On the plane geometry design method of the loop-free hyperbolic single-layer cable structures

Renjie Liu,Jiajia Cao,Hang Zhao,Su-Duo Xue,Guangyong Wang,Jin Liang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.10

The plane geometry design of the cable-net structure is the basis for the form-finding and structural design. The loop-free single-layer cable-net structure is a new cable-net scheme, but due to its special and complex shape, it is difficult to determine its plane geometry according to architectural requirements. In this paper, the moving support node method is proposed, which can quickly get the plane geometry of a loop-free single-layer cable-net structure. The form-finding is proceeded based on the existing small elastic modulus method. There are two constraints when using the moving support node method. One is that the projection of all cables is straight line, and the other is that the distance between the two cables of each support node and the inner boundary of the target is equal. The aim is to minimize the sum of the distances from all cables to the inner boundary of the target. Using the plane geometry control parameters and the plane coordinates of the support nodes as decision variables, the plane geometry closest to the target inner and outer boundaries is get through optimization analysis. According to the derivation of the formula, the plane projection shape of a loop-free single-layer cable-net structure is mainly related to three parameters, including the number of supports, the difference between the node numbers of the supports at both ends of each cable, and the target curve equations of the inner and outer boundaries. Finally, taking the roof structure of Linyi Olympic Stadium as an instance, the feasibility of the plane geometry design method of the loop-free single-layer cable-net structures based on the moving support node method is verified.

Treatment of wastewater containing linear alkylbenzene sulfonate by bacterial-microalgal biological turntable

Renjie Tu,Wenbiao Jin,Song-fang Han,Binbin Ding,Shu-hong Gao,Xu Zhou,Shao-feng Li,Xiaochi Feng,Qing Wang,Qinhui Yang,Yu Yuwen 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.5

Linear alkylbenzene sulfonate (LAS), which is widely used as detergent, is a common toxic pollutant in wastewater. Generally, biodegradation process is applied to remove LAS. However, the efficiency of traditional wastewater treatment cannot meet the growing demand. In this study, an improved biological turntable with a symbiotic system of bacteria and microalgae was primarily used to enhance the biodegradation efficiency of LAS from wastewater. The symbiotic system of bacteria and microalgae was mainly composed of Scenedesmus dimorphus and three LAS-degrading bacteria Plesiomonas sp. (L3, L7) and Pseudomonas sp. (H6). The average removal rate of LAS was up to 94.6%. The LAS concentration of the effluent of the system decreased by 81.7% after the bacterial-microalgae inoculation (the inoculation temperature was 25 oC; microalgae were inoculated at a concentration of 10% only at the start of the system; bacteria were continuously inoculated at 1‰ concentration). After bacterial-microalgae inoculation, the average effluent concentration of CODCr in the tertiary reaction tank was 24.3mg/L, the average membrane effluent concentration was 15.8mg/L, and the average removal rate was 90.5%. Compared with the control group without inoculation, the concentration of CODCr in the tertiary reaction tank and membrane effluent decreased by 55.7% and 46.4%. The denaturing gradient electrophoresis (DGGE) pattern analysis of the systemic flora showed that there were two dominant species of high LAS degrading bacteria. They were identified to belong to Plesiomonas sp. and Pseudomonas sp., respectively.

On the Collapse Resistance of the Levy Type and the Loop-Free Suspen-Dome Structures After Accidental Failure of Cables

Renjie Liu,Yao Zou,Guangyong Wang,Suduo Xue 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.2

Current Levy type suspen-domes use loop cables which are key elements and carry large tensions. The loop-free suspendome was proposed for improving the collapse resistance and reducing cable tensions. However, the collapse resistance of the loop-free suspen-dome after accidental failure of cables has not been verifi ed and its key element is not clear. In this paper, analysis on the collapse resistance of both the Levy type suspen-dome and the loop-free suspen-dome after accidental failure of cables is performed based on the AP method by considering dynamic eff ect and non-linearity. The displacements and residual bearing capacity of 34 cable-rupture schemes are discussed, the eff ect on the cable tension and failure mode are also analyzed. It turns out that collapse resistance of the loop-free suspen-dome is better than the Levy type suspen-dome. The failure of cables does not infl uence the tension of remaining cables obviously so that the loop-free cable-strut system has suffi cient stiff ness and provides support and restraint for the reticulated shell. The most important cable in the loop-free suspen-dome is located in the outermost layer of the cable-strut system. It is also found that whether progressive collapse of the suspen-dome occurs after accidental failure of cables depends on both the bearing capacity of the reticulated shell and the residual contribution of the cable-strut system.

Controllable Curve Fitting Based Swing Door Trending Algorithm and its Application in Process Data Compression

Song Renjie,Zhang Qinghe,Liu Haiyang,Yang Shuo,Wang Zhaohui,Bao Zhen 보안공학연구지원센터 2016 International Journal of Database Theory and Appli Vol.9 No.11

Swing door trending (SDT) algorithm is a lossy compression algorithm that be applied on the real-time database and proposed by OSI software company of American; SDT is widely used to compress process data generated by process industry. Using straight line for a data section to linear fitting in traditional SDT algorithm. However, the data generated in the process of industrial production are slightly fluctuating with time. So, the use of linear fitting will lead to a large decompression error. In order to overcome the large decompression error generated by the traditional SDT, we proposed Controllable Curve Fitting Based Swing Door Trending (CCFSDT). The CCFSDT algorithm uses curve line for a data section to fitting, the data restored are closer to the true value. And in order to reduce the cost of curve fitting, it can be appropriate to reduce the total number of points of curve fitting. We filter noise point before fitting to void the impact on the reduction data and achieve better compression effect. The experimental results on simulated data and actual plant data show that: under the same conditions, the CCFSDT can well reduce the errors of decompression and achieve satisfactory performance.

An Investigation of Surface Tracking Characteristics and Factors Influencing Epoxy Resin Pouring Insulation for Dry-type Reactors

Yongqiang Wang,Han Liu,Wenpeng Li,Renjie Ding 한국고분자학회 2019 Macromolecular Research Vol.27 No.3

This study aimed to understand the deterioration mechanisms of epoxy resin pouring insulation for outdoor dry-type reactors under the effect of long-term surface tracking discharge. Epoxy resin insulation boards similar to the main insulation composition of the dry-type reactor were poured as the experimental material. A tracking experimental platform of insulation materials was built using an inclined plate method. The tracking discharge characteristics and surface erosion of the insulation materials were measured and analyzed. The characteristics of partial discharge, erosion, hydrophobicity and surface roughness were measured experimentally. Surface morphology, three-dimensional morphology and Fourier infrared images at different stages during erosion of the epoxy resin insulation material were analyzed. The effect of glass fiber content on the tracking resistance to erosion was characterized. The results show that the tracking process of epoxy resin insulation material experienced initiation, stability, development and outbreak periods. The flashover discharge corresponding to the development period was the main reason for the carbonization of the insulating material. During the tracking process, with a change in surface topography and formation of surface products, the surface roughness of the material generally increased along with the surface roughness which rose fastest during the discharge outbreak period. The changes in the surface morphology and three-dimensional morphology of the epoxy resin material constitute the basis for assessing the condition of the insulation surface and development of the erosion. The discharge capacity of epoxy resin generally shows an exponential increase. Adding 20 wt% of glass fibers that are evenly distributed and have reduced exposure can improve the tracking resistance of epoxy resin insulation materials.

Biomechanical Study of 3 Osteoconductive Materials Applied in Pedicle Augmentation and Revision for Osteoporotic Vertebrae: Allograft Bone Particles, Calcium Phosphate Cement, Demineralized Bone Matrix

Chongyu Jia,Renjie Zhang,Jiaqi Wang,Bo Zhang,Huaqing Zhang,Liang Kang,Luping Zhou,Cailiang Shen 대한척추신경외과학회 2023 Neurospine Vol.20 No.4

Objective: This study assessed biomechanical properties of pedicle screws enhanced or revised with 3 materials. We aimed to compare the efficacy of these materials in pedicle augmentation and revision. Methods: One hundred twenty human cadaveric vertebrae were utilized for in vitro testing. Vertebrae bone density was evaluated. Allograft bone particles (ABP), calcium phosphate cement (CPC), and demineralized bone matrix (DBM) were used to augment or revise pedicle screw. Post the implantation of pedicle screws, parameters such as insertional torque, pullout strength, cycles to failure and failure load were measured using specialized instruments. Results: ABP, CPC, and DBM significantly enhanced biomechanical properties of the screws. CPC augmentation showed superior properties compared to ABP or DBM. ABP-augmented screws had higher cycles to failure and failure loads than DBM-augmented screws, with no difference in pullout strength. CPC-revised screws exhibited similar strength to the original screws, while ABP-revised screws showed comparable cycles to failure and failure loads but lower pullout strength. DBM-revised screws did not match the original screws’ strength. Conclusion: ABP, CPC, and DBM effectively improve pedicle screw stability for pedicle augmentation. CPC demonstrated the highest efficacy, followed by ABP, while DBM was less effective. For pedicle revision, CPC is recommended as the primary choice, with ABP as an alternative. However, using DBM for pedicle revision is not recommended.

Experimental study on the axial bearing capacity of built-up cold-formed thin-walled steel multi-limb-section columns

Wentao Qiao,Yuhuan Wang,Renjie Zhu,Ruifeng Li,Mingshan Zhao 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.6

To solve the shortcomings of single-limb or double-limb cold-formed thin-walled steel column easy to buckling failure and low bearing capacity, a new cross-shaped built-up cold-formed thin-walled steel multi-limb-section is proposed for columns. The structure is composed of several single-limb cold-formed thin-walled steel C-channel sections. The flanges and webs are connected by self-drilling screws. In order to assess the mechanical properties of this built-up multi-limb-section column and the influence of the slenderness ratio on the column behavior, the axial loading tests were carried out. Three kinds of single-limb column and built-up multi-limb-section column with different ratio of slenderness were tested. The deformation process, failure mode and bearing capacity were analyzed. The SC specimens failed with local buckling and distorted buckling, while the MC and LC specimens failed with local buckling and global instability. For the built-up multi-limb-section column, the section combination multiple is 12. Compared to the section combination multiple, the bearing capacity combination multiple is much higher. The SQ specimens’ combination factor is about 1.1, the combination factor of MQ specimens and LQ specimens are about 1.4 and 3.0, respectively. It is concluded that the overall combined-performance and structural efficiency of the specimens is proportional to the combination factor.

Alum sludge conditioning with ferrous iron/peroxymonosulfate oxidation: Characterization and mechanism

Xu Zhou,Wenbiao Jin,Lan Wang,Lin Che,Chuan Chen,Shao-feng Li,Xue-Ting Wang,Renjie Tu,Song-fang Han,Xiaochi Feng,Nan-Qi Ren 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.4

Alum sludge produced by drinking water plants needs to be conditioned and dewatered before final disposal. In this study, a novel ferrous iron/peroxymonosulfate (PMS) oxidation process was employed to enhance alum sludge dewaterability. The effect of oxidative sulfate radicals generated by Fe2+ activated HSO5  on alum sludge was studied. The results showed that the optimal conditioning conditions for addition of Fe2+ and PMS were 0.5 g/g and 0.1 g/g TSS, respectively. Meanwhile, the capillary suction time (CST) and specific resistance to filtration (SRF) of alum sludge was reduced by 66% and 88%. Also found was that the absolute value of the zeta potential increased and the particle size decreased in alum sludge after Fe2+-PMS conditioning, which indicated that oxidative sulfate radicals destroyed the floc structure of alum sludge and smaller particles were generated. At the same time, the water contained in sludge flocs was released and enhanced sludge dewaterability, while leaching of aluminum ions also characterized decomposition of alum sludge.

Composite Materials : SOLIDIFICATION PROCESSLNG OF METAL MATRIX COMPOSITES AND ITS EFFECTS ON COMPOSITES MECHANICAL PROPERTIES

Guohong Xie Songchun Li,Wuxian Wang,Renjie Wu 대한금속재료학회 ( 구 대한금속학회 ) 1995 Advanced Material and Processing Vol.3 No.-

Improving primary sludge dewaterability by oxidative conditioning process with ferrous ion-activated peroxymonosulfate

Xu Zhou,Wenbiao Jin,Lan Wang,Wanqing Ding,Chuan Chen,Xijun Xu,Renjie Tu,Song-fang Han,Xiaochi Feng,Duu-Jong Lee 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.9

Enhancement of sludge dewaterability is key for sludge management and disposal of wastewater treatment plants (WWTP). In this study, the Fe2+-peroxymonosulfate (PMS) conditioning approach was first used to oxidize the primary sludge from the primary sedimentation tank of a full scale WWTP. The combination of Fe2+ (0.05-0.5 g/g TSS) and PMS (0.05-0.5 g/g TSS) could significantly improve the dewaterability of primary sludge. The optimal addition amount of Fe2+ and PMS was 0.1 g/g TSS and 0.25 g/g TSS, respectively, under which the capillary suction time (CST) and specific resistance to filtration (SRF) of the sludge was reduced by 79% and 95%. The physicochemical properties (particle size, zeta potential, EPS composition) of the primary sludge before and after oxidative conditioning were measured. Results showed that sulfate radicals generated from Fe2+-PMS system effectively reduced organic matter in different EPS fractions, further destroying sludge floc cells. Then the bound water in the sludge flocs was released, thereby improving the sludge dewaterability. The microscopic morphology also indicated that the sludge flocs have a blocky structure with tight texture before conditioning. After conditioning, the sludge flocs become smaller, and many irregular pores are formed on the surface, which facilitates the passage of internal moisture. Economic analysis showed that Fe2++PMS conditioning is more economical than the traditional Fenton method.