Mechanical and Microscopic Properties of Copper-contaminated Soil Solidified with Calcium Carbide Residue, Metakaolin, and Desulfurization Gypsum under Freeze-thaw Cycles

Qiang Wang,Dandan Ge,Guojun Cai,Man Li,Liuyan Wu,Huangrui Xu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.2

The solidification/stabilization effect of heavy metal contaminated soils in frozen soil regions may be weakened. A novel binder comprising calcium carbide residue, metakaolin, and desulfurization gypsum was used to solidify and stabilize copper-contaminated soil subjected to freeze-thaw (F-T) cycles. The unconfined compressive strength (UCS), F-T cycles, scanning electron microscope (SEM), X-ray diffraction (XRD), and pH tests were conducted to investigate the characteristics of UCS, deformation, pH value, and microscopic mechanism of contaminated soils. The results demonstrated that the UCS of contaminated soils decreased with the increasing F-T cycles and Cu2+ concentration; the strength loss rate increased first and then decreased as the F-T cycles increased. The failure strain rose first and then reduced with the increase of F-T cycles, and increased with the rise of Cu2+ concentration. There was a considerable correlation between UCS, failure strain, and deformation modulus E50. The pH value decreased with the increasing F-T cycles and Cu2+ concentration. The microscopic characteristics indicated that the formation of hydrated calcium silicate and ettringite was the fundamental reason for the enhanced UCS. Besides, heavy metals could be solidified and stabilized by chemical precipitation, physical encapsulation, and ion exchange. The effect of F-T cycles could significantly damage the internal structure of contaminated soils, and the frost heaving force could loosen the soil skeleton structure, leading to the deterioration of the mechanical properties.

A TYPE OF MODIFIED BFGS ALGORITHM WITH ANY RANK DEFECTS AND THE LOCAL Q-SUPERLINEAR CONVERGENCE PROPERTIES

Ge, Ren-Dong,Xia, Zun-Quan,Qiang, Guo 한국전산응용수학회 2006 Journal of applied mathematics & informatics Vol.22 No.1

A modified BFGS algorithm for solving the unconstrained optimization, whose Hessian matrix at the minimum point of the convex function is of rank defects, is presented in this paper. The main idea of the algorithm is first to add a modified term to the convex function for obtain an equivalent model, then simply the model to get the modified BFGS algorithm. The superlinear convergence property of the algorithm is proved in this paper. To compared with the Tensor algorithms presented by R. B. Schnabel (seing [4],[5]), this method is more efficient for solving singular unconstrained optimization in computing amount and complication.

AntagomiR-27a Targets FOXO3a in Glioblastoma and Suppresses U87 Cell Growth in Vitro and in Vivo

Ge, Yun-Fei,Sun, Jun,Jin, Chun-Jie,Cao, Bo-Qiang,Jiang, Zhi-Feng,Shao, Jun-Fei Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.2

Objective: To study the effect of the antagomiR-27a inhibitor on glioblastoma cells. Methods: The miR-27a expression level in specimens of human glioblastoma and normal human brain tissues excised during decompression for traumatic brain injury was assessed using qRT-PCR; The predicted target gene of miR-27a was screened out through bioinformatics databases, and the predicted gene was verified using genetic report assays; the effect of antagomiR-27a on the invasion and proliferation of glioma cells was analyzed using MTT assays and 5-ethynyl-2'-deoxyuridine (EdU) labeling. A xenograft glioblastoma model in BALB-c nude mice was established to detect the effect of antagomiR-27a on tumour growth. Results: qRT-PCR results showed that miR-27a significantly increased in specimens from glioblastoma comparing with normal human brain tissues. Th miR-27a inhibitor significantly suppressed invasion and proliferation of glioblastoma cells. FOXO3a was verified as a new target of miR-27a by Western blotting and reporter analyzes. Tumor growth in vivo was suppressed by administration of the miR-27a inhibitor. Conclusion: MiR-27a may be up-regulated in human glioblastoma, and antagomiR-27a could inhibit the proliferation and invasion ability of glioblastoma cells.

Parameter optimization of electromagnetic pulse compaction driven by aluminum tube for tungsten copper powder

Fen-Qiang Li,Juehao Ding,Miao Zheng,Jianlin Xu,Xiaohong Ge,Hui Li,Jun Zhao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7

A combination of multi-physics numerical simulation and experiment was conducted to study the magnetic pulse compaction technology driven by two aluminum tubes of tungsten copper powder. Then, the effects of different process parameters on the density and uniformity of the compact were studied by tuning the thickness of the pack and driver tubes and the gap between them. Results show that the density of compact is the highest when the thickness of the driver tube is 1.0 mm. More energy is consumed for force conduction as the thickness of the pack tube increases. Thus, the density of the compact is the highest when the thickness of the packer tube is 0.8 mm. The speed of the driver tube impacting the pack tube also increases with the rise in the gap. Accordingly, the compaction density with the gap of 1.5 mm is the highest under the same other parameters.

Purification, Chemical Characterization, and Antioxidant Activity of a Polysaccharide from the Fruiting Bodies of Sanghuang Mushroom (Phellinus Baumii Pilát)

Qing Ge,Jian-wei Mao,An-qiang Zhang,Yong-jiang Wang,Pei-long Sun 한국식품과학회 2013 Food Science and Biotechnology Vol.22 No.2

A purified water-soluble polysaccharide was isolated from the fruiting bodies of sanghuang mushroom (Phellinus baumii Pilát) using hot water extraction, DEAE Sepharose Fast Flow anion exchange and High-Resolution Sephacryl S-1000 gel-filtration chromatography. The purified polysaccharide was a complex β-D-glucan, with a molecular mass of 230 kDa. Fourier-transform infrared (FT-IR), methylation analysis, and NMR spectroscopy of sanghuang mushroom polysaccharide (PBF3) indicated that the polysaccharide contained (1→3)-β-D-, (1→4)-β-D-,and branched (1→3,6)-β-D-glucopyranosyl residues. On the basis of hydroxyl radical assay, superoxide radical assay, and DPPH radical assay, its antioxidant activities were investigated. PBF3 had significant effect on scavenging hydroxyl radicals, an equivalent inhibiting ability to vitamin C on superoxide radical, and a little lower scavenging activity on DPPH radical than vitamin C, and should be explored as a novel potential antioxidant.

Shape Optimization Method of Free-form Cable-braced Grid Shells Based on the Translational Surfaces Technique

Ruo-qiang Feng,Jin-ming Ge 한국강구조학회 2013 International Journal of Steel Structures Vol.13 No.3

Cable-braced grid shells, being a new type of single-layer reticulated shell, are widely used in glass roofs. However, research on the shape optimization of free-form cable-braced grid shells is relatively lacking. This paper describes a shape optimization method for cable-braced free-form grid shells, with strain energy used as the optimization object, structural height used as the optimization variable, and the conjugate gradient method used as the optimization algorithm. According to the shape forming method for grid shells, their shape optimization can be realized only by adjusting the generatrix and directrix, not by optimizing the whole surface. The B-spline curve method is used to model the generatrix and directrix and maintain an optimized surface fairing. The following conclusions can be drawn from this study. First, the structural mechanical behavior of grid shells can be significantly improved with rapid convergence using the proposed shape optimization method. Second, the plane quadrilateral mesh is maintained and fewer optimization variables are needed during the proposed shape optimization method. Finally, the optimized surface is fairing and the mechanical properties of the optimized surface are somewhat decreased when using the B-spline curve method.

Multi-objective Morphology Optimization of Free-form Cable-braced Grid Shells

Ruo-qiang Feng,linlin Zhang,Jin-ming Ge 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.3

This paper examines the multi-objective morphology optimization of free-form cable-braced grid shells. First, according to the shape forming method for grid shells, shape optimization can be realized by adjusting the generatrix and directrix rather than optimizing the whole surface. Second, the multi-objective shape optimization of free-form cable-braced grid shells is conducted. According to different practical requirements, the mechanical and geometric indexes, mechanical and economic indexes, or different mechanical indexes are used as multiple optimization objectives. Four main conclusions can be drawn from this study. First, with the above shape optimization method, the optimized surface does not change significantly; therefore, this method is useful in the shape optimization of grid shells with given initial surfaces. Second, among the static mechanical performance indexes, the mechanical behavior of the cable-braced grid shell is better with strain energy as the optimization objective. Third, with the weight of steel tubes and strain energy as the optimization objectives, the result of the multi-objective optimization that combines section optimization with shape optimization is favorable and practical in engineering applications. Fourth, when strain energy and the variance of the tube lengths are used as multiple optimization objectives, the structural mechanical behavior is not sensitive to the weight factor of variance of the tube lengths.

Optimization of the Field Shaper Parameters in Electromagnetic Pulse Crimping of Cable

Fen-Qiang Li,Jishuai Jiang,Hongsong Cheng,Jianling Xu,Xiaohong Ge,Hui Li,Jun Zhao,Yang Ran 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.10

Crimping of wires to achieve a secure connection is one of the most critical challenges in fabrication of electronic circuit boards, automobiles, aviation, satellite and communication components. The electromagnetic pulse crimping process offers great potential to successfully address these challenges. In this paper, ANSYS/Multi physical software was used to first determine the electromagnetic force distribution on the terminal lug by analyzing the magnetic field in the electromagnetic pulse crimping process. The electromagnetic force was then imported into the ABAQUS/Explicit software as the boundary condition to calculate the deformation behavior of the terminal lug barrel and cable according to the stress–strain curve of the terminal material under high strain rate. The calculated deformation result was subsequently verified by experimental data. Three main parameters of the field shaper were analyzed to determine their influence on the crimping result; slit position, the inner diameter vertical dimension and the position relationship between the terminal lug and field shaper. Then using the empirical formula we calculated and verified the inner diameter vertical dimension of the field shaper. The model proved to be reliable. Deformation of the terminal was determined to be uneven along the circumference in the crimping area. For the type of terminal lug studied, an inner diameter vertical dimension of 10 mm proved to be optimum for increased strength of the crimped terminal connection. Allowing the terminal to protrude 1 mm from the field shaper resulted in a flatter crimped area and significant improvement in the quality of the crimped barrel surface. The empirical formula for calculating the inner diameter vertical dimension of the field shaper is reasonable and reliable, and the calculated measurement resulted in improved connection strength. The results of this research can be used to guide the electromagnetic pulse crimping of other terminal lug and cable types.

Rejection rate and mechanisms of drugs in drinking water by nanofiltration technology

Sijie Ge,Li Feng,Liqiu Zhang,Qiang Xu,Yifei Yang,Ziyuan Wang,Ki-Hyun Kim 대한환경공학회 2017 Environmental Engineering Research Vol.22 No.3

Nanofiltration (NF) technology is a membrane-based separation process, which has been pervasively used as the high-effective technology for drinking water treatment. In this study, a kind of composite polyamide NF thin film is selected to investigate the removal efficiencies and mechanisms of 14 trace drugs, which are commonly and frequently detected in the drinking water. The results show that the removal efficiencies of most drugs are quite high, indicating the NF is an effective technology to improve the quality of drinking water. The removal efficiencies of carbamazepine, acetaminophen, estradiol, antipyrine and isopropyl-antipyrine in ultrapure water are 78.8 ± 0.8%, 16.4 ± 0.5%, 65.4 ± 1.8%, 71.1 ± 1.5% and 89.8 ± 0.38%, respectively. Their rejection rates increase with the increasing of their three-dimensional sizes, which indicates that the steric exclusion plays a significant role in removal of these five drugs. The adsorption of estradiol with the strongest hydrophobicity has been studied, which indicates that adsorption is not negligible in terms of removing this kind of hydrophobic neutral drugs by NF technology. The removal efficiencies of indomethacin, diclofenac, naproxen, ketoprofen, ibuprofen, clofibric acid, sulfamethoxazole, amoxicillin and bezafibrate in ultrapure water are 81 ± 0.3%, 86.3 ± 0.5%, 85.7 ± 0.4%, 93.3 ± 0.3%, 86.6 ± 2.5%, 90.6 ± 0.4%, 59.7 ± 1.7%, 80.3 ± 1.4% and 80 ± 0.5%, respectively. For these nine drugs, their rejection rates are better than the above five drugs because they are negatively charged in ultrapure water. Meanwhile, the membrane surface presents the negative charge. Therefore, both electrostatic repulsion and steric exclusion are indispensable in removing these negatively charged drugs. This study provides helpful and scientific support of a highly effective water treatment method for removing drugs pollutants from drinking water.

Study on the Mechanical Characteristics of Urban Sludge Solidified by Industrial Waste

Liuyan Wu,Qiang Wang,Dandan Ge,Huangrui Xu,Guojun Cai 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.7

Urban sludge is an extensive volume with a prominent environmental impact. The researchexplored an application technology for converting urban sludge into a usable improved soilresource by using industrial waste, providing a new reference for the reuse of industrial waste. In this study, three industrial wastes, namely ground granulated blast slag, calcium carbideresidue, and desulfurized gypsum, were used as curing agents to solidify the urban sludge. Based on the unconfined compressive strength (UCS) test and chamber analysis, the effects ofcuring agent dosing and maintenance age of sludge-cured soil on the UCS and stress- strainwere studied. The results showed that with the increase of curing agent, the UCS of cured soilfirst increased and then decreased, and the breaking strain showed a decreasing trend. Theoptimum ratio of materials was sludge: calcium carbide residue: ground granulated blast slag:desulfurization gypsum = 100:15:15:5, record this material ratio as C15G15D5. Moreover,trials showed that C15G15D5 cured the sludge soil better than the cement alone, whichachieved the purpose of reusing the three industrial wastes and urban sludge. It was analyzedthat the hydrated calcium silicate (C-S-H), calcium aluminate (C-A-H) and ettringite (AFt) inthe hydration products were produced to make the soil skeleton stronger and enhance thestrength of the sludge-cured soil.