Optimization of a piezoelectric wind energy harvester with a stepped beam

Jiantao Zhang,Dong Qu,Zhou Fang,Chang Shu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.11

A galloping-based piezoelectric energy harvester using the stepped cantilever beam is proposed and investigated. Transverse galloping is induced with the square cross sectioned bluff body. When the wind speed exceeds the critical wind speed, the self-excited oscillation of the harvester occurs and more output power is generated. To obtain the optimal design of the energy harvester, the sequential quadratic programming (SQP) and the evolution strategy (ES) are employed to determine the optimal solution. The finite element method is used to calculate the output voltage of the harvester. After optimization, the output voltage of the optimal harvester is significantly improved in comparison with that of the initial one. Two prototype harvesters based on the initial and optimal dimensions were fabricated and measured experimentally. An open-circuit rms voltage of 36 V and an output power of 0.52 mW were obtained at the wind speed of 14 m/s for the optimal harvester. They are about 8.3 times and 4.73 times of that of the initial harvester. The validity of the optimal design is verified with the experimental results.

Genetic architecture of flag leaf length and width in rice (Oryza sativa L.) revealed by association mapping

Jiantao Wu,Yongwen Qi,Guanglong Hu,Jinjie Li,Zichao Li,Hongliang Zhang 한국유전학회 2017 Genes & Genomics Vol.39 No.3

Rice flag leaf is the main photosynthetic organ and plays a key role in grain yield. In this study, 106 loci associated with flag leaf length and width were identified using association mapping in a rice mini core collection. Analyzing the phenotypic effects of each allele represented 156 positive and 167 negative alleles, with a few alleles showing inconsistent effect in different environments. Among the 106 loci, 69 were environment-specific loci, 16 were environmentally stable and 21 were environmentally sensitive. Fifteen associated markers were shared by two traits and were designated as pleiotropic markers. According to the frequency distribution of alleles in different variety types, 343 alleles were categorized into three types based on geographic source and usage in breeding. Among these, 156 were used alleles, 138 were unused and 49 were foreign alleles. The results further our understanding of the genetic mechanisms of flag leaf length and width.

Selection of inspection path optimization scheme based on analytic hierarchy process and inspection experimental study

Shuo Zhang,Jiantao Yao,Ruochao Wang,Yu Tian,Jiaxin Wang,Yongsheng Zhao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.1

This paper mainly studies the optimization of the patrol route of a fire inspection robot, based on analytic hierarchy process (AHP) and fire source detection. First, the A* algorithm is improved based on two aspects of the heuristic function and of the obstacle boundary setting, while the suboptimal path is obtained in MATLAB. Next, the path planned according to the improved A* algorithm is smoothed and optimized, by means of gradient descent method, Bezier curve and B-spline curve, while the index parameters are optimized by means of MATLAB simulation. In view of the simulation results, the trajectory optimization performance index evaluation system, established by five decision criteria, including running time, path length, ride comfort, no-collision effect and quadratic optimization space, is put forward. The three kinds of optimization methods are analyzed qualitatively and quantitatively, and the results show that, in the total hierarchical ranking, the B-spline curve trajectory optimization scheme has the largest weight and is more important than the other two schemes. Finally, the superiority of B-spline curve is verified experimentally.

Effects of fermented feed on growth performance, nutrient metabolism and cecal microflora of broilers

Li Jiantao,Tao Lijuan,Zhang Rong,Yang Guiqin 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.4

Objective: To investigate the effects of enzyme-bacteria co-fermented feed on broilers, the basal diet (BF) was pretreated by microbial enzyme co-fermentation, and then different proportions of BF were replaced to study its effects on growth performance, nutrient metabolism and cecal microflora of broilers. Methods: Four hundred and eighty 1-day-old broilers were randomly divided into 6 groups. The control group was fed with BF, and groups 1 to 4 were treated with dried fermented feed (DFF) instead of 10%, 15%, 20%, and 25% the BF, and group 5 was treated with wet fermented feed (WFF) instead of 10% the BF, named BF, 10% DFF, 15% DFF, 20% DFF, 25% DFF, and 10% WFF, respectively. The trial period was 42 days. Results: The results showed that the average daily feed intake and average daily gain of 10% DFF, 15% DFF, and 10% WFF groups were significantly higher than those of the control group at 22 to 42 days and 1 to 42 days (p<0.05). Except for 10% DFF group, Firmicutes of all treatment were higher than that of control group. The Bacteroides of each treatment group were lower than that of the control group (p>0.05). At the same time, the nutrient apparent metabolic rate and cecal microbial abundance of each treatment group had an increasing trend (p>0.05). Conclusion: In conclusion, the feed fermented by enzyme and bacteria had a potential promoting effect on the growth performance and nutrient digestibility of broilers. Objective: To investigate the effects of enzyme-bacteria co-fermented feed on broilers, the basal diet (BF) was pretreated by microbial enzyme co-fermentation, and then different proportions of BF were replaced to study its effects on growth performance, nutrient metabolism and cecal microflora of broilers.Methods: Four hundred and eighty 1-day-old broilers were randomly divided into 6 groups. The control group was fed with BF, and groups 1 to 4 were treated with dried fermented feed (DFF) instead of 10%, 15%, 20%, and 25% the BF, and group 5 was treated with wet fermented feed (WFF) instead of 10% the BF, named BF, 10% DFF, 15% DFF, 20% DFF, 25% DFF, and 10% WFF, respectively. The trial period was 42 days.Results: The results showed that the average daily feed intake and average daily gain of 10% DFF, 15% DFF, and 10% WFF groups were significantly higher than those of the control group at 22 to 42 days and 1 to 42 days (p<0.05). Except for 10% DFF group, Firmicutes of all treatment were higher than that of control group. The Bacteroides of each treatment group were lower than that of the control group (p>0.05). At the same time, the nutrient apparent metabolic rate and cecal microbial abundance of each treatment group had an increasing trend (p>0.05).Conclusion: In conclusion, the feed fermented by enzyme and bacteria had a potential promoting effect on the growth performance and nutrient digestibility of broilers.

Ex vivo Expansion of Bone Marrow Mesenchymal Stem Cells Using Microcarrier Beads in a Stirred Bioreactor

Lang Zhou,Jiantao Kong,Ying-ping Zhuang,Ju Chu,Si-Liang Zhang,Mei-Jin Guo 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.1

Bone marrow mesenchymal stem cells (bmMSCs)have recently gained attention as a useful resource in the fields of regenerative medicine and tissue engineering. However, the number of bmMSCs obtained from available donors is very low. Here we developed a culture strategy for in vitro expansion of bmMSCs in a 1.5 L stirred bioreactor with microcarrier beads. First, the microcarriers (Cytodex 3) were equilibrated in culture medium containing 3% fetal bovine serum (FBS) for at least 30 min prior to cell addition. After inoculation, the FBS concentration of the medium was maintained at 3% (v/v) in the first 24 h and thereafter maintained at 1% (v/v) and a developed feeding regimen was applied over 5 days. The maximum cell density of 2.6 × 106 cells/mL was achieved at day 5,corresponding to a 10.4 ± 0.8 fold increases in total cell number. Among the harvested cells, 98.95% expressed CD29and 84.48% expressed CD90, suggesting that the majority of expanded bmMSCs still retained their differentiation potential. Therefore, the developed microcarrier-based stirred bioreactor culture system is an effective method to generate significant numbers of bmMSCs for potential applications and research studies.

Calculation Method of Underground Passage Excavation on Interactive Effects among Pipe-Roof, Steel Bracing and Foundation Soil

Chaoyang Heng,Song Sun,Jiantao Zhang,Zhi Zhou 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.1

The ultra-shallow buried excavation technology, utilizing pipe-roof steel arches as main supporting structure, has broad application prospects. Current mainstream pipe-roof design schemes often adopt simple beam theory or engineering analogy methods, which do not take into account the cumulative deformation and have high engineering disaster risk. Based on the beam Winkler model of elastic foundation, this paper studies the method on interactive effects among pipe-roof, steel bracing and foundation soil. The calculation model of the ultra-shallow buried pipe-roof and steel bracing is established with theoretical derivation. And a new supporting design method of ultra-shallow buried excavation under interactive effects is proposed. Firstly, an optimal method for determining the elasticity coefficient of steel arch and foundation soil is put forward on interactive effects among pipe-roof, steel bracing and foundation. Secondly, considering the enhancement effect of concrete wall, a procedure of determining the elasticity coefficient of fulcrum is described. That is, the first steel arch, which is adjacent to underground passage tunnel face, returns to the 1.5H (H is the height of the hole) range as an enhanced transition section, and the elasticity coefficient of fulcrum varies linearly with its position. Furthermore, the key issue is the deformation of the inlet section increases to a stable level in a certain range, while the ground settlement does not exceed the threshold. The selection of pipe-roof is controlled by calculated deformation. If the deformation meets the requirements, the internal force will be far enough to meet the requirements. Only two sections need to be considered when calculating the ultra-shallow buried underground passage, the entrances 2.0H and the central across section. Finally, the accuracy of the interactive effects calculated method is validated by using the measured data of a practical example.

A Coaxial and Off-axial Integrated Three-mirror Optical System with High Resolution and Large Field of View

Zhe Chen,Junqing Zhu,Jiantao Peng,Xingxiang Zhang,Jianyue Ren 한국광학회 2016 Current Optics and Photonics Vol.20 No.1

A novel optical design for high resolution, large field of view (FOV) and multispectral remote sensingis presented. An f/7.3 Korsch and two f/17.9 Cook three-mirror optical systems are integrated by sharingthe primary and secondary mirrors, bias of the FOV, decentering of the apertures and reasonable structurearrangement. The aperture stop of the Korsch system is located on the primary mirror, while those ofthe Cook systems are on the exit pupils. High resolution image with spectral coverage from visible tonear-infrared (NIR) can be acquired through the Korsch system with a focal length of 14 m, whilewide-field imaging is accomplished by the two Cook systems whose focal lengths are both 13.24 m. The full FOV is 4°×0.13°, a coverage width of 34.9 km at the altitude of 500 km can then be acquiredby push-broom imaging. To facilitate controlling the stray light, the intermediate images and the real exitpupils are spatially available. After optimization, a near diffraction-limited performance and a compactoptical package are achieved. The sharing of the on-axis primary and secondary mirrors reduces the costof fabrication, test, and manufacture effectively. Besides, the two tertiary mirrors of the Cook systemspossess the same parameters, further cutting down the cost.

Efficiency of gerAa, tupA and ca transformation in Bacillus subtilis for self-healing of concrete cracks

Hanxing He,Gefei Li,Jiantao Zhang,Jinlong Zhang,Mingyue Luo,Wenkai Hu,Yamin Lin,Ziyu Deng,Zhicheng Liu,Weizhao Chen,Xu Deng 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.5

A genetic approach was proposed to modify the characteristics of Bacillus subtilis strain WB800 (B. subtilis WB800) for selfhealing of concrete cracks. Three genes, namely gerAa which encodes germination receptors activated by L-alanine, tupA which is responsible for the synthesis of teichuronopeptide, and ca which encodes carbonic anhydrase (CA) catalyzing the synthesis of carbonate ion, were separately transformed into WB800. To protect bacterial cells from being squeezed, microspheres were produced with microcrystal cellulose (MCC) before the introduction of bacteria into the specimens. The results showed that the modified B. subtilis expressing GerA achieved 39.9% of germination ratio compared to 17% by the original host cells. With the transformation of tupA, the modified strain demonstrated higher resistance to alkaline environments, tolerating pH as high as 11, while the original strain only tolerated pH 9. The modified strain expressing CA induced more calcium carbonate than the original cells. Energy dispersive spectroscopy (EDS) identified the produced precipitate to be calcite (CaCO3). Moreover, a mathematical model was developed to optimize the influential factors of calcium precipitation process. Finally, based on the above results, an effective self-healing of concrete crack was achieved. This study may provide a promising strategy to improve the efficiency of bacterial self-healing of concrete cracks.

Prediction of Surface Settlement with Ultra-shallow-burial and Large Rectangular Cross-section Urban Underpass

Chaoyang Heng,Song Sun,Zhi Zhou,Jiantao Zhang 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.11

Based on the actual measured surface settlement of two super-shallow buried large rectangular-section urban underpass, a settlement fitting function is established. The superposition curve used the reduction of settlement trough. By comparing the results of fitting analysis with Peck formula result, settlement characteristics and simple prediction method for super-shallow and large rectangular section urban underpass are proposed, including: 1) The settlement trough is a superposition of three normal distribution curves, with the maximum surface settlement appeared above the central line of each single passage; 2) The depth and width of the middle passage settlement trough should be uniformly reduced. The reduction coefficient is calculated based on the ratio of the middle passage width to the side passage; 3) The loss rate of the side passage is 0.7% − 1.0%, while it is 0.4% − 0.6% for the middle passage, 4) If the underpass is excavated in staggered sequence, the peck formula can be used to calculate the surface settlement. The surface settlement of a single passage is calculated firstly, and then the surface settlement of three passages is superimposed to obtain the final settlement.