Pretreatment is widely used before drying of agro-products to inactivate enzymes, enhance drying process and improve quality of dried products. In current work, the influence of various pretreatments ...on drying characteristics and quality attributes of fruits and vegetables is summarized. They include chemical solution (hyperosmotic, alkali, sulfite and acid, etc.) and gas (sulfur dioxide, carbon dioxide and ozone) treatments, thermal blanching (hot water, steam, super heated steam impingement, ohmic and microwave heating, etc), and non-thermal process (ultrasound, freezing, pulsed electric field, and high hydrostatic pressure, etc). Chemical pretreatments effectively enhance drying kinetics, meanwhile, it causes soluble nutrients losing, trigger food safety issues by chemical residual. Conventional hot water blanching has significant effect on inactivating various undesirable enzymatic reactions, destroying microorganisms, and softening the texture, as well as facilitating drying rate. However, it induces undesirable quality of products, e.g., loss of texture, soluble nutrients, pigment and aroma. Novel blanching treatments, such as high-humidity hot air impingement blanching, microwave and ohmic heat blanching can reduce the nutrition loss and are more efficient. Non-thermal technologies can be a better alternative to thermal blanching to overcome these drawbacks, and more fundamental researches are needed for better design and scale up.
Short single‐wall carbon nanotubes (SWCNTs)/epoxy composites were fabricated by a procedure of cutting and functionalizing SWCNTs, dispersion and curing, with a very low weight ratio of SWCNTs from ...0.03% to 0.5%. It was found that the tensile fracture strength of composites increases with increasing SWCNT content initially, then reaches a maximum at 0.05 wt% and finally decreases with further increasing the SWCNT content. The fracture strength of the composite with 0.05 wt% SWCNTs (78.46 MPa) is ~160% of that of pure epoxy sample (48.64 MPa). A model analysis based on the competition of local matrix fracture and the debonding of short SWCNT was proposed. It revealed that there is a transition from local matrix fracture to the debonding of SWCNT when the SWCNT content increases, this transition leads to the decrease in the tensile strength. Further analyses indicated that the content of carbon nanotubes (CNTs) at the transition depends on their radius and length. Considering the effect of surface cracks on the fracture strength of pure epoxy sample, the theoretical analyses are qualitatively in agreement with the experimental results. The present study partly explains why the fracture strength of CNT reinforced composites has various results for a similar CNT loading in previous works.
A schematic representation of the model cell of single‐wall carbon nanotubes (SWCNT) reinforced epoxy composites (A) and the forces suffered by SWCNT and matrix (B). A prediction dependence of fracture stress on the SWCNT content in the composites is given in (C).
With a growing demand for safe, nutritious, and fresh-like produce, a number of disinfection technologies have been developed. This review comprehensively examines the working principles and ...applications of several emerging disinfection technologies. The chemical treatments, including chlorine dioxide, ozone, electrolyzed water, essential oils, high-pressure carbon dioxide, and organic acids, have been improved as alternatives to traditional disinfection methods to meet current safety standards. Non-thermal physical treatments, such as UV-light, pulsed light, ionizing radiation, high hydrostatic pressure, cold plasma, and high-intensity ultrasound, have shown significant advantages in improving microbial safety and maintaining the desirable quality of produce. However, using these disinfection technologies alone may not meet the requirement of food safety and high product quality. Several hurdle technologies have been developed, which achieved synergistic effects to maximize lethality against microorganisms and minimize deterioration of produce quality. The review also identifies further research opportunities for the cost-effective commercialization of these technologies.
•Hybrid Bi-LSTM model to forecast of short-term daily ET0 under limited meteorological variables.•Three meteorological inputs (Tmax, Tmin and H) provides the best results.•Hybrid Bi-LSTM model, ...adjusted HS method, and the general Bi-LSTM model were used.•Sunshine duration as one of important meteorological variables to forecast ET0 in semi-arid region.
As the standard method to compute reference evapotranspiration (ET0), Penman-Monteith (PM) method requires eight meteorological input variables, which makes it difficult to apply in data scarce regions. To overcome this problem, a hybrid bi-directional long short-term memory (Bi-LSTM) model was developed to forecast short-term (1–7-day lead time) daily ET0. The model was trained, validated and tested using three meteorological variables for the period of 2006–2018 at selected three meteorological stations located in the semi-arid region of central Ningxia, China. The performance of the hybrid Bi-LSTM model to forecast short-term daily ET0 was evaluated against daily ET0 calculated by the Penman-Monteith method using the statistical metrics namely, mean absolute error (MAE), root mean square error (RMSE), Pearson's correlation coefficient (R) and Nash-Sutcliffe efficiency (NSE). The results showed that the hybrid Bi-LSTM model with a combination of three meteorological inputs (maximum temperature, minimum temperature and sunshine duration) provides the best forecast performance for short-term daily ET0 at the selected meteorological stations. When averaged across stations, the statistical performance at different forecast lead time were as follows; 1-day lead time: RMSE = 0.159 mm day−1, MAE = 0.039 mm day−1, R = 0.992, NSE = 0.988; 4-day lead time: RMSE = 0.247 mm day−1, MAE = 0.075 mm day−1, R = 0.972, NSE = 0.985 and 7-day lead time: RMSE = 0.323 mm day−1, MAE = 0.089 mm day−1, R = 0.943, NSE = 0.982. Moreover, the hybrid Bi-LSTM model consistently improved the forecast performance of short-term daily ET0 compared to the adjusted Hargreaves-Samani (HS) method and the general Bi-LSTM model. The hybrid Bi-LSTM model developed in this study is currently integrated into the modern intelligent irrigation system of 30 ha of Lycium barbarum plantation in central Ningxia in China, a region with limited meteorological data. It is recommended however that the hybrid Bi-LSTM should be evaluated across a wide range of climatic conditions in different regions of the world.
Grasping force control is important for multi-fingered robotic hands to stabilize the grasped object. Humans are able to adjust their grasping force and react quickly to instabilities through tactile ...sensing. However, grasping force control through tactile sensing with robotic hands is still relatively unexplored. In this paper, we make use of tactile sensing for multi-fingered robot hands to adjust the grasping force to stabilize unknown objects without prior knowledge of their shape or physical properties. In particular, an online detection module based on Deep Neural Network (DNN) is designed to detect contact events and object material simultaneously from tactile data. In addition, a force estimation method based on Gaussian Mixture Model (GMM) is proposed to compute the contact information (i.e., contact force and contact location) from tactile data. According to the results of tactile sensing, an object stabilization controller is then employed for a robotic hand to adjust the contact configuration for object stabilization. The spatio-temporal property of tactile data is exploited during tactile sensing. Finally, the effectiveness of the proposed framework is evaluated in a real-world experiment with a five-fingered Shadow Dexterous Hand equipped with BioTac sensors.
Semiconducting metal oxide-based nanowires (SMO-NWs) for gas sensors have been extensively studied for their extraordinary surface-to-volume ratio, high chemical and thermal stabilities, high ...sensitivity, and unique electronic, photonic and mechanical properties. In addition to improving the sensor response, vast developments have recently focused on the fundamental sensing mechanism, low power consumption, as well as novel applications. Herein, this review provides a state-of-art overview of electrically transduced gas sensors based on SMO-NWs. We first discuss the advanced synthesis and assembly techniques for high-quality SMO-NWs, the detailed sensor architectures, as well as the important gas-sensing performance. Relationships between the NWs structure and gas sensing performance are established by understanding general sensitization models related to size and shape, crystal defect, doped and loaded additive, and contact parameters. Moreover, major strategies for low-power gas sensors are proposed, including integrating NWs into microhotplates, self-heating operation, and designing room-temperature gas sensors. Emerging application areas of SMO-NWs-based gas sensors in disease diagnosis, environmental engineering, safety and security, flexible and wearable technology have also been studied. In the end, some insights into new challenges and future prospects for commercialization are highlighted.
Although cilia loss and cell transformation are frequently observed in the early stage of tumorigenesis, the roles of cilia in cell transformation are unknown. In this study, disrupted ciliogenesis ...was observed in cancer cells and pancreatic cancer tissues, which facilitated oncogene-induced transformation of normal pancreatic cells (HPDE6C7) and NIH3T3 cells through activating the mevalonate (MVA) pathway. Disruption of ciliogenesis up-regulated MVA enzymes through β catenin-T cell factor (TCF) signaling, which synchronized with sterol regulatory element binding transcription factor 2 (SREBP2), and the regulation of MVA by β-catenin-TCF signaling was recapitulated in a mouse model of pancreatic ductal adenocarcinoma (PDAC) and human PDAC samples. Moreover, disruption of ciliogenesis by depleting
dramatically promoted tumorigenesis in the PDAC mouse model, driven by
, which was inhibited by statin, an inhibitor of the MVA pathway. Collectively, this study emphasizes the crucial roles of cilia in governing the early steps of the transformation by activating the MVA pathway, suggesting that statin has therapeutic potential for pancreatic cancer treatment.
•Examined the purposes of thermal blanching.•Summarized the indicators for assessment of blanching process.•Outlined the principles, applications and limitations of thermal blanching ...technologies.•Identified and discussed the future trends of thermal blanching.
Thermal blanching is an essential operation for many fruits and vegetables processing. It not only contributes to the inactivation of polyphenol oxidase (PPO), peroxidase (POD), but also affects other quality attributes of products. Herein we review the current status of thermal blanching. Firstly, the purposes of blanching, which include inactivating enzymes, enhancing drying rate and product quality, removing pesticide residues and toxic constituents, expelling air in plant tissues, decreasing microbial load, are examined. Then, the reason to why indicators such as POD and PPO, ascorbic acid, color, and texture are frequently used to evaluate blanching process is summarized. After that, the principles, applications and limitations of current thermal blanching methods, which include conventional hot water blanching, steam blanching, microwave blanching, ohmic blanching, and infrared blanching are outlined. Finally, future trends are identified and discussed.
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