摘要：
Anthocyanin extracts from purple tomato (PTA) were incorporated with polyvinyl alcohol (PVA), resulting in a series of colorimetric PVA/PTA films with PTA concentrations of 0%, 1%, 3%, and 5% (based on PVA). The role of anthocyanin on color response, Fourier-transform infrared (FTIR), thickness, water content, mechanical properties, antioxidant activity, and water vapor permeability (WVP) through the films was examined. In addition, its application in smart packaging to assess the freshness of shrimp was studied. It was found that the tensile strength, contact angle and WVP of PVA/PTA films increases with the addition of more PTA, while the elongation at break and water content decreased. FTIR analysis showed that there are interactions between PTA and the PVA matrix. The addition of anthocyanins caused significant improvement in the antioxidant properties of PVA films. Furthermore, the total volatile alkaline nitrogen (TVB-N), total plate count (TPC), and pH value of shrimp were monitored after 4 days of refrigeration, and the color change of the indexes was recorded. The PVA/PTA films changed color from purple to yellow-green during the storage time of 0-4 days for shrimp. This suggests that the film could be used in smart packaging as a real-time freshness indicator for shrimp.
摘要：
adipate terephthalate (PBAT) as matrix and zinc oxide nanoparticles (ZnONPs) and silver nanoparticles (AgNPs) as antibacterial agents, a series of antibacterial PLA/PBAT films were prepared by melt blending. The weight ratio of PLA, PBAT and nanoparticles in composite films was 70:900:10 (lower loading) or 70:900:20 (higher loading). The results showed that comparing with the PLA/PBAT films, the hydrophilicity, oxygen barrier properties, mechanical performance and antibacterial activities of PLA/PBAT/nanoparticles films were significantly improved (P < 0.05), and influenced by the content and type of nanoparticles. After the addition of nanoparticles, the maximum change of films performance was from 71.3 degrees to 35.8 degrees for water contact angle, from 7.4 x 10(-14) cm(3) cm.cm(-2). s(-1). Pa-1 to 5.5 x 10(-14) cm(3) cm.cm(-2). s(-1). Pa-1 for oxygen transmission permeability, from 26.4 MPa to 31.4 MPa for tensile strength, and from 0% to 57.8% (Escherichia coli) or 58.6% (Staphylococcus aureus) for antibacterial ratio. The films with higher loading content of nanoparticles showed a better antibacterial activity. For the same nanoparticles content, the antibacterial activity of PLA/PBAT/AgNPs was better than PLA/PBAT/ZnONPs. The overall migration in food simulants involving acetic acid (3%) ethanol (10% and 95%) was below 10 mg/dm(2) for most films, however, the overall migration for the films with higher content of AgNPs exceeded the limit value. The fresh noodles packaged by PLA/PBAT/AgNPs films showed the significant lowest total viable count with 4.6 lg (CFU/g) and the best appearance color characterized by L* (lightness), a*(red-green) and b*(yellow-blue) at storage time of 7 d in contrast with PLA/PBAT and PLA/PBAT/ZnONPs films, indicating the potential application of prepared films in active packaging to prolong the shelf life of food.
通讯机构：
[Shen, SN ; Li, H ; Li, H] W;Wuhan Univ, Sch Power & Mech Engn, Wuhan 430072, Peoples R China.;Wuhan Polytech Univ, Sch Mech Engn, Wuhan 430048, Peoples R China.
关键词：
Laser powder bed fusion;Laser ultrasonic detection;Surface roughness;Internal holes;Longitudinal wave
摘要：
In view of the non-destructive and non-contact features, laser ultrasonic (LU) technology has long been the effective method to detect tiny defects for laser powder bed fusion (LPBF) additive manufactured specimens. Of larger concern is the variation and the corresponding mechanism on tested results of LU detection as the property of LPBF additive manufactured specimen is changed. Aiming at the property of surface roughness, this work investigated the propagation characteristics of excited ultrasonic waves in LPBF additive manufactured 316L stainless steel with different surface roughness, as well as the interaction between ultrasonic waves and artificial submillimeter holes. Both numerical simulated and experimental study were conducted. Simulated results revealed that the amplitudes of longitudinal wave (L wave) and its echo wave L1 at the holes exhibited a discernible increase as the surface was coarser. The increase in surface roughness was detrimental to the resolution of defect detection as was expected from the increased amount of noise. LPBF fabrication and the subsequent LU pulse-echo detection were conducted for 316L stainless steel. Both B-scan and C-scan were able to detect the holes with the diameter of 0.6 mm. The speckle phenomenon deriving from the increase in surface roughness emerged, corresponding to the increased ultrasonic signal energy but deteriorated resolution of detected images. It is feasible to optimize LU detected effect by minimize the surface roughness of tested specimens.
作者机构：
[Wang, Ruonan; Cao, Qiang; Wang, Xiaoliang; Li, Fengchang] The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China;[Tian, Xiaoyu] School of Mechanical Engineering, Wuhan Polytechnic University, Wuhan 430048, China
通讯机构：
[Qiang Cao] T;The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
关键词：
Beam shaping;Femtosecond lasers;Lithium niobate;Nonlinear frequency conversion;Nonlinear photonic crystals;Ultrafast lasers
摘要：
We experimentally extend the nonlinear Gaussian to flat-top beam shaping from one to two dimensions through a three-dimensional nonlinear photonic crystal. Employing a near-infrared femtosecond laser, we induce a modification inside lithium niobate to achieve a second-order nonlinear optical coefficient modulation in three dimensions. The flat-topped truncation of wavefront has been adjusted in a mutual perpendicular coordinate separately. Among the generated flat-topped beams, the optimal flatness is 97.1%, and the nonlinear conversion efficiency is 10(-2) at the peak power of 37 kW with the interaction length of 630 µm. By adding an extra dimension, our work simultaneously enables full-wavefront flat-top distribution and nonlinear frequency conversion.
关键词：
Near -Infrared spectroscopy;Rapid non-destructive detection;Grass carp fillets;Total volatile basic nitrogen;Machine learning;Orthogonal signal correction (OSC);Particle swarm optimization algorithm;optimized BP neural network (PSO-BP)
摘要：
This research aims to accurately forecast the freshness indicators (TVB-N) of skinned and skinless grass carp fillets by integrating near-infrared spectroscopy (NIR) with machine learning algorithms. By comparing the predictive accuracy of machine learning models for the two types of grass carp fillets, the most effective modeling method is identified. Methodologically, the study first applies orthogonal signal correction (OSC) and the first derivative among other algorithms for spectral pre-processing. Subsequently, competitive adaptive reweighted sampling (CARS), moving window partial least squares (MWPLS), and random frog (RF) are used for the selection of variables. Lastly, partial least squares regression (PLSR), support vector regression (SVR), backpropagation neural networks (BPNN), and particle swarm optimization-enhanced BP neural networks (PSO-BP) are employed to quantitatively analyze the NIR data. The most relevant results reveal that the (OSC+D1)-CARS-PSO-BP model exhibits superior predictive capabilities. Especially when applied to skin-on fish fillets (R2P =0.988, RMSEP=0.092), this model surpasses that for skinless fish fillet data (R2P =0.987, RMSEP=0.096). Therefore, combining near-infrared with machine learning to predict the freshness (TVB-N) of grass carp fillets based on skin-on samples is a more effective non-destructive testing method.
通讯机构：
[Shen, SN ; Li, H] W;Wuhan Univ, Inst Technol Sci, Wuhan 430072, Peoples R China.
关键词：
Laser powder bed fusion;Laser ultrasonic;Thermo-elastic regime;Internal defect
摘要：
In the development of additive manufacturing (AM) technology, laser powder bed fusion (LPBF) is one of the important processing methods. However, the hole defects in the fabricated samples limit the development. Laser ultrasonic (LU) technology plays a major role in the detection of LPBF parts with tiny defects, which has the advantages of non-contact and non-destructive. In this work, the detection of submillimeter internal defects in four typical LPBF alloys by LU technology is studied numerically and experimentally. A multiphysics simulation model of LU detection is established to investigate the propagation characteristics of excited ultrasonic waves in different LPBF alloys and their interaction with submillimeter artificial defects. Simulation results show that the amplitude of longitudinal (L) wave at the defect is the largest in AlSi10Mg alloy, and the amplitude of L wave in the 316L alloy, Ti6Al4V alloy and In718 alloy are very close, but their phases are slightly different. The amplitude of L wave tends to decrease nearly linearly with the increase in defect diameter. Then, four typical LPBF alloys are fabricated and measured by the LU through-transmission detection. The geometric information of artificial holes with a diameter larger than 0.2 mm are clearly characterized by the LU C-scan results, indicating the prominent applicability and feasibility of LU detection on different materials fabricated by LPBF.
通讯机构：
[Jibing Chen] S;School of Mechanical Engineering, Wuhan Polytechnic University, Wuhan, 420023, China
摘要：
Due to the problems of low welding efficiency, large heat-affected zone, and poor welding quality in the process of welding thin-walled titanium tubes by argon arc welding, there are few studies on the use of high-frequency induction welding (HFIW) of thin-walled titanium alloy tubes. The evolution law of weld microstructure and mechanical properties of the thin-walled titanium tube needs to be further studied because of rapid welding speed and the small heat-affected zone of HFIW. Therefore, a novel manufacturing method via high-frequency induction welding is proposed in this paper to solve the existing problems. With an industrial-grade titanium TA2 tube (wall's thickness is 0.5 mm) as the research object, a comparative study is conducted in this research to examine the morphology, microstructure, microhardness, and tensile characteristics of welded joints at different welding power. The findings demonstrated a significant efficacy of HFIW in resolving these challenges. The mechanical properties and microstructue of heat-affected zone (HAZ) were characterized. The lowest hardness is measured at 202 HV, while the base material was recorded as 184 HV, when the welding speed of HFIW is set at 50 m/min. Meanwhile, the heat-affected zone has the highest hardness at 224 HV, a tensile strength of 446.8 MPa and a post-fracture elongation of 16%. The results showed that HFIW can not only greatly improve the welding efficiency, significantly improve the microstructure of weld joint and HAZ, and improve the mechanical properties of thin-walled titanium pipe, but also provide a highly feasible welding method for welding ultra-thin-walled pipes.
期刊：
Journal of Cleaner Production,2024年440:140972 ISSN：0959-6526
通讯作者：
Wang, JJ
作者机构：
[Cao, Rui; Wang, Jiaojiao] Zhoukou Normal Univ, Coll Mech & Elect Engn, Zhoukou 466001, Peoples R China.;[Wang, Qiaohua] Huazhong Agr Univ, Coll Engn, Wuhan 430070, Peoples R China.;[Ma, Meihu] Huazhong Agr Univ, Natl Res & Dev Ctr Egg Proc, Wuhan 430070, Peoples R China.;[Fu, Dandan] Wuhan Polytech Univ, Coll Mech Engn, Wuhan 430048, Peoples R China.
通讯机构：
[Wang, JJ ] Z;Zhoukou Normal Univ, Coll Mech & Elect Engn, Zhoukou 466001, Peoples R China.
关键词：
Egg;Respiration;Reutilization of unfertilized eggs;Dead embryo;Classification and identification
摘要：
Respiration plays a crucial role in the physiological development of embryos throughout the entire incubation process and serves as a vital indicator for discerning unfertilized eggs and embryos that have stopped development. This article explores the relationship between egg respiration, fertilization status, and chicken embryo viability. First, it studied the changes in respiration of fertilized and unfertilized eggs during the early stages of incubation (Day 1–3) and found that the CO2 production of fertilized eggs gradually increased, while those of unfertilized eggs gradually decreased. Moreover, significant differences in respiration between fertilized and unfertilized eggs were observed on the second day of incubation. Next, we employed Random Forest (RF), Logistic Regression (LR), and Support Vector Machine (SVM) models to differentiate between fertilized and unfertilized eggs. Notably, the SVM algorithm exhibited exceptional performance in discriminating between fertilized and unfertilized eggs, achieving a remarkable test set accuracy of 98.41 %. Finally, a Bayesian algorithm was applied to classify embryos as either dead, weak, or viable in middle and later stages of incubation. Bayesian discriminant analysis yielded compelling results, achieving a 100 % detection rate for deceased embryo eggs. The outcomes of this study provide a robust theoretical foundation and empirical data to advance non-destructive testing methodologies for poultry eggs.
通讯机构：
[Li, B ] W;Wuhan Polytech Univ, Sch Mech Engn, Wuhan 430023, Hubei, Peoples R China.
摘要：
Deep eutectic solvents (DES) were prepared using urea (U) and acrylamide (AM) as hydrogen bond donors (HBD) and choline chloride (ChCl) as hydrogen bond acceptor (HBA), and polyethylene glycol (PEG) was selected as a filler and uniformly dispersed in DES to prepare PEG/P(U-AM-ChCl) composite hydrogels by light polymerization. The composite hydrogels were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The effects of the content of PEG on the swelling properties, mechanical properties and fatigue resistance of the composite hydrogels were investigated. The results showed that the compressive strength and fatigue strength of the composite hydrogels were gradually enhanced with the increase of the PEG content in the composite hydrogels, in which the maximum compressive strength of the hydrogels with 1 wt% PEG added was increased by 1.86 times. The composite hydrogel had excellent swelling properties, and the equilibrium swelling degree of the hydrogel with 1 wt% PEG added reached 10.15. Meanwhile, the PEG/P(U-AM-ChCl) composite hydrogel had excellent self-healing properties, and the self-healing rate of the composite hydrogel with a PFG content of 1 wt% could reach 91.93% after 48 hours of healing. This study provides a convenient and efficient method to prepare composite hydrogels with superior swelling properties and self-healing properties. Deep eutectic solvents (DES) were prepared using urea (U) and acrylamide (AM) as hydrogen bond donors and choline chloride (ChCl) as hydrogen bond acceptor. Polyethylene glycol (PEG) was selected as a filler and uniformly dispersed in DES to prepare PEG/P(U-AM-ChCl) composite hydrogels.
摘要：
Selective laser melting (SLM) additive manufacturing technology with different oxygen contents leads to the appearance of spherical solids of different sizes on the surface of the part, which affects the mechanical properties of the part, surface roughness, etc. In this study, the SLM molding technique was applied using three different 316L metal powders with different oxygen contents. The spheroidization properties and morphology of the samples were observed using a Quanta 200 environmental scanning electron microscope (ESEM), and the samples were observed microscopically and subjected to EDX spectroscopy using metallographic microscopy, and the mechanical properties were investigated. The results of the study showed that when using gas atomized powders, no spheroidization occurred when the oxygen content of the powders was 5.44 +/- 0.01% in all cases, whereas using water atomized powders produced spherical structures with larger dimensions. This observation was closely related to the shape and particle size of the powder. When 316L metal powder with an oxygen content of 4.52 +/- 0.01% was used for molding, small spherical structures appeared on the surface of the samples. When metal powder with an oxygen content of 5.44 +/- 0.01% was used for the molding, larger spherical structures appeared on the surface of the samples. When the powder with an oxygen content of 5.90 +/- 0.01% was used for the molding, more small spherical structures and some large spherical structures appeared on the surface of the samples. This suggests that higher oxygen levels may inhibit the occurrence of spheroidization. EDX spectroscopic analysis revealed that the white matter on the surface of the samples without spheroidization was mainly composed of Fe and Cr, whereas the white matter on the surface of the large-sized spherical structures was mainly composed of Si and Mn, which may be related to the oxygenophilicity of the various substances. Selective laser melting (SLM) additive manufacturing technology with different oxygen contents leads to the appearance of spherical solids of different sizes on the surface of the part, which affects the mechanical properties of the part, surface roughness, etc.
作者机构：
[Chengzhe Yu; Nan Chen; Ruidi Li; Tiechui Yuan] State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083, China;[Shisen Huang] School of Mechanical Engineering, Wuhan Polytechnic University, Wuhan, 430023, China;[Xin Ma; Yi Zhang; Min Huang; Liang Lv; Ruoyu Liu; Yuanyuan Jiang] AECC South Industry Company Limited, Zhuzhou, 412002, China;[Xingyan Liu; Duan Lai] Farsoon Technologies Co., Ltd, Changsha, 410083, China
通讯机构：
[Ruidi Li] S;State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083, China
摘要：
The effect of scanning strategy on the microstructure and properties of GH3536 Ni-based superalloy prepared by Laser Powder Bed Fusion was investigated, for the purpose of building high quality hydrocyclone part. The results show that the strength of Z67° (a zone with 67° hatch angle strategy) specimen is the highest among the four scanning strategies (0°, 67°, 90°and Z67°), with yield strength and tensile strength of 681 MPa and 837 MPa, respectively. Selective orientation of crystals occurs during the forming process because the longitudinal section of the specimen exhibits a high texture strength in (001). As the stretching proceeds, the plastic deformation mechanism of the specimen gradually changes from slip to twin-dominated, a substantial amount of twinning is observed in the region where the deformation of the specimen reaches 80%. The additive manufacturing simulation suite: Ansys Additive is used to simulate the stress and deformation of the part during the process, and the displacement results are consistent with the experimental phenomena. According to the simulation results, the structure design is optimized and the surface quality of the part is improved. The results show that the support of the part is more reasonable when the overhang angle is 45°.
摘要：
This study utilises the transfer matrix method (TMM) to address the acoustic characteristics of multilayered cylindrical shells lined with porous materials. The TMM theoretical model for the sound transmission loss of composite cylindrical shells with internal porous materials is derived by establishing transfer matrices for the air/composite material interface, composite material/foam interface, foam/air interface and boundary interfaces. The accuracy of the TMM model is validated through a comparison and analysis with experimental results. Building upon this, the impact of porous foam material parameters and types on the structural sound transmission loss is discussed. The results indicate that the use of TMM accurately reflects the acoustic performance of composite structures. Additionally, this model allows for the determination of the influence patterns of porous foam material parameters and types on the acoustic performance of composite structures. In the frequency range of 100-10,000 Hz, the sound transmission loss of the melamine foam-lined composite structure increases with the increase in flow resistance and porosity and the decrease of the tortuosity factor. The use of the porous lining material significantly enhances the structural sound insulation performance.
摘要：
This study explores the influence of various ultrasound treatment parameters and microwave drying parameters on the quality and drying characteristics of rice. The rice was treated in an ultrasound water bath (200W) for 30 min, 40 min, and 50 min, followed by microwave drying (210W) for 10 min. The influence of ultrasound treatment time on the moisture content variation of rice was found to be significant through correlation analysis. The time required for the 50 -min ultrasound treatment to reach the safe moisture level (15 %) was approximately 20 % shorter than the time required for the 30 -min ultrasound treatment. Due to the combined ultrasoundmicrowave treatment, changes occur in the constituents of rice (Starch gelatinization, Maillard reaction, etc.), and the variations in rice quality can be reflected by the changes in CIE Lab color parameters. The differences in characteristic peaks of Fourier Transform Infrared Spectroscopy (FTIR) can reflect the variations in flavor and aroma of rice, as well as the significant disruption of the ordered structure of starch molecules. Additionally, response surface experiments based on Box-Behnken design were conducted to obtain the optimal conditions for ultrasound-microwave combined treatment (240W, 46min, 3min). Moreover, ultrasound-microwave combined treatment leads to a significant reduction in rice hardness and an increase in elasticity.
摘要：
As an advanced time-frequency (TF) decomposition (TFD) method, variational nonlinear chirplet mode decomposition (VNCMD) decomposes the original signal into a series of nonlinear chirplet modes (NCMs), such that the inherent characteristic information contained in the signal can be revealed effectively. However, the decomposition ability of VNCMD is largely affected by the prior instantaneous frequency (IF) and the pre-set parameters. In practical engineering applications, the presence of noise and interference components often complicates the accurate determination of prior IFs and appropriate decomposition parameters. Considering the above issues, in order to precisely extract the NCMs and realize the effective analysis of mechanical vibration signals, this paper mainly focuses on the drawbacks of accurate prior IF and the decomposition parameters of VNCMD, and proposed an improved version via local maximum synchrosqueezing transform and a recursive mode extracting scheme. The performance of the proposed method is evaluated through simulation cases, and the results demonstrate its effectiveness. Finally, the proposed method is successfully applied to bearing data analysis and rub-impact fault detection.
摘要：
Polystyrene (PS) is a widely used matrix material in selective laser sintering (SLS). Polystyrene is inexpensive and its powdered form, used as a matrix material in selective laser sintering, enables high accuracy in prototype production, similar to the casting process of wax molds. However, the performance of polystyrene varies significantly due to the differences in its synthetic process and added fillers of different grades available in the market, leading to varying outcomes when used in selective laser sintering technology. Therefore, it is necessary to study the polystyrene materials available in the market to identify the most suitable ones for selective laser sintering technology. In this study, three different grades of polystyrene powder (75-100 mu m) were selected as research objects and treated to sintering experiments using a "selective laser sintering" rapid prototyping machine. The research results indicated that the molecular weight affects the quality of selective laser sintering parts by influencing the melt viscosity of polystyrene, which in turn affects the density and accuracy of the fabricated parts. Guided by these research findings, two 75-100 mu m polystyrene powder materials were selected, and their sintering performance and thermal weight loss characteristics were investigated. Under optimized processing parameters, the test specimens with high accuracy were fabricated by selective laser sintering, and its mechanical property was further reinforced through epoxy resin post-processed, and the microstructure of the tensile fracture surface was examined using electron microscopy. In conclusion, the PS1 type polystyrene material and its process parameters, suitable in selective laser sintering and its post-processing, were determined. The research findings presented in this paper provided a methodology for the selection of selective laser sintering materials.
