Development of Plastic/Gelatin Bilayer Active Packaging Film with Antibacterial and Water-Absorbing Functions for Lamb Preservation

Shijing Wang,Weili Rao,Chengli Hou,Raheel Suleman,Zhisheng Zhang,Xiaoyu Chai,Hanxue Tian 한국축산식품학회 2023 한국축산식품학회지 Vol.43 No.6

In order to extend the shelf life of refrigerating raw lamb by inhibiting the growth of microorganisms, preventing the oxidation of fat and protein, and absorbing the juice outflow of lamb during storage, an active packaging system based on plastic/gelatin bilayer film with essential oil was developed in this study. Three kinds of petroleumderived plastic films, oriented polypropylene (OPP), polyethylene terephthalate, and polyethylene, were coated with gelatin to make bilayer films for lamb preservation. The results showed significant improvement in the mechanical properties, oxygen, moisture, and light barriers of the bilayer films compared to the gelatin film. The OPP/gelatin bilayer film was selected for further experiments because of its highest acceptance by panelists. If the amount of juice outflow was less than 350% of the mass of the gelatin layer, it was difficult for the gelatin film to separate from lamb. With the increase in essential oil concentration, the water absorption capacity decreased. The OPP/gelatin bilayer films with 20% mustard or 10% oregano essential oils inhibited the growth of bacteria in lamb and displayed better mechanical properties. Essential oil decreased the brightness and light transmittance of the bilayer films and made the film yellow. In conclusion, our results suggested that the active packaging system based on OPP/gelatin bilayer film was more suitable for raw lamb preservation than single-layer gelatin film or petroleum-derived plastic film, but need further study, including minimizing the amount of essential oil, enhancing the mechanical strength of the gelatin film after water absorption.

Enhanced photocatalytic activity over ZnO supported on calcium sulfate whisker derived from desulfurization gypsum

Shijing Lin,Yu Tian,Wei Zhang,Tiantian Zhao,Mingxin Zhao,Hong Wang 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.12

Calcium sulfate whisker (CSW) was prepared from flue gas desulfurization (FGD) gypsum by recrystallizationmethod, and then was employed in preparing ZnO/CSW photocatalysts by impregnation method. CSW andZnO/CSW were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Xraydiffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), UVVisdiffuse reflectance spectroscopy (UV-Vis DRS) and photoluminescence spectrum (PL). The photocatalytic activityof various ZnO/CSW photocatalysts was evaluated by photocatalytic degradation of methylene blue (MB) under simulatedsunlight irradiation. The results showed that various ZnO/CSW photocatalysts exhibited much higher photocatalyticactivity than pure ZnO and CSW. Among various ZnO/CSW photocatalysts, the photocatlytic activity of ZnO/CSW increased as increasing the ZnO loading amount from 1.2% to 8.7%, but decreased when the ZnO loadingamount was beyond 8.7% due to the increasing crystalline size of ZnO and recombination of photogenerated hole/electronpairs. Besides ZnO loading amount, MB initial concentration and the dosage of photocatalyst also had significantinfluence on MB degradation rate, and MB degradation rate over ZnO/CSW reached 95.4% under optimum conditions. Kinetics study revealed that the photocatalytic degradation of MB over ZnO/CSW can be described by thepseudo-first-order kinetic model, and the apparent rate constant k versus ZnO loading amount L, MB initial concentrationC0 and the dosage of photocatalyst D can be described as: k=0.5237L0.5193C00.3074D0.4589.

An Acid-/Base-Degradable Epoxy Resin Cured by 1,3,5-Triacroylamino- hexahydro-s-triazine Derivative

Lei Wang,Shijing Yan,Lei Zhang,Yuliang Mai,Weihao Li,Hao Pang 한국고분자학회 2021 Macromolecular Research Vol.29 No.7

The degradation and recycling of waste epoxy resin products is an urgent environmental problem. To solve this issue, we use acid-/base-degradable 1,1’,1"- (1,3,5-hexahydro-s-triazine-1,3,5-triyl) tris(3-ethylamino-propan-1-one) (TAHT-EA) as curing agent to introduce the hexahydro-s-triazine (HT) ring structure into the cross-linking network to prepare degradable epoxy resin. Specifically, 1,3,5-triacryloylhexahydro- 1,3,5-triazine (TAHT) and ethylamine quickly complete the Aza-Michael addition reaction at the interface of chloroform and water droplets under the catalysis of water. The FTIR spectra, NMR spectrum and mass spectrum show that mono- and bis-addition products of ethylamine coexist in the product in which the content of the primary addition product reaches 97%. TAHT-EA can be decomposed by acid and base solutions. Through NMR analysis of the degradation products, it can be explained that the degradation mechanisms are different. The breaking of amide bonds and HT rings in acid solution and the cracking of amide bonds in base solution are speculated to be the main mechanisms under these two different circumstances, respectively. We tested the mechanical, thermal and degradation properties of the epoxy resin cured by TAHT-EA, and compared it with the epoxy resin cured by 4,4'-diaminodiphenylmethane and triethylenetetramine. TAHT-EA-cured epoxy resin shows comparable mechanical properties with Young’s modulus up to 2.05 GPa and tensile strength up to 70.9 MPa. What is more, it degrades completely by 1 M H+/OH- solution at 60℃ within 36 h. Nevertheless, it exhibited a relatively low crosslinked density (633 mol/m3) and low heat resistance (the initial decomposition temperature is lower than 205℃). Overall, TAHT-EA cured epoxy resin has the potential to gradually replace traditional thermosetting resin, thereby solving the environmental problems caused by discarded epoxy resin products.

Building Change Detection Using Deep Learning for Remote Sensing Images

Chang Wang,Shijing Han,Wen Zhang,Shufeng Miao 한국정보처리학회 2022 Journal of information processing systems Vol.18 No.4

To increase building change recognition accuracy, we present a deep learning-based building change detection using remote sensing images. In the proposed approach, by merging pixel-level and object-level information of multitemporal remote sensing images, we create the difference image (DI), and the frequency-domain significance technique is used to generate the DI saliency map. The fuzzy C-means clustering technique preclassifies the coarse change detection map by defining the DI saliency map threshold. We then extract the neighborhood features of the unchanged pixels and the changed (buildings) from pixel-level and object-level feature images, which are then used as valid deep neural network (DNN) training samples. The trained DNNs are then utilized to identify changes in DI. The suggested strategy was evaluated and compared to current detection methods using two datasets. The results suggest that our proposed technique can detect more building change information and improve change detection accuracy.

Novel frictional algorithm implementing angular increment for two-dimensional frictional systems

Deng Zhao,Shijing Wu,Qiaoquan Li,Xiaofeng Li,Xiaoyong Li,Xiaosun Wang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.7

This study proposes a new frictional algorithm that implements angular increment. The proposed algorithm is used to solve the numerical solutions of dynamic problems in two-dimensional frictional systems. It can accurately obtain the motion responses of a lumped mass under time-varying external forces, and it can compensate for the shortcomings of the numerical frictional algorithm that implements a time step. Specifically, the proposed algorithm 1) overcomes the difficulties encountered when the angles between resultant tangential forces and slip motion are infinitely close, 2) provides accurate solutions for two-dimensional systems under fierce planar motions, and 3) calculates the responses of the mass within a reasonable period. We compare the computation accuracy, efficiency, and robustness of the proposed frictional algorithm and the previous frictional algorithm [1] through several representative scenarios. We reveal that the proposed algorithm has superior computation accuracy, efficiency, and robustness for two-dimensional frictional problems involving slip/stick transitions and sharp bending.

Effect of specific functional groups on oil adhesion from mica substrate: Implications for low salinity effect

Jiazhong Wu,Fanghui Liu,Hui Yang,Shijing Xu,Quan Xie,Minghui Zhang,TING CHEN,Guangxin Hu,Jinben Wang 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.56 No.-

Low salinity effect has been in the center of attention as a cost-effective and environmentally friendlytechnique. Wettability alteration of the oil/brine/mica system appears to be the identified mechanism(s)to trigger the low salinity effect. While the effect of water chemistry and minerology on the wettability ofthe system has been extensively investigated, few studies have investigated the effect of specific functiongroups from crude oil on the system wettability, limiting the understanding of how specific functionalgroup contributes to the wettability. We thus experimentally measured the adhesion forces betweenmica surfaces and functional groups (e.g., C6H5–, CH3–, COOH–, and NH2–) in the presence of differentaqueous ionic solutions using chemical force microscopy (CFM). Moreover, to understand thecontribution of the structural force, the traditional Derjaguin–Landau–Verwey–Overbeek (DLVO) theorywas extended (denoted as EDLVO) tofit the force profiles using a Gauss model. Our results showed thatthe adhesion force between mica and functional groups in a decreasing order was –NH2> –COOH> –CH3> –C6H5. We also found that while DLVO forces strongly affected the tip-surface contact due to theinteractions among oil/brine/mica interfaces, the structural forces also played an important role in adistance of 1–20 nm due to the presence of H-bonds between COOH-terminated or NH2-terminated tipand mica surface. We therefore conclude that the structural force largely contributes to the adhesionforce due to the hydrophilicity or polarity of functional groups, and nucleophilic property (such as phenylgroup). Our results suggest that the polarity of the crude oil needs to be considered to screen a candidatereservoir for low salinity waterflooding projects.