Effect of SiO2 Aerogel on the Properties of Inorganic Cementing Materials

Yunan Wan,Jianhong Wang,Zhiyong Li 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.8

SiO2 aerogel powder has ultralow weight and thermal conductivity, and it cannot be easily dispersed in inorganic cementing materials (i.e., it is incompatible with inorganic cementing materials). In this study, the properties of inorganic cementing materials with hemihydrate gypsum and α-hemihydrate gypsum as main cementing materials were investigated. Moreover, the property changes resulting from the addition of SiO2 aerogel to inorganic cementing materials were examined. Based on the obtained results, the composites of SiO2aerogel and inorganic cementing materials with optimal properties were prepared and investigated. The results revealed that when the composition mass ratio of the inorganic cementing material was 1:3:9:0.8 (fly ash:cement:hemihydrate gypsum:lime), the compressive strength of the cementing material was largest, reaching 7.71 MPa after 28 days of curing. Moreover, when the composition mass ratio of the inorganic cementing material was 1:3:9:0.4/0.6 (fly ash:cement:hemihydrate gypsum:lime), its softening coefficient was highest, reaching 0.97. Under the same mass ratio, the 28-day compressive strength of the α-hemihydrate gypsum-based cementing material was 2.4 times that of the plaster-based cementing material. When the SiO2 aerogel was added to the gypsum-based composite cementing material, the compressive strength and softening coefficient decreased with increasing SiO2 aerogel’s content.

Experimental study and prediction model of the cleaning effect induced by self-resonating cavitating waterjet

Yunan Yao,Hua Wang,Zhenlong Fang,Deng Li,Bin Wang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.10

Self-resonating cavitation waterjet (SRCW) has rapidly developed and been widely used in cleaning fields due to its non-thermal and environmentally friendly machining. However, its fuzzy relationship between cleaning effect and working parameters is a significant limit to cleaning quality improving and extensive application of SRCW. Addressing this issue, an evaluation method of cleaning effect induced by SRCW was proposed in this paper, which includes two evaluation parameters, cleaning rate (R c , mm 2 /s) and primer damage rate (R d ). Using this method, experiments on the effects of four working parameters (pressure, traverse rate, standoff distance and impact angle) on the cleaning effect were carried out, and the results showed that R c and R d is proportional to pressure, with the decrease of attacking angle or the increase of traverse rate and standoff distance, R d always decreases while R c increases first and then decreases. A prediction model of SRCW cleaning effect considering pressure, traverse rate, standoff distance and impact angle was established with the use of GA-BP neural network. The prediction results indicate that the model has better adaptive ability and high prediction accuracy of over 95 %. And according to the prediction and different optimization objectives, the working parameters of SRCW were obtained. The study provided a new method to evaluate the cleaning effect of SRCW, and the working parameters were predicted and optimized by reliably modeling, which is of great significance to guide the practical application of SRCW.

Matching theory for future wireless networks: fundamentals and applications

Yunan Gu,Saad, Walid,Bennis, Mehdi,Debbah, Merouane,Zhu Han Institute of Electrical and Electronics Engineers 2015 IEEE communications magazine Vol.53 No.5

<P>The emergence of novel wireless networking paradigms such as small cell and cognitive radio networks has forever transformed the way in which wireless systems are operated. In particular, the need for self-organizing solutions to manage the scarce spectral resources has become a prevalent theme in many emerging wireless systems. In this article, the first comprehensive tutorial on the use of matching theory, a Nobel Prize winning framework, for resource management in wireless networks is developed. To cater for the unique features of emerging wireless networks, a novel, wireless-oriented classification of matching theory is proposed. Then the key solution concepts and algorithmic implementations of this framework are exposed. The developed concepts are applied in three important wireless networking areas in order to demonstrate the usefulness of this analytical tool. Results show how matching theory can effectively improve the performance of resource allocation in all three applications discussed.</P>

A Novel Face Template Protection Algorithm Based on the Fusion of Chaos Theory and RSA Encryption

Liu Yunan,Zhao Fudong,Xu Yanli,Cao Yu 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.6

In the face recognition system, the protection of the facial feature template has already become the most important part. In view of that the current protection methods cannot meet the security and the matching rate simultaneously, a hybrid encryption algorithm was proposed in this paper fusing chaotic encryption and RSA encryption to solve this problem. After the preprocessing to the ORL face database, the feature template was extracted by 2D2LDA and PCA in the non-transformation domain. Then we applied the scrambling encryption and RSA encryption to obtain the final security template. At last, a system with the nearest neighbor classifier and Euclidean distance was used for the matching verification. The experimental results showed that this hybrid encryption method was feasible, effective and easy transplantation with no matching rate reduction.

Upcycling the Spent Mushroom Substrate of the Grey Oyster Mushroom Pleurotus pulmonarius as a Source of Lignocellulolytic Enzymes for Palm Oil Mill Effluent Hydrolysis

( Nurul Anisa Mat Yunan ),( Tan Yee Shin ),( Vikineswary Sabaratnam ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.6

Mushroom cultivation along with the palm oil industry in Malaysia have contributed to large volumes of accumulated lignocellulosic residues that cause serious environmental pollution when these agroresidues are burned. In this study, we illustrated the utilization of lignocellulolytic enzymes from the spent mushroom substrate of Pleurotus pulmonarius for the hydrolysis of palm oil mill effluent (POME). The hydrolysate was used for the production of biohydrogen gas and enzyme assays were carried out to determine the productivities/activities of lignin peroxidase, laccase, xylanase, endoglucanase and β-glucosidase in spent mushroom substrate. Further, the enzyme cocktails were concentrated for the hydrolysis of POME. Central composite design of response surface methodology was performed to examine the effects of enzyme loading, incubation time and pH on the reducing sugar yield. Productivities of the enzymes for xylanase, laccase, endoglucanase, lignin peroxidase and β-glucosidase were 2.3, 4.1, 14.6, 214.1, and 915.4 U g^-1, respectively. A maximum of 3.75 g/l of reducing sugar was obtained under optimized conditions of 15 h incubation time with 10% enzyme loading (v/v) at a pH of 4.8, which was consistent with the predicted reducing sugar concentration (3.76 g/l). The biohydrogen cumulative volume (302.78 ml H₂.L^-1 POME) and 83.52% biohydrogen gas were recorded using batch fermentation which indicated that the enzymes of spent mushroom substrate can be utilized for hydrolysis of POME.

Multi-Dimensional Incentive Mechanism in Mobile Crowdsourcing with Moral Hazard

Zhang, Yanru,Gu, Yunan,Pan, Miao,Tran, Nguyen H.,Dawy, Zaher,Han, Zhu IEEE 2018 IEEE transactions on mobile computing Vol.17 No.3

<P>In current wireless communication systems, there is a rapid development of location based services, which will play an essential role in the future 5G networks. One key feature in providing the service is the mobile crowdsourcing in which a central cloud node denoted as the principal collects location based data from a large group of users. In this paper, we investigate the problem of how to provide continuous incentives based on user’s performances to encourage users’ participation in the crowdsourcing, which can be referred to the moral hazard problem in the contract theory. We not only propose the one-dimensional performance-reward related contract, but also extend this basic model into the multi-dimensional contract. First, an incentive contract which rewards users by evaluating their performances from multiple dimensions is proposed. Then, the utility maximization problem of the principal in both one-dimension and multi-dimension are formulated. Furthermore, we detailed the analysis of the multi-dimensional contract to allocate incentives. Finally, we use the numerical results to analyze the optimal reward package, and compare the principal’s utility under the different incentive mechanisms. Results demonstrate that by using the proposed incentive mechanism, the principal successfully maximizes the utilities, and the users obtain continuous incentives to participate in the crowdsourcing activity.</P>

GASIFICATION OF UNSYMMETRICAL DIMETHYLHYDRAZINE IN SUPERCRITICAL WATER

Lei Yi,Liejin Guo,Yunan Chen,Hui Jin 한국신재생에너지학회 2015 AFORE Vol.2015 No.11

Solution and Estimate to the Angular Velocity of INS Formed only by Linear Accelerometers

Wu Junwei,Liu Jinfeng,Zhang Yunan,Yuan Na 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.1 No.-

At present, most efforts tend to develop a INS which is only based linear accelerometers, because of the low cost micro-machining gyroscopes lack of the accuracy needed for precise navigation application and possible achieving the required levels of precise for micro-machining accelerometer. Although it was known in theory that a minimum of six accelerometers are required for a complete description of a rigid body motion, and any configuration of six accelerometers (except for a “measure zero” set of six-accelero-meter schemes) will work. Studies on the feasible configuration of GF-INS indicate that the errors of angular velocity resolved from the six accelerometers scheme are diverged with time or have multi solutions. The angular velocity errors are induced by the biases together with the position vectors of the accelerometers, therefore, in order to treat with the problem just mentioned, researchers have been doing many efforts, such as the extra three accelerometers or the magnetometers may be taken as the reference information, the extended Kalman filter (EKF) involved to make the angular velocity errors bound and be estimated, and so on. In this paper, the typical configurations of GF-INS are introduced; for each type GF-INS described, the solutions to the angular velocity and the specific force are derived and the characteristic is indicated; one of the corresponding extend Kalman filters are introduced to estimate the angular errors; parts of the simulation results are presented to verify the validity of the equations of angular velocity and specific force and the performance of extend Kalman filter.

Extraction of Pigment from Sugarcane Juice Alcohol Wastewater and Evaluation of Its Antioxidant and Free Radical Scavenging Activities

Jingbo Li,Lei Liang,Jingrong Cheng,Yunan Huang,Ming-Jun Zhu,Shizhong Liang 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.5

Pigment was extracted to decolor the sugarcane juice alcohol wastewater and its antioxidant activities were evaluated. The pigment was extracted using ion exchange fiber along with macroporous resin D-101 as the absorbent and an ethanol-water mixture (6:4, v/v) as the eluent. Total flavonoid and phenolic contents of the pigment were determined. DPPH radical scavenging ability and reducing power of 1.0 mg/mL of the pigment were approximately 78.5 and 16.8%, respectively, compared to 1.0 mg/mL of the tea polyphenol (positive control). The hydroxyl radical scavenging ability of 10.0 mg/mL of the pigment was about 92.5% compared to that of positive control. The DPPH radical scavenging ability of the pigment was enhanced significantly with thermal treatment at 70 and 100oC. The result shows the proposed procedure can be effective to decolor such wastewater and to get antioxidative pigment.

Target engagement of ginsenosides in mild cognitive impairment using mass spectrometry-based drug affinity responsive target stability

Zhu, Zhu,Li, Ruimei,Qin, Wei,Zhang, Hantao,Cheng, Yao,Chen, Feiyan,Chen, Cuihua,Chen, Lin,Zhao, Yunan The Korean Society of Ginseng 2022 Journal of Ginseng Research Vol.46 No.6

Background: Mild cognitive impairment (MCI) is a transitional condition between normality and dementia. Ginseng is known to have effects on attenuating cognitive deficits in neurogenerative diseases. Ginsenosides are the main bioactive component of ginseng, and their protein targets have not been fully understood. Furthermore, no thorough analysis is reported in ginsenoside-related protein targets in MCI. Methods: The candidate protein targets of ginsenosides in brain tissues were identified by drug affinity responsive target stability (DARTS) coupled with label-free liquid chromatography-mass spectrometry (LC-MS) analysis. Network pharmacology approach was used to collect the therapeutic targets for MCI. Based on the above-mentioned overlapping targets, we built up a proteineprotein interaction (PPI) network in STRING database and conducted gene ontology (GO) enrichment analysis. Finally, we assessed the effects of ginseng total saponins (GTS) and different ginsenosides on mitochondrial function by measuring the activity of the mitochondrial respiratory chain complex and performing molecular docking. Results: We screened 2526 MCI-related protein targets by databases and 349 ginsenoside-related protein targets by DARTS. On the basis of these 81 overlapping genes, enrichment analysis showed the mitochondria played an important role in GTS-mediated MCI pharmacological process. Mitochondrial function analysis showed GTS, protopanaxatriol (PPT), and Rd increased the activities of complex I in a dose-dependent manner. Molecular docking also predicted the docking pockets between PPT or Rd and mitochondrial respiratory chain complex I. Conclusion: This study indicated that ginsenosides might alleviate MCI by targeting respiratory chain complex I and regulating mitochondrial function, supporting ginseng's therapeutic application in cognitive deficits.