Manufacturing and Characterization of Epoxy Based Flexible Thermoelectric Modules

Thermoelectric module can convert waste heat into electricity due to its unique Seebeck effect. Since a great deal of heat produced in households and factories has been wasted. It is significant to collect the waste heat by thermoelectric modules. However, conventional thermoelectric modules mainly possess rigid substrates, which limits their applications in complex situations, such as the industrial pipe and human body. Thermoelectric modules with flexible substrates can overcome this drawback. Flexible thermoelectric module can be bent to adapt to uneven surfaces. Hence, it requires superior mechanical strength in order not to break when bent. The mechanical strength highly relies on the binding material. Binding materials can be classified into solder paste and electrically conductive adhesive. This work presents a new electrically conductive adhesive named 2D-ECA, synthesized by RISE (Research Institutes of Sweden) and Linköping University. Various characterization methods have been applied to study its performance in the device. In this work, we mainly focused on the mechanical strength, electric conductivity and thermoelectric property of 2D-ECA. We found that the mechanical strength of 2D-ECA is as high as superior commercial solder paste and electrically conductive adhesive. What’s more, 2D-ECA will not damage the inherent mechanical strength of the thermoelectric leg as the solder paste. However, the electric resistance of 2D-ECA based samples is considerably higher than solder pastes. As a result, devices fabricated with 2D-ECA showed a relatively lower output power. Hence, further research should focus on improving the electrical conductivity of 2D-ECA. Nevertheless, further study illustrated that 2D-ECA can be used on aluminium substrate, while it is impossible for ordinary solder pastes. It is a significant step towards low-cost devices

Respiratory Rate Estimation from Face Videos

Vital signs, such as heart rate (HR), heart rate variability (HRV), respiratory rate (RR), are important indicators for a person's health. Vital signs are traditionally measured with contact sensors, and may be inconvenient and cause discomfort during continuous monitoring. Commercial cameras are promising contact-free sensors, and remote photoplethysmography (rPPG) have been studied to remotely monitor heart rate from face videos. For remote RR measurement, most prior art was based on small periodical motions of chest regions caused by breathing cycles, which are vulnerable to subjects' voluntary movements. This paper explores remote RR measurement based on rPPG obtained from face videos. The paper employs motion compensation, two-phase temporal filtering, and signal pruning to capture signals with high quality. The experimental results demonstrate that the proposed framework can obtain accurate RR results and can provide HR, HRV and RR measurement synergistically in one framework

Evaluation of acetic acid treatment of fresh–cut water chestnuts using gray–correlation analysis based on the variation–coefficient weight

IntroductionThe demand for fresh–cut water chestnuts, a convenient and nutritive vegetable, is increasing in market. However, the slicing of water chestnuts can cause mechanical damage to tissue, which results in quality deterioration. We aimed to select the optimal treatment through a comprehensive comparison of the preservation effect of acetic acid, which could prolong the shelf life of fresh–cut water chestnuts and improve their storage quality.MethodsA comprehensive evaluation was conducted using the gray–correlation method based on the variation–coefficient weight to observe the treatment of 0, 2 and 5% acetic acid. Their effects on color, weight loss rate, and the content of ascorbic acid, total sugar, reducing sugar, soluble protein, and free amino acid were determined.ResultsThe color, weight loss rate, and nutritional content of fresh–cut chestnuts varied under different processing and storage times. When stored for more than 4 days, the b* value, and the content of total sugar and soluble protein in CK were higher than those in 2% or 5% acetic acid, but the weight loss rate, and the content of ascorbic acid and free amino acid in CK were less than those in acetic acid treatments. Considering various indicators, it was difficult to determine which treatment to choose for fresh–cut water chestnut preservation. The gray–correlation analysis results indicated that when stored for 8, 12, or 16 days, the gray–correlation degree of 5% acetic acid was the highest, while that of the control was the lowest. It could be directly concluded by the gray–correlation degree that when the storage time exceeded 4 days, acetic acid could be used to improve storage quality, and 5% acetic acid had a better preservation effect than 2%. Fresh–cut water chestnuts can be stored for 4 days without the need for acetic acid treatment.ConclusionThese findings could provide information and comprehensive evaluation methods for the preservation of fresh–cut fruits and vegetables. The next step is to evaluate the preservation effect of acetic acid by measuring its effects on other indicators of fresh–cut water chestnuts (e.g., flavonoids, and microorganisms), providing ideas for the research of preservatives

Metagenomic Profiling of the Bacterial Community Changes from Koji to Mash Stage in the Brewing of Soy Sauce

The improvement of soy sauce fermentation is restricted by the insufficient information on bacterial community. In this study, bacterial communities in the koji and mash stage were compared based on next-generation sequencing technology. A total of 29 genera were identi­fied in the koji stage, while 34 in the mash stage. After koji stage, 7 genera disappeared and 12 new genera appeared in the mash stage. The dominant bacteria were Kurthia, Weissella and Staphylococcus in the koji stage and Staphylococcus, Kurthia, Enterococcus and Leuconostoc in the mash stage. The results provided insights into the microbial communities involved in soy sauce fermentation

The Effects of Intelectin-1 on Antioxidant and Angiogenesis in HUVECs Exposed to Oxygen Glucose Deprivation

Objective: Ischemic stroke leads to cellular death and tissue damage by depriving the areas of glucose and oxygen supplies. The effective treatment of stroke remains a challenge for modern medicine. This study used an oxygen-glucose deprivation (OGD) model of human umbilical vein endothelial cells (HUVECs) to mimic ischemic injuries and explored the role and mechanism of intelectin-1.Methods: Intelectin-1 was transduced into the HUVECs using a lentiviral vector. The PI3K/Akt signaling was examined in intelectin-induced eNOS phosphorylation. The PI3K inhibitor LY294002 was dealed in HUVECs.Results: Our results demonstrated an increase in capillary density, decrease in apoptotic cells, and increase in HIF-1α protein expression following intelectin-1 treatment. Real-time PCR and Western blotting revealed the increased intelectin-1 expression alongside eNOS and Akt phosphorylation with enhanced bcl-2 expression under OGD. Capillary density decreased significantly after LY294002 treatment.Conclusion: These results suggest intelectin-1 promotes angiogenesis, inhibits oxidative stress and reduces apoptosis by stimulating the Akt-eNOS signaling pathway in response to ischemia in vitro

Research on Open-circuit Fault Tolerant Control of Six-phase Permanent Magnet Synchronous Machine Based on Fifth Harmonic Current Injection

This paper proposes a novel control approach for fault-tolerant control of dual three-phase permanent magnet synchronous motor (PMSM) under one-phase open-circuit fault. A modified six-phase static coordinate transformation matrix and an extended rotating coordinate transformation matrix are investigated considering the influence of the fifth harmonic space on fault-tolerant control. These mathematical models are further analyzed in the fundamental space and the fifth harmonic space after the fault and to eliminate the coupling between the d-q axis voltage equation in the fundamental wave space and the d-q axis voltage equation in the fifth harmonic space, a secondary rotation coordinate transformation matrix is proposed. To achieve the purpose of reducing torque ripple, the fault-tolerant control method proposed in this paper not only takes the minimum copper loss as the constraint condition, but also injects the fifth harmonic current. The experimental result of current and torque is used to verify the accuracy of fault-tolerant control

Deep Frequency Filtering for Domain Generalization

Improving the generalization capability of Deep Neural Networks (DNNs) is critical for their practical uses, which has been a longstanding challenge. Some theoretical studies have revealed that DNNs have preferences to different frequency components in the learning process and indicated that this may affect the robustness of learned features. In this paper, we propose Deep Frequency Filtering (DFF) for learning domain-generalizable features, which is the first endeavour to explicitly modulate frequency components of different transfer difficulties across domains during training. To achieve this, we perform Fast Fourier Transform (FFT) on feature maps at different layers, then adopt a light-weight module to learn the attention masks from frequency representations after FFT to enhance transferable frequency components while suppressing the components not conductive to generalization. Further, we empirically compare different types of attention for implementing our conceptualized DFF. Extensive experiments demonstrate the effectiveness of the proposed DFF and show that applying DFF on a plain baseline outperforms the state-of-the-art methods on different domain generalization tasks, including close-set classification and open-set retrieval