Extraction of chitin from white shrimp (Penaeus vannamei) shells using binary ionic liquid mixtures

Qiqi Dong,Weiqiang Qiu,Li Li,Ningping Tao,Ashley Liang Wang,Shanggui Deng,Yinzhe Jin 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.120 No.-

Binary ionic liquid mixtures (IL) were used for the first time to extract chitin from shrimp shells. Twoionic liquids, 1-ethyl-3-methylimidazole acetate ([EMIM][Ac]) and 1-butyl-3-methylimidazole bromidesalt ([BMIM][Br]), were mixed at ratios of 0:1, 1:1, 3:2, 4:1, and 1:0 and the properties of the IL andthe characteristics of extracted chitin were investigated. With an increase in proportion of [EMIM][Ac],the viscosity, dielectric constant, and dielectric loss of IL gradually decreased (p < 0.05), whereas the conductivity,radius of gyration increased (p < 0.05). The best quality of chitin using IL (3:2) was achievedwhen the viscosity, conductivity, and radius of gyration were 0.16 ± 0.00 Pa s, 0.30 ± 0.01 S/m, and 0.10 ± 0.00 nm, respectively. The yield of chitin extraction using IL was 35.72 ± 0.31 %, and this was approximately2.04 times higher than that using the acid-base method (17.50 ± 0.16 %). The Whiteness index(WI) of chitin extracted using IL (3:2) (94.93 ± 0.09) was better than commercial chitin (93.31 ± 0.11),and the secondary structure, surface morphology and thermal stability were similar to commercial chitin. Therefore, the binary ionic liquid mixture can be used as an effective green solvent to extract chitin fromshrimp shells.

Apple residues derived porous carbon nanosheets synthesized with FeCl3 assisted hydrothermal carbonization for supercapacitors with high rate performance

Li Qiqi,Zhang Yingnan,Song Ya,Yang Huawei,Yang Lixia,Bai Liangjiu,Wei Donglei,Wang Wenxiang,Liang Ying,Chen Hou 한국탄소학회 2023 Carbon Letters Vol.33 No.2

Biomass carbon materials with high rate capacity have great potential to boost supercapacitors with cost effective, fast charging–discharging performance and high safety requirements, yet currently suffers from a lack of targeted preparation methods. Here we propose a facile FeCl3 assisted hydrothermal carbonization strategy to prepare ultra-high rate biomass carbon from apple residues (ARs). In the preparation process, ARs were first hydrothermally carbonized into a porous precursor which embedded by Fe species, and then synchronously graphitized and activated to form biocarbon with a large special surface area (2159.3 m2 g−1) and high degree of graphitization. The material exhibited a considerable specific capacitance of 297.5 F g−1 at 0.5 A g−1 and outstanding capacitance retention of 85.7% at 10 A g−1 in 6 M KOH, and moreover, achieved an energy density of 16.2 Wh kg−1 with the power density of 350.3 W kg−1. After 8000 cycles, an initial capacitance of 95.2% was maintained. Our findings provide a new idea for boosting the rate capacity of carbon-based electrode materials.

Study on preparation of inorganic binder stabilized material with large dosage of phosphogypsum

Sun Qiqi,Tao Liangjing,Li Xin,Xu Wei,Yao Shuo,Li Jinpeng,Ren Qi-Fang,Chen Yue’e,Xu Chunshan,Wu Zilong,Zhu Yuelei,Ding Yi,오원춘 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.6

With the rapid development of the phosphorus chemical industry, a large amount of phosphogypsum (PG) is discharged. The impurities in PG pollute the surrounding soil, the groundwater and the air in the long-term storage. In this paper, PG as the main raw material is used to study the stable material of inorganic binder in the condition of large dosage of PG. With PG and graded gravel as stabilized materials, and cement and fly ash as binder, materials are mixed to determine the influence of PG ratio and the amount of activator on the mixture. The results show that the mechanical strength of the mixture increased first and then decreased with the increase in the proportion of PG replacing graded gravel in the mixture. The activator significantly improves the properties of the material system and makes a significant contribution to the curing of PG. The best ratio of pretreated PG: cement: fly ash: aggregate is 50:6:5:39. The amount of activator added by the external mixing method is 0.3%, which can make the unconfined compressive strength reach 4.1 MPa after 7d. Finally, water-soluble phosphorus leaching experiment is conducted for all the samples. The results show that phosphorus leaching is so little that no secondary pollution of the environment is caused.

Experimental and Numerical Study on Response Characteristics of Airport Pavement Subjected to Wetting in Silt Subgrade

Qiqi Luo,Xinyu Ye,Qiang Li,Sheng Zhang,Qian Yu,Xinyan Ma 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.2

Silt is often selected as the filling soil in Northwest and North China. “Pot cover effect” or rainfall infiltration are easily to cause localized wetting during the service period of airport. The response characteristics of pavement derived from aircraft loading under wetting condition are the basis to explore the evolution law of pavement damage. To investigate this response characteristics for different parameters of pavement under wetting condition, a self-developed model test system was developed, and the verified numerical model was then established. The interaction mechanisms of pavement slabs, and the influence of wetting on mechanical response in loading area of pavement under different pavement parameters were analyzed. The results showed that the increased vertical deformation depends on water-holding capacity of silt, and the vertical deformation under loading is little affected by pavement parameters. The peak shear stress and the increased peak shear stress derived from wetting at the bottom of pavement layers are largely influenced by elastic modulus of base course. For cement concrete pavement, the increase in load transfer capacity of joints cannot decrease the increase of peak stress, including horizontal stress and shear stress, derived from wetting. The increase in load transfer capacity of joints can decrease the stress concentration in surface layer, while the elastic modulus of surface layer has little influence. For bituminous pavement, optimal parameters of base course can be obtained to decrease the peak stress and the increase of peak stress derived from wetting in subgrade. The research can provide technical basis for the structure design, optimization, and disease treatment of pavement in airport engineering.

Experimental and Numerical Investigation of Local Scour for Suspended Square Caisson under Steady Flow

Qiqi Xiang,Kai Wei,Yadong Li,Mingjin Zhang,Shunquan Qin 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.9

A caisson can be suspended in the river during its settlement construction. The water flows induces the local scour of sediments under the caisson, which increases the settlement difficulty and threatens the safety of construction. A numerical model using computational fluid dynamics (CFD) was introduced to simulate the local scour process around the caisson. The numerical model was validated with a set of experimental tests, which were conducted to investigate the local scour for a square caisson model with different clearances under steady flow. The evolutions and characteristics of local scour pits as a function of clearance were investigated based on the experimental and numerical results. The effect of grain size of sediment and the scour mechanism for suspended caisson were discussed as well. The main findings include: 1) the minimum inflow velocity for the scour of sediment depends on the clearance between the caisson bottom and sediment; 2) the numerical model provides reasonable evolution of local scour pit and flow field around the caisson; and 3) the scour depth of suspended caisson can be as high as 70% of that for the settled caisson and deserves attention for the safe settlement of caisson.

HTSC and FH_HTSC: XOR-based Codes to Reduce Access Latency in Distributed Storage Systems

Qiqi Shuai,Victor O. K. Li 한국통신학회 2015 Journal of communications and networks Vol.17 No.6

A massive distributed storage system is the foundation for big data operations. Access latency performance is a key metric in distributed storage systems since it greatly impacts user experience while existing codes mainly focus on improving performance such as storage overhead and repair cost. By generating parity nodes from parity nodes, in this paper we design new XORbased erasure codes hierarchical tree structure code (HTSC) and high failure tolerant HTSC (FH HTSC) to reduce access latency in distributed storage systems. By comparing with other popular and representative codes, we show that, under the same repair cost, HTSC and FH HTSC codes can reduce access latency while maintaining favorable performance in other metrics. In particular, under the same repair cost, FH HTSC can achieve lower access latency, higher or equal failure tolerance and lower computation cost compared with the representative codes while enjoying similar storage overhead. Accordingly, FH HTSC is a superior choice for applications requiring low access latency and outstanding failure tolerance capability at the same time.

Phylogeography of walnut pest Atrijuglans hetaohei (Lepidoptera: Gelechioidea) reveals comprehensive influence of geographic barriers and human activities

Qiqi Wang,Shaheen Tayyab,Rong Li,Guanghui Tang 한국응용곤충학회 2022 Journal of Asia-Pacific Entomology Vol.25 No.3

Phylogeographic patterns of some extant species have been well documented; however, the evolutionary patterns of plant pests were poorly understood. This study investigated the evolutionary patterns and historical demog raphy of Atrijuglans hetaohei using mitochondrial DNA (cox1 and cox2) and nuclear EF-1α. Networks and other statistical analyses concordantly revealed four genetic lineages (L1-L4), indicating varying influences of moun tains and rivers. Two shared ancestral haplotypes and strong gene flow in refugia (Mt. Qinling and Daba Shan) indicated that the evolutionary patterns of A. hetaohei coincided with its plant hosts, and A. hetaohei experienced long-term vicariance and secondary contact in these areas. The demographic analysis (EBSP) clearly showed that A. hetaohei underwent two sustained population expansions 4000 years ago, and its population size was affected by the size and quality of its plant hosts resulting from human agricultural activities. All the evidence suggests that physical barriers (mountains and rivers) and human agricultural activities have affected this insect’s pop ulation structure and distribution to varying degrees. Together, our study contributes to a growing understanding of the origin and population structure of A. hetaohei and provides an important framework for exploring the evolution patterns of the pest and its hosts.

20(S)- Protopanaxadiol suppresses hepatic stellate cell activation via WIF1 demethylation-mediated inactivation of the Wnt/β-catenin pathway

Chunxue Li,Yating Zhan,Rongrong Zhang,Qiqi Tao,Zhichao Lang,Jianjian Zheng 고려인삼학회 2023 Journal of Ginseng Research Vol.47 No.4

Enhanced thermoelectric performance of Cu3SbSe4 doped with alkali-ion (Na and K)

Yunchen Dou,Qiqi Zhu,Yong Du,Jiayue Xu,Di Li 대한금속·재료학회 2020 ELECTRONIC MATERIALS LETTERS Vol.16 No.2

The thermoelectric properties of alkali-ion-doped compounds Cu 3 Sb 1− x M x Se 4 (M = Na and K) prepared by mechanicalalloying and spark plasma sintering compaction, are investigated systematically between 300 K and 673 K. The increase inthe hole carrier concentration causes a reduction in the electrical resistivity in the whole temperature range and a rise in thepower factor at elevated temperature for alkali-ion-doped compounds as compared to pristine Cu 3 SbSe 4 . For example, themaximum power factors for Cu 3 Sb 1− x Na x Se 4 ( x = 0.02 and 0.03) and Cu 3 Sb 0.99 K 0.01 Se 4 at 673 K are all increased by around1.6 times compared to the un-doped sample. As a result, the peak ZT value reaches 0.52 and 0.71 at 673 K for Cu 3 Sb 1− x Na x Se 4( x = 0.02 and 0.03) and Cu 3 Sb 0.99 K 0.01 Se 4 , which is 27% and 73% larger than that (0.41) of the un-doped sample, respectively. In this work, K-doping is more eff ective in improving thermoelectric performance of Cu 3 SbSe 4 , due to its larger ionic radius,which can bring more lattice distortions and point defects to scatter phonons than Na-doping.

Application Research on Mechanical Strength and Durability of Porous Basalt Concrete

Zhu, Yuelei,Li, Jingchun,Zhu, He,Jin, Long,Ren, Qifang,Ding, Yi,Li, Jinpeng,Sun, Qiqi,Wu, Zilong,Ma, Rui,Oh, Won-Chun Materials Research Society of Korea 2022 한국재료학회지 Vol.32 No.3

Porous basalt aggregate is commonly used in roadbed engineering, but its application in concrete has rarely been studied. This paper studies the application of porous basalt in concrete. Porous basalt aggregate is assessed for its effects on mechanical strength and durability of prepared C50 concrete; because it has a hole structure, porous basalt aggregate is known for its porosity, and porous basalt aggregates can be made full of water through changing the content of saturated basalt; after full-water condition is achieved in porous basalt aggregate mixture of C50 concrete, we discuss its mechanical properties and durability. The effects of C50 concrete prepared with basalt aggregate on the compressive strength, water absorption, and electric flux of concrete specimens of different ages were studied through experiments, and the effects of different replacement rates of saturated porous basalt aggregate on the properties of concrete were also studied. The results show that porous basalt aggregate can be prepared as C50 concrete. For early saturated porous basalt aggregate concrete, its compressive strength decreases with the increase of the replacement rate of saturated aggregate; this occurs up to concrete curing at 28 d, when the replacement rate of saturated basalt aggregate is greater than or equal to 40 %. The compressive strength of concrete increases with the increase of the replacement rate of saturated aggregate. The 28 d electric flux decreases with the increase of the replacement rate of saturated aggregate, indicating that saturated porous basalt aggregate can improve the chloride ion permeability resistance of concrete in later stages.