSPI contained a single Kazal domain that displayed six conserved cysteine residues and a P1 threonine residue. AcKTSPI was expressed in the venom gland and was present as a 10-kDa peptide in bee venom. Recombinant AcKTSPI Kazal domain (AcKTSPI-Kd) expressed in baculovirus-infected insect cells demonstrated inhibitory activity against subtilisin A (Ki 67.03 nM) and proteinase K (Ki 91.53 nM), but not against α-chymotrypsin or typsin, which implies a role for AcKTSPI as a microbial serine protease inhibitor. However, AcKTSPI-Kd exhibited no detectable inhibitory effects on factor Xa, thrombin, tissue plasminogen activator, or elastase. Additionally, AcKTSPI-Kd bound directly to Bacillus subtilis, B. thuringiensis, Beauveria bassiana, and Fusarium graminearum but not to Escherichia coli. Consistent with these findings, AcKTSPI-Kd showed antibacterial activity against Gram-positive bacteria and antifungal activity against both plant-pathogenic and entomopathogenic fungi. These findings constitute molecular evidence that AcKTSPI acts as an inhibitor of microbial serine proteases. This paper provides a novel view of the antimicrobial functions of a bee venom Kazal-type serine protease inhibitor.

An EID-based Fault Diagnosis Method for the Distribution Feeder with PV Generation Embedded

Hu, Bo,Yokoyama, Ryuichi,She, Jinhua,Zhou, Yicheng The Korean Institute of Electrical Engineers 2013 The Journal of International Council on Electrical Vol.3 No.3

This paper describes a new fault diagnosis method based on an equivalent-input-disturbance (EID) approach for distribution feeder with photovoltaics (PV) generation embedded. In this method, the faults are regarded as disturbances of system, which can be estimated by EID approach. Through analyzing the characteristics of the EID, the faults position can be located and the fault types can be identified. Firstly, a dynamic model of distribution feeder for fault diagnosis is built. Next, an EID estimator is designed. Finally, the simulation results demonstrate the effectiveness of the method.

Kinematics and dynamic analysis of a novel hybrid dynamics simulator

Bo Hu,Liandong Zhang,Jingjing Yu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.11

A serial-parallel dynamics simulator based on serial-parallel manipulator is proposed. According to the dynamics simulator motion requirement, the proposed serial-parallel dynamics simulator formed by 3-RRS (active revolute joint-revolute joint-spherical joint) and 3-SPR (Spherical joint-active prismatic joint- revolute joint) PMs adopts the outer and inner layout. By integrating the kinematics, constraint and coupling information of the 3-RRS and 3-SPR PMs into the serial-parallel manipulator, the inverse Jacobian matrix, velocity, and acceleration of the serial-parallel dynamics simulator are studied. Based on the principle of virtual work and the kinematics model, the inverse dynamic model is established. Finally, the workspace of the (3-RRS)+(3-SPR) dynamics simulator is constructed.

Reliability Evaluation Technique for Electrical Distribution Networks Considering Planned Outages

Hu, Bo,He, Xiao-Hui,Cao, Kan The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.5

The reliability evaluation of the electrical distribution networks (EDN) requires sufficient consideration of the effects of planned outages. The planned outages of the EDN can be divided, by outage models and their effects on the reliability into two major categories: by equipment and by feeder. After studying the characteristics of different categories of planned outages, this paper expands the classification of load points by outage time from 4 types to 7 types and defines corresponding reliability parameters for the different types. By using the section algorithm, this paper proposes a reliability evaluation technique of EDN considering equipment random failures and two categories of planned outages. The proposed technique has been applied to the RBTS-BUS6 test system and some practical EDNs in China. The study results demonstrate that the proposed technique is of higher practical value and can be used for evaluating the reliability performance of EDN more efficiently considering the planned outages.

Theoretical and experimental study on load-carrying capacity of combined members consisted of inner and sleeved tubes

Hu, Bo,Gao, Boqing,Zhan, Shulin,Zhang, Cheng Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.1

Load-carrying capacity of combined members consisted of inner and sleeved tubes subjected to axial compression was investigated in this paper. Considering the initial bending of the inner tube and perfect elasto-plasticity material model, structural behavior of the sleeved member was analyzed by theoretic deduction, which could be divided into three states: the elastic inner tube contacts the outer sleeved tube, only the inner tube becomes plastic and both the inner and outer sleeved tubes become plastic. Curves between axial compressive loads and lateral displacements of the middle sections of the inner tubes were obtained. Then four sleeved members were analyzed through FEM, and the numerical results were consistent with the theoretic formulas. Finally, experiments of full-scale sleeved members were performed. The results obtained from the theoretical analysis were verified against experimental results. The compressive load-lateral displacement curves from the theoretical analysis and the tests are similar and well indicate the point when the inner tube contacts the sleeved tube. Load-carrying capacity of the inner tube can be improved due to the sleeved tube. This paper provides theoretical basis for application of the sleeved members in reinforcement engineering.

Molecular cloning and characterization of a short peptidoglycan recognition protein (PGRP-S) with antibacterial activity from the bumblebee Bombus ignitus

Hu Wan,Kwang Sik Lee,Bo Yeon Kim,Hyung Joo Yoon,Hung Dae Sohn,Byung Rae Jin 한국응용곤충학회 2010 한국응용곤충학회 학술대회논문집 Vol.2010 No.05

Peptidoglycan recognition proteins (PGRPs) are pattern recognition molecules of the innate immune system that recognize peptidoglycan, a unique cell wall component of bacteria. Here we cloned and characterized PGRP-S from the bumblebee Bombus ignitus (BiPGRP-S). The BiPGRP-S gene consists of four exons encoding 194 amino acid residues. Comparative analysis indicates that the predicted amino acid sequence of BiPGRP-S shares high identity with enzymatically active PGRP-S proteins and contains the amino acids required for amidase activity. BiPGRP-S in B. ignitus worker bees is constitutively expressed in boththe fat body and epidermis, and it is secreted into the hemolymph. Quantitative real-time PCR assays revealed that in both the fat body and epidermis, the BiPGRP-S gene is highly induced by an injection of Bacillus thuringiensis. In addition, recombinant BiPGRP-S expressed as a 19-kDa protein in baculovirus-infected insect cells can bind to B. megaterium and B. thuringiensis but not to Staphylococcus aureus, Escherichia coli or Beauveria bassiana. Consistent with these data, BiPGRP-S shows antibacterial activity against B. megaterium and B. thuringiensis. These results indicate that BiPGRP-S is an inducible protein that may be involved in the immune response against bacterial infection of the genus Bacillus as an amidase-type PGRP-S.

Theoretical and experimental study on load-carrying capacity of combined members consisted of inner and sleeved tubes

Bo Hu,Boqing Gao,Shulin Zhan,Cheng Zhang 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.1

Load-carrying capacity of combined members consisted of inner and sleeved tubes subjected to axial compression was investigated in this paper. Considering the initial bending of the inner tube and perfect elasto-plasticity material model, structural behavior of the sleeved member was analyzed by theoretic deduction, which could be divided into three states: the elastic inner tube contacts the outer sleeved tube, only the inner tube becomes plastic and both the inner and outer sleeved tubes become plastic. Curves between axial compressive loads and lateral displacements of the middle sections of the inner tubes were obtained. Then four sleeved members were analyzed through FEM, and the numerical results were consistent with the theoretic formulas. Finally, experiments of full-scale sleeved members were performed. The results obtained from the theoretical analysis were verified against experimental results. The compressive load-lateral displacement curves from the theoretical analysis and the tests are similar and well indicate the point when the inner tube contacts the sleeved tube. Load-carrying capacity of the inner tube can be improved due to the sleeved tube. This paper provides theoretical basis for application of the sleeved members in reinforcement engineering.

OFPT: OpenFlow based Parallel Transport in Datacenters

( Bo Liu ),( Bo Xu ),( Chao Hu ),( Hui Hu ),( Ming Chen ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.10

Although the dense interconnection datacenter networks (DCNs) (e.g. FatTree) provide multiple paths and high bisection bandwidth for each server pair, the single-path TCP (SPT) and ECMP which are widely used currently neither achieve high bandwidth utilization nor have good load balancing. Due to only one available transmission path, SPT cannot make full use of all available bandwidth, while ECMP`s random hashing results in many collisions. In this paper, we present OFPT, an OpenFlow based Parallel Transport framework, which integrates precise routing and scheduling for better load balancing and higher network throughput. By adopting OpenFlow based centralized control mechanism, OFPT computes the optimal path and bandwidth provision for each flow according to the global network view. To guarantee high throughput, OFPT dynamically schedules flows with Seamless Flow Migration Mechanism (SFMM), which can avoid packet loss in flow rerouting. Finally, we test OFPT on Mininet and implement it in a real testbed. The experimental results show that the average network throughput in OFPT is up to 97.5% of bisection bandwidth, which is higher than ECMP by 36%. Besides, OFPT decreases the average flow completion time (AFCT) and achieves better scalability.

Reliability Evaluation of Power System Operations Considering Time-Varying Features of Components

Hu, Bo,Zheng, Ying,Yang, Hejun,Xia, Yun The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.4

The reliability of power system components can be affected by a numbers of factors such as the health level of components, external environment and operation environment of power systems. These factors also affect the electrical parameters of power system components for example the thermal capacity of a transmission element. The relationship of component reliability and power system is, therefore, a complex nonlinear function related to the above-mentioned factors. Traditional approaches for reliability assessment of power systems do not take the influence of these factors into account. The assessment results could not, therefore, reflect the short-term trend of the system reliability performance considering the influence of the key factors and provide the system dispatchers with enough information to make decent operational decisions. This paper discusses some of these important operational issues from the perspective of power system reliability. The discussions include operational reliability of power systems, reliability influence models for main performance parameters of components, time-varying reliability models of components, and a reliability assessment algorithm for power system operations considering the time-varying characteristic of various parameters. The significance of these discussions and applications of the proposed techniques are illustrated by case study results using the IEEE-RTS.