Influence of Screw Rotors Tip Angle on Mixing Performance for One Novel Twin-screw Kneader

Jing Wei,Dabing Chen,Dongming Zhou,Aiqiang Zhang,Yuliang Yang 한국고분자학회 2015 폴리머 Vol.39 No.3

Twin-screw kneader is an efficient polymer processing equipment. In this paper, the mixing performance of one novel intermeshing counter-rotating twin-screw kneader with different tip angles of the male rotor is simulated using the mesh superimposition technique (MST). Statistical analysis is carried out for the flow field using particle tracking technique, and distributive mixing performance is evaluated using the residence time distribution and segregation scale, while the dispersive mixing performance is estimated using the parameters such as shear rate, stretching rate and mixing index. The results show that the best distributive mixing performance is achieved when the tip angle is 0˚, while the optimal dispersive mixing performance is obtained when the tip angle is 20˚. The results in this paper provide a data basis for the selection of parameters and optimization of the performance for the screw rotors.

Estimation of Energy Savings when Adopting Ultrasonic Vibration-assisted Magnetic Compound Fluid Polishing

Chen Jiang,Jialei Huang,Zhenyu Jiang,Dabing Qian,Xiaolan Hong 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.1

Reducing energy use is a major consideration in green manufacturing. Ultrasonic vibration has the advantage of improving machining performance. This work presents an experimental investigation on magnetic compound fluid (MCF) polishing with and without ultrasonic vibration and estimates reductions in polishing energy consumption and surface roughness due to ultrasonic vibration during the machining process. A series of ultrasonic vibration-assisted MCF polishing (UVAMP) tests was carried out for brass H62, and the normal and tangential polishing forces, surface roughness and material removal rate of the traditional MCF polishing (MP) and UVAMP of brass were investigated for various machining parameters. The polishing energy consumptions during traditional MCF polishing and UVAMP were calculated and analyzed from the perspective of the energy of the polishing process. Results indicate that the use of UVAMP considerably reduces energy consumption and surface roughness during the polishing of brass. The adoption of UVAMP therefore has the potential to improve the efficiency and quality of polishing processes and offers a practical solution for the greener manufacturing of brass.

Post-meiotic Deficient Anther1 (PDA1) Encodes an ABC Transporter Required for the Development of Anther Cuticle and Pollen Exine in Rice

Lu Zhu,Jianxin Shi,Guochao Zhao,Dabing Zhang,Wanqi Liang 한국식물학회 2013 Journal of Plant Biology Vol.56 No.1

The tapetum of the anther locule encloses the malereproductive cells and plays a supportive role for normalpollen development. However, the underlying mechanismremains less understood. Previously, we identified a completerecessive male sterile mutant, post-meiotic deficient anther1(pda1), with abnormal postmeiotic tapetal development. Inthis study we comprehensively characterized pda1. Chemicalanalysis uncovered that pda1 anther had significant lowerlevels of cutin monomers and cuticular waxes. PDA1 geneencodes an ATP-binding cassette (ABC) half-transporter,namely OsABCG15, which is conserved from algae tohigher plants. In situ RNA hybridization assay showed thatPDA1 is strongly expressed in tapetal cells, and weakly inmicrospores during the anther development. Additionally,the expression of two pollen exine biosynthetic genesCYP704B2 and CYP703A3 was dramatically reduced inpda1 mutant anthers. Altogether, these observations suggestthat the tapetum-expressed ABC transporter PDA1 plays acrucial role in secreting lipidic precursors from the tapetumto developing microspores and the anther epidermis.

The Role of Rice Vacuolar Invertase2 in Seed Size Control

이대우,이상규,Md Mizanor Rahman,김유진,Dabing Zhang,전종성 한국분자세포생물학회 2019 Molecules and cells Vol.42 No.10

Sink strength optimizes sucrose import, which is fundamental to support developing seed grains and increase crop yields, including those of rice (Oryza sativa). In this regard, little is known about the function of vacuolar invertase (VIN) in controlling sink strength and thereby seed size. Here, in rice we analyzed mutants of two VINs, OsVIN1 and OsVIN2, to examine their role during seed development. In a phenotypic analysis of the T-DNA insertion mutants, only the OsVIN2 mutant osvin2-1 exhibited reduced seed size and grain weight. Scanning electron microscopy analysis revealed that the small seed grains of osvin2-1 can be attributed to a reduction in spikelet size. A significant decrease in VIN activity and hexose level in the osvin2-1 spikelets interfered with spikelet growth. In addition, significant reduction in starch and increase in sucrose, which are characteristic features of reduced turnover and flux of sucrose due to impaired sink strength, were evident in the pre-storage stage of osvin2-1 developing grains. In situ hybridization analysis found that expression of OsVIN2 was predominant in the endocarp of developing grains. A genetically complemented line with a native genomic clone of OsVIN2 rescued reduced VIN activity and seed size. Two additional mutants, osvin2-2 and osvin2-3 generated by the CRISPR/Cas9 method, exhibited phenotypes similar to those of osvin2-1 in spikelet and seed size, VIN activity, and sugar metabolites. These results clearly demonstrate an important role of OsVIN2 as sink strength modulator that is critical for the maintenance of sucrose flux into developing seed grains.

A rolling bearing fault diagnosis strategy based on improved multiscale permutation entropy and least squares SVM

Yongjian Li,Weihua Zhang,Qing Xiong,Dabing Luo,Guiming Mei,Tao Zhang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6

A novel rolling bearing fault diagnosis strategy is proposed based on Improved multiscale permutation entropy (IMPE), Laplacianscore (LS) and Least squares support vector machine-Quantum behaved particle swarm optimization (QPSO-LSSVM). Entropy-basedconcepts have attracted attention recently within the domain of physiological signals and vibration data collected from human body orrotating machines. IMPE, which was developed to reduce the variability of entropy estimation in time series, was used to obtain moreprecise and reliable values in rolling element bearing vibration signals. The extracted features were then refined by LS approach to form anew feature vector containing main unique information. By constructing the fault feature, the effective characteristic vector was input toQPSO-LSSVM classifier to distinguish the health status of rolling bearings. The comparative test results indicate that the proposed methodologyled to significant improvements in bearing defect identification.

Biological Synthesis of Nanoparticles from Plants and Microorganisms

Singh, Priyanka,Kim, Yu-Jin,Zhang, Dabing,Yang, Deok-Chun Elsevier 2016 Trends in biotechnology Vol.34 No.7

<P>Nanotechnology has become one of the most promising technologies applied in all areas of science. Metal nanoparticles produced by nanotechnology have received global attention due to their extensive applications in the biomedical and physiochemical fields. Recently, synthesizing metal nanoparticles using microorganisms and plants has been extensively studied and has been recognized as a green and efficient way for further exploiting microorganisms as convenient nanofactories. Here, we explore and detail the potential uses of various biological sources for nanoparticle synthesis and the application of those nanoparticles. Furthermore, we highlight recent milestones achieved for the biogenic synthesis of nanoparticles by controlling critical parameters, including the choice of biological source, incubation period, pH, and temperature.</P> <P><B>Trends</B></P> <P>The biological synthesis of nanoparticles is increasingly regarded as a rapid, ecofriendly, and easily scaled-up technology.</P> <P>Metal nanoparticles produced using microorganisms and plant extracts are stable and can be monodispersed by controlling synthetic parameters, such as pH, temperature, incubation period, and mixing ratio.</P> <P>Recently, biological nanoparticles were found to be more pharmacologically active than physicochemically synthesized nanoparticles.</P> <P>Among the various biological nanoparticles, those produced by medicinal plants have been found to be the most pharmacologically active, possibly due to the attachment of several pharmacologically active residues.</P>

<i>PgLOX6</i> encoding a lipoxygenase contributes to jasmonic acid biosynthesis and ginsenoside production in <i>Panax ginseng</i>

Rahimi, Shadi,Kim, Yu-Jin,Sukweenadhi, Johan,Zhang, Dabing,Yang, Deok-Chun Oxford University Press 2016 Journal of experimental botany Vol.67 No.21

<▼1><P><B>Highlight</B></P><P>In ginseng, jasmonic acid promotes expression of the biosynthetic genes for ginsenosides. <I>PgLOX6</I> encodes a lipoxygenase that is required for biosynthesis of jasmonic acid and its overexpression increases ginsenoside levels.</P></▼1><▼2><P>Ginsenosides, the valuable pharmaceutical compounds in <I>Panax ginseng</I>, are triterpene saponins that occur mainly in ginseng plants. It was shown that <I>in vitro</I> treatment with the phytohormone jasmonic acid (JA) is able to increase ginsenoside production in ginseng plants. To understand the molecular link between JA biosynthesis and ginsenoside biosynthesis, we identified a JA biosynthetic 13-lipoxygenase gene (<I>PgLOX6</I>) in <I>P. ginseng</I> that promotes ginsenoside production. The expression of <I>PgLOX6</I> was high in vascular bundles, which corresponds with expression of ginsenoside biosynthetic genes. Consistent with the role of <I>PgLOX6</I> in synthesizing JA and promoting ginsenoside synthesis, transgenic plants overexpressing <I>PgLOX6</I> in Arabidopsis had increased amounts of JA and methyl jasmonate (MJ), increased expression of triterpene biosynthetic genes such as <I>squalene synthase</I> (<I>AtSS1</I>) and <I>squalene epoxidase</I> (<I>AtSE1</I>), and increased squalene content. Moreover, transgenic ginseng roots overexpressing <I>PgLOX6</I> had around 1.4-fold increased ginsenoside content and upregulation of ginsenoside biosynthesis-related genes including <I>PgSS1</I>, <I>PgSE1</I>, and <I>dammarenediol synthase</I> (<I>PgDDS</I>), which is similar to that of treatment with MJ. However, MJ treatment of transgenic ginseng significantly enhanced JA and MJ, associated with a 2.8-fold increase of ginsenoside content compared with the non-treated, non-transgenic control plant, which was 1.4 times higher than the MJ treatment effect on non-transgenic plants. These results demonstrate that <I>PgLOX6</I> is responsible for the biosynthesis of JA and promotion of the production of triterpenoid saponin through up-regulating the expression of ginsenoside biosynthetic genes. This work provides insight into the role of JA in biosynthesizing secondary metabolites and provides a molecular tool for increasing ginsenoside production.</P></▼2>

Purification and Characterization of Novel Manganese Peroxidase from Rhizoctonia sp. SYBC-M3

Yujie Cai,Huiguang Wu,Xiangru Liao,Yanrui Ding,Jun Sun,Dabing Zhang 한국생물공학회 2010 Biotechnology and Bioprocess Engineering Vol.15 No.6

A novel manganese peroxidase of Rhizoctonia sp. SYBC-M3 (R-MnP) was purified by (NH4)2SO4fractionation, DEAE-cellulose-32 column chromatography,and Sephadex G100 column chromatography. The molecular mass of R-MnP was determined to be approximately 40.4 kDa by SDS-PAGE. The optimum temperature and pH for R-MnP were 55°C and 4.5, respectively. R-MnP was highly stability when the temperature was below 50°C. R-MnP could retain about 60% of its activity when the pH was between 4 and 6.5. However, R-MnP activity was inhibited by Fe3+, Cu2+, and Co3+ as well as increased by Zn2+ and Ca2+. R-MnP demonstrated oxidation of DMP,ABTS, veratryl alcohol, and guaiacol. The Km values of RMnP for H2O2 and Mn2+ were 25.3 and 53.9 μmol/L,respectively.

Defective Tapetum Cell Death 1 (DTC1) Regulates ROS Levels by Binding to Metallothionein during Tapetum Degeneration

Yi, Jakyung,Moon, Sunok,Lee, Yang-Seok,Zhu, Lu,Liang, Wanqi,Zhang, Dabing,Jung, Ki-Hong,An, Gynheung American Society of Plant Biologists 2016 Plant Physiology Vol.170 No.3

<P>After meiosis, tapetal cells in the innermost anther wall layer undergo program cell death (PCD)-triggered degradation. This step is essential for microspore development and pollen wall maturation. We identified a key gene, Defective Tapetum Cell Death 1 (DTC1), that controls this degeneration by modulating the dynamics of reactive oxygen species (ROS) during rice male reproduction. Mutants defective in DTC1 exhibit phenotypes of an enlarged tapetum and middle layer with delayed degeneration, causing male sterility. The gene is preferentially expressed in the tapetal cells during early anther development. In dtc1 anthers, expression of genes encoding secretory proteases or lipid transporters is significantly reduced, while transcripts of PCD regulatory genes, e.g. UDT1, TDR1, and EAT1/DTD, are not altered. Moreover, levels of DTC1 transcripts are diminished in udt1, tdr, and eat1 anthers. These results suggest that DTC1 functions downstream of those transcription factor genes and upstream of the genes encoding secretory proteins. DTC1 protein interacts with OsMT2b, a ROS scavenger. Whereas wild-type plants accumulate large amounts of ROS in their anthers at Stage 9 of development, those levels remain low during all stages of development in dtc1 anthers. These findings indicate that DTC1 is a key regulator for tapetum PCD by inhibiting ROS-scavenging activity.</P>

A Hybrid Self-Powered System Based on Wind Energy Harvesting for Low-Power Sensors on Canyon Bridges

Hao Cao,Xiaoping Wu,Hao Wu,Yajia Pan,Dabing Luo,Ali Azam,Zutao Zhang 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.1

Canyon cross wind has great potential to be transformed into electricity to power for low-power sensors of the health monitoring devices in bridge field. In this paper, a hybrid wind energy harvesting system (WEHS), integrating piezoelectric and electromagnetic mechanisms, is proposed to supply power for low-power sensors on canyon bridges. Firstly, the S-rotor embedded with a one-way bearing converts wind energy into rotational mechanical energy. Then, the piezoelectric cantilever beam and coils simultaneously convert mechanical energy into electricity under the excitation of the rotational magnet array. For the piezoelectric transducer, the symmetrical poles arrangement of tip magnet reduces the starting wind speed and resistance torque during energy harvesting. In addition, the relationship between different number of excitation magnets and the output of the piezoelectric transducer is explored. Finally, the output electricity is stored in the capacitors to supply power for low power sensors. The experimental results showed that the symmetrical poles arrangement of tip magnet could effectively reduce the starting resistance torque and improve the output power at low wind speeds. Given a wind speed of 6.5 m/s, the maximum output power of the WEHS can reach 19.24 mW with corresponding electrical energy of 75.714 mJ in one sweep period (6 s). The field test results demonstrated that the WEHS could effectively charge for the capacitors and power for a hundred LEDs. Furthermore, the mechanical durability and stability of the WEHS are verified by introducing a self-powered low power sensor system.