Study on the Design Method of Ring Groove Rivet Joint in Aluminum Alloy Structure

Jianpeng Sun,Xiaomeng Qu,Chang Gao 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.1

In this paper, the infl uence of the two main parameters of end distance and edge distance on high strength aluminum alloy ring groove rivet node failure mode, load–displacement curve and other mechanical property are studied. Many FEMs (fi nate element model) are established by ABAQUS software for comparative analysis under diff erent parameters. The FEM analysis results showed that the high-strength aluminum alloy ring-groove rivet connection is the pressure-bearing connection. Compared with the bolt connection, the high-strength aluminum alloy ring-groove rivet connection has good ductility, and the yield platform of the load–displacement curve is longer. The failure forms of high-strength aluminum alloy ring-groove rivet connection mainly include rivet shear failure, plate cross-section tearing and longitudinal section tearing failure. In order to avoid the above-mentioned damage, the recommended value of the edge distance is 2d 0 , and the end distance is recommended to take the value 2.5d 0 . Under the action of shear force, the stress stage of the high-strength aluminum alloy ring-groove rivet connection can be divided into four stages: friction, slippage, pressure bearing and strengthening; The shear and compressive bearing capacity of rivets under the two connection modes of single cover plate overlap and double cover plate butt joint is studied by changing the value of diff erent d/t ratio. Based on the relevant calculation formulas in the European aluminum alloy design code, the shear and compressive bearing capacity correction formulas suitable for the connection of domestic high-strength aluminum alloy rivets are derived. The research provides a reference basis for the ring-groove rivet connection of aluminum alloy nodes and improves the design specifi cations of aluminum alloy structures.

Comprehensive evaluation of natural enemy dominant species of Breuipalpus oboyats in tea garden in autumn and winter

Zhang Lin,Sun Jiazhao,Wu Xiaomeng,Xu Yu,Bi Shoudong,Zou Yunding 한국곤충학회 2021 Entomological Research Vol.51 No.12

The purpose of this study was to comprehensively evaluate the dominant natural enemies of Breuipalpus oboyats in autumn and winter tea gardens. The relationship between natural enemies and B.oboyats in time and space was studied by niche analysis and geostatistics combined with angular cosine coefficient method. According to the comparison of the sum of closeness index, it is found that the top three natural enemies (from large to small) that are most closely related to B.oboyats in the “Nongkangzao” tea garden are Plexippus paykulli, Clubiona japonicola,and Xysticus ephippiafus; “Pingyangtezao” tea garden are X.ephippiafus, Plexippus setipet,andOxyopes sertatus. In front of the two tea gardens, one of the three natural enemies is the same. The evaluation of the comprehensive closeness index of the two tea gardens shows that the top three natural enemies most closely related to B.oboyats are X.ephippiafus, P.paykulli, and O.sertatus. X.ephippiafus is the most important natural enemy of B.oboyats in tea gardens in autumn and winter; the dominant natural enemies of the same pests in different varieties of tea gardens in the same area are often different.

Evaluation of the close degree of the spatial relationship between natural enemies of tea gardens and Frankliniella intonsa based on variance analysis of cluster samples

Honghao Cheng,Shiyan Chen,Xiaomeng Wu,Yue Xu,Lin Zhang,Jiazhao Sun,Xiazhi Zhou,Yunding Zou,Shoudong Bi 한국곤충학회 2022 Entomological Research Vol.52 No.6

The aim of this paper is to clarify the difference of spatial closeness between natural enemies and Frankliniella intonsa, and to provide a scientific basis for rational protection and utilization of natural enemies. This paper applied the block-sample square difference analysis method, Gray correlation degree method, the aggregation intensity index method and ρ index method to study the difference in the closeness of the spatial relationship between F. intonsa and natural enemies when the number of F. intonsa and their natural enemies was the highest and the minimum area occupied by F. i n t o n s a individuals and colonies in five tea plantations in Hefei, Anhui province in 2021 and four tea plantations in 2020. The results were as follows: 1) Tetragnatha squamata Karsch, Xysticus ephippiafus, Erigonidium graminicolum and Theridion Octomaculatum were the top four natural enemies closely related to F. intonsa in 2021. The top three natural enemies closely related to F. intonsa in 2020 were Tetragnatha squamata Karsch, Xysticus ephippiafus and Theridion Octomaculatum. Tw o y e a r s a g o , Tetragnatha squamata Karsch and Xysticus ephippiafus were the same. 2) Cluster size did not change the distribution patterns of natural enemies and F. intonsa. 3) The aggregation of F. intonsa was caused by their own causes or some environmental factors, and the aggregation of natural enemies was caused by environmental factors. 4) In 2021, the minimum area occupied by individuals and groups of F. intonsa in tea gardens was 2m2, and in 2020, it was 8 m2.

Analysis of the following effect of the natural enemies with Frankliniella intonsa in tea garden

Cheng Honghao,Chen Shiyan,Wu Xiaomeng,Xu Yue,Zhang Lin,Sun Jiazhao,Zhou Xiazhi,Zou Yunding,Bi Shoudong 한국곤충학회 2022 Entomological Research Vol.52 No.8

In order to reasonably protect and utilize natural enemies for comprehensive control of Frankliniella intonsa, a systematic investigation was conducted on F. i n t o n s a and natural enemies in tea gardens in Hefei, Anhui Province, and the spatial following effect of natural enemies on F. intonsa was studied. The semi-variogram of natural enemies and thrips was obtained by the geostatistics method, and the correlation degree between them was analyzed by the grey correlation degree analysis method. The higher the correlation degree between natural enemies and F. intonsa, the closer the relationship between natural enemies and F. intonsa was. In this study, we analyzed the relationship between 11 natural enemies of F. i n t o n s a in tea gardens from October 28, 2020 to November 20, 2020 and from August 22, 2021 to November 19, 2021. The top five natural enemies with the largest closeness index to F. intonsa in Huangshan Dayezhong tea garden are Oxyopes sertatus, Theridion octomaculatum, Plexippus setipes, Xysticus ephippiafus and Erigonidium graminicolum. The top five natural enemies with the largest closeness index to F. intonsa in Pingyang Tezao tea garden are Erigonidium graminicolum, Plexippus setipes, Xysticus ephippiafus, Oxyopes sertatus and Clubiona japonicola.Among the top five natural enemies in the two tea gardens, those in common are Oxyopes sertatus, Erigonidium graminicolum, Xysticus ephippiafus and Plexippus setipes. According to the summation of the closeness index and the sum of the serial numbers, the top five natural enemies closely related to the spatial following of F. intonsa in the tea gardens were Oxyopes sertatus, Plexippus setipes, Erigonidium graminicolum, Xysticus ephippiafus and Theridion octomaculatum. One of the factors closely related to the space of F. i n t o n s a in the same tea garden was the ratio of F. i n t o n s a to a certain natural enemy. The smaller the ratio was, the closer the following relationship was. The results of this study provide scientific basis for biological control and natural enemy protection of F. intonsa.

Comparison of dry- and wet-heat induced changes in physicochemical properties of whey protein in absence or presence of inulin

Feng Gao,Xuefei Zhang,Hao Wang,Xiaomeng Sun,Jiaqi Wang,Cuina Wang 한국식품과학회 2019 Food Science and Biotechnology Vol.28 No.5

Changes in whey protein (10%, w/v) induced bydry-heating (60 C for 5 days at a relative humidity of63%), wet-heating (85 C for 30 min) or the two-combinedheating in absence or presence of inulin (8%, w/v) werestudied. Mixture of whey protein and inulin showed significantlyhigher absorbance at 290 nm than whey proteinalone in all heating conditions while only dry-heatedsamples showed significantly increased absorbance value at420 nm (p\0.05). Whey protein after heating showedsignificantly lower zeta potential and inulin decreased thevalue of all heated samples further (p\0.05) except forsamples after dry-heating. Heating decreased the freesulfhydryl group content of whey protein samples whilepresence of inulin decreased further (p\0.05). Dry-heatingdecreased while wet-heating increased the surfacehydrophobicity of whey protein. Inulin had no effect on thesurface hydrophobicity of heated whey protein under dryheatingbut decreased under wet-heating.

Differences in the closeness of spatial relationship between Ricanidae in their prime and natural enemies in five kinds of tea gardens

Cheng Xian,Zhang Lin,Wu Xiaomeng,Xu Yue,Sun Jiazhao,Zhou Xiazhi,Zou Yunding,Bi Shoudong 한국곤충학회 2022 Entomological Research Vol.52 No.8

To identify the natural enemy species which are close to Ricanidae in spatial relationship and to provide scientific basis for biological control and reasonable protection of natural enemies, geostatistics and the angular cosine coefficient method were used to analyze the population of Ricanidae in their prime and their natural enemies in the Anji white tea garden, the Longjing43 tea garden, the Nongkangzao tea garden, the Pingyangtezao tea garden and the Wuniuzao tea garden. The spatial relationship between six natural enemies and Ricanidae was also studied. The angular cosine coefficients were normalized to obtain the intimacy index. According to the sum of the intimacy index and the serial number of the intimacy index of each natural enemy in five tea gardens, the following conclusions could be drawn: the top three natural enemies closely related to Ricanidae in spatial relationship were Clubiona reichlini, Clubiona japonicola and Misumenops tricuspidatus; at least two species of the top three natural enemies in each tea garden were the same as the top three natural enemies in the comprehensive analysis of the five tea gardens; one of the factors that determined the spatial relationship between natural enemies and Ricanidae was the ratio of the number of Ricanidae and natural enemies. The results of this study identified the spider species of natural enemies which should be rationally used and protected in the five tea gardens.

Systematical characterization of functional and antioxidative properties of heat-induced polymerized whey proteins

Feng Gao,Xuefei Zhang,Jiaqi Wang,Xiaomeng Sun,Cuina Wang 한국식품과학회 2018 Food Science and Biotechnology Vol.27 No.6

Effects of pH (6–8), protein concentration (6–11%, w/v), heating temperature (70–95 C) and time (5–30 min) on functional and antioxidative properties of heat-induced polymerized whey protein were systematically investigated. All samples were determined for solubility at pH 4.6, emulsion capacity and stability, and antioxidative properties involving 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,20-azinobis(2-ethylbenzothiazoline- 6-sulfonate) (ABTS) scavenging abilities. Heating resulted in significant loss in solubility, emulsion capacity and stability for whey protein, p\0.05. Heating decreased DPPH but enhanced ABTS scavenging ability for whey protein significantly, p\0.05. Changes caused by pH variation were much stronger than those observed for other factors. Both protein concentration and heating time had negative effects while heating temperature had positive effect on emulsion capacity of whey protein. Data indicates that functional and antioxidative properties of whey protein could be altered by factors including pH, protein concentration, heating temperature and time.

Polyamidoamine Immobilized TEMPO Mediated Oxidation of Cellulose: Effect of Macromolecular Catalyst Structure on the Reaction Rate, Oxidation Degree and Degradation Degree

Huazhe Liang,Meng Cao,Desheng Yang,Tingting Sun,Xiaomeng Chu,Shaojie Liu 한국섬유공학회 2020 Fibers and polymers Vol.21 No.6

A series of polyamidoamine (PAMAM) immobilized TEMPO macromolecular catalysts were prepared by condensation reduction reactions between carbonyl groups in 4-O-TEMPO and primary amines in PAMAM. The macromolecular catalyst and NaBr/NaClO were used as catalytic system for selective oxidation of cellulose in aqueous medium. Effects of various factors, such as TEMPO loading ratios and PAMAM generations, were studied on the catalytic performances. Compared with free TEMPO, the macromolecular catalyst with less than 50 % TEMPO loading ratio had a higher reaction rate in the initial stage of the reaction. Especially, the reaction rate of G1.0 PAMAM with 30 % TEMPO loading ratio was comparable to free TEMPO in the whole reaction process. Its cellulose oxidation degree (or catalytic activity) was also equivalent to the level of free TEMPO. Interestingly, the cellulose depolymerization degree of macromolecular catalyst was not affected by the cellulose oxidation degree and was lower than that of free TEMPO. The macromolecular catalyst could be recycled efficiently by the combination of supernatant circulation and salting-out extraction, and the recycling performance was excellent.

Developing homogeneous ion exchange membranes derived from sulfonated polyethersulfone/N-phthaloyl-chitosan for improved hydrophilic and controllable porosity

Zhixue Li,Zhun Ma,Yuting Xu,Xiaomeng Wang,Yongchao Sun,Rong Wang,Jian Wang,Xueli Gao,Jun Gao 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.8

Ion exchange membranes (IEMs) composed of sulfonated poly (ether sulfone) (SPES) and N-phthaloyl chitosan (NPHCs) were synthesized. NPHCs was employed in membrane fabrication to improve the porosity and hydrophilicity of membranes. The effect of blend ratio of sulfonation (DS) and NPHCs content on physico-chemical characteristics of home-made membranes was investigated. The morphology of prepared membranes was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD) and scanning electron microscopy (SEM). SEM images revealed the formation of a more porous membrane structure and smoother surface. The electrochemical and physical properties of CEMs were characterized comprising water content, contact angle, ion exchange capacity (IEC) and thermal stability. Membrane water content, surface hydrophilicity and IEC were enhanced with increase of DS and NPHCs blend ratios in casting solution. Furthermore, the diffusion coefficient was also improved slightly with increase of DS and NPHCs blend ratios in prepared membranes. Membrane potential, permselectivity, transport number and areal membrane resistance all showed decreasing trends by the increase in NPHCs blend ratio in casting solution. These results indicated that the prepared membrane has good prospective and great potential for desalination in electrodialysis applications.