•Composite of chitosan and κ-carrageenan was firstly reported in horticultural crops.•Chitosan-and κ-carrageenan-based composite coating reduced weight loss of dragon fruit.•The composite coating ...maintained bract colour and chlorophyll content.•A higher chlorophyll content in the bract was obtained by GA3 or MeJA pretreatment.•The composite coting was a crucial step of postharvest handling of dragon fruit.
Dragon fruit undergoes rapid senescence resulting in yellowing and wilting of bracts during storage. This study identified the synergistic effect of gibberellic acid (GA3) or methyl jasmonate (MeJA) dipping combined with chitosan- and κ-carrageenan-based composite coating on the postharvest quality of dragon fruit during storage at 10 °C, 90–95 % RH. Coating with 1.0 % chitosan and 0.2 % κ-carrageenan- based composite decreased the fruit weight loss to lower than 5 % after 30 days of storage and had a positive effect on reducing disease infection. Fruit dipped in 50 mg L−1 GA3 or 0.1 mM MeJA for 5 min was maintained a better bract quality compared to the control. The treatment of 1.0 % chitosan and 0.2 % κ-carrageenan- based composite combined with 50 mg L−1 GA3 or 0.1 mM MeJA pretreatment retained a higher chlorophyll content in bracts (47.98 and 48.43 mg 100 g−1 DW, respectively) compared to the coating alone with 1.0 % chitosan and 0.2 % κ-carrageenan- based composite (45.46 mg 100 g−1 DW) via inhibiting the activities of chlorophyll-degrading enzymes. However, bract colour was maintained in all coating treatments compared to the control. The composite coating alone or pretreatment with MeJA significantly maintained titratable acidity, while the combination of GA3 or MeJA pretreatment and coating retained total soluble solids and increased vitamin C content. No treatment was found to have a significant effect on fruit firmness, ethanol and acetaldehyde, total phenolic content, antioxidant activity, and disease symptoms. We concluded that the chitosan- and κ-carrageenan-based composite coating was crucial for maintaining the freshness and bract colour, and in combination with GA3 or MeJA pretreatment was better in retaining chlorophyll content and dragon fruit eating quality.
Large software projects follow a continuous development process with regular releases during which bugs are handled. In recent years, many software projects shifted to rapid releases that reduce ...time-to-market and claim a faster delivery of fixed issues, but also have a shorter period to address bugs. To better understand the impact of rapid releases on bug handling activity, we empirically analyze successive releases of the Eclipse Core projects, focusing on the bug handling rates and durations as well as the feature freeze period. We study the impact of Eclipse’s transition from a yearly to quarterly release cycle. We confirm our findings through feedback received from five Eclipse Core maintainers. Among others, our results reveal that Eclipse’s bug handling process is becoming more stable over time, with a decreasing number of reported bugs before releases, an increasing bug fixing rate and an increasingly balanced bug handling workload before and after releases. The transition to a quarterly release cycle continued to improve bug handling. In addition, more effort is spent on bug fixing during the feature freeze period, while the bug handling rates do not differ between both periods.
•Rapid releases have allowed Eclipse to have a more stable bug handling process.•No observable negative effect of the switch to quarterly releases.•Adopting rapid releases requires careful planning and tracking of the adoption.•Adopters of rapid releases should test and fix bugs as soon as possible.•More intense bug handling activity is observed during the feature freeze periods.
To reduce the energy consumption of the heating, ventilation and air conditioning system, a novel dual heat source warm-air heating system (DWAHS) was developed in this study. A dual heat source air ...source heat pump was applied to satisfy the warm air segmented handling process first time. The theoretical model of the system was established, and ecofriendly refrigerants, such as R290, R600, R134a, R600a and R1234yf were adopted as the working fluids. The system performance indicators, including the energy efficiency ratio (EER), heat volumetric heating capacities (qv), and exergy loss (Exd), were investigated and compared with those of a conventional single heat source warm-air heating system (SWAHS). The results showed that the DWAHS significantly reduces Exd by handling the supply air segmented using 35 and 60 °C hot water, which were simultaneously supplied by a dual heat source air source heat pump. Among the refrigerants, eco-friendly refrigerants R290 and R600 exhibited the best performance under low and high air-temperature conditions, respectively. Moreover, the DWAHS achieved an increase of 13.3%–64.3% in EER and qv when compared with the SWAHS under different operational temperatures. In addition, the DWAHS reduced the Exd by 13.8%–42.7% compared with the SWAHS. Finally, the Exd of the heat pump consumed a significant part of the warm-air heating system Exd at low environmental temperatures. However, the percentage of the Exd of the air-handling process significantly increased with the temperature of the environment.
•A novel dual heat source warm air heating system is proposed.•The system energy and exergy performance are investigated.•The system using different ecofriendly refrigerants are compared.•The novel system outperforms the conventional system significantly.
The stand-alone energy production for power generation, heating or cooling is an usual method for low-medium grade energy utilization. To enhance the energy utilization efficiency, a combined ...cooling, heating, and power (CCHP) system, which is based on two-stage vapor compression cycle (TSVCC) and organic Rankine cycle (ORC), is proposed with temperature and humidity independent control (THIC). The essential parameters are changed to enhance the CCHP performances based on the thermodynamic model constructed. Moreover, the cooling performance are evaluated under different energy-supply scenarios, and the coupling effects of the CCHP are demonstrated through the THIC strategies. The results display that when the return air and fresh air are treated with energy of corresponding grade respectively, the higher outdoor relative humidity and the lower fresh air ratios are beneficial for enhancing refrigeration performance. The adverse effects of condensation temperature on both the economic and environmental performance far surpasses that of sub-cooling degree. With a rise of 10 °C in condensation temperature and sub-cooling degree, the economic performance decreases by 27.89% and 3.7% respectively, while the environmental performance decreases by 24.33% and 0.35% respectively. Furthermore, the proposed system can be switched to variant models according to different strategies in seasons to improve efficiency of energy utilization, which could be used in engineering applications.
Purpose : In the aviation industry, we will investigate the impact of users’ acceptance of technology on their usage behavior and find out the factors that affect their acceptance of technology. We ...will expand the prior study to find out the impact of the self-service technology of Incheon Airport. Research design, data and methodology : Within the last six months, the survey was conducted on people using self-service technology at Incheon International Airport from July to August 2019. Part 307 of the valid questionnaires were used for this final analysis. The collected data were used to perform frequency, factor, reliability, and multiple regression analyses using the SPSS statistical package. Results : Individual aspects of external variables, service aspects and system aspects have been shown to affect usefulness and perceived ease of use. Also, perceived ease-of-use and usefulness have effects on users' intention to accept technology. Conclusions : The perceived easement and perceived usefulness of Incheon International Airport has been shown to affect self-service users. Increasing the user's self-efficiency and increasing the user's expectations for benefits, convenience, rapid processing, and minimal effort will have a positive meaningful effect on the intention of accepting the technology.. KCI Citation Count: 3
Electrostatic charging of powders becomes important, when particles become smaller, especially for fine powders at micron or sub-micron size. Charging of powders causes strong particle adhesion and ...consequently difficulties in processes such as blending or mixing, and sieving, etc. Not only does the charge of powders influence the process and the quality of the products, but also the discharge creates risks of dust explosion. Assessing powder charge and the hazards in manufacturing can be difficult. One of the major challenges is to evaluate the charge levels and polarity in the powders but this requires a significant number of tests to detect charge tendency and distributions in bulk materials, which is time-consuming. In this paper, electrostatic charging of powders in material handling processes and the associated hazards are briefly reviewed. For an assessment, the challenges for sensing electrostatic charges of particulate solids, particularly for fine powders, are discussed. It was revealed that sensing the charge polarity for representative samples of powders can be the main challenge because of the difficulty in separation of the charged particles. The inductive charge sensor showed great potential to measure charge levels and polarity distributions in powders. Experimental trials for several fine powders showed that the inductive charge sensor can be used for rapidly assessing chargeability and charge polarity distribution of powders.
•Investigating air handling process using exergy and entransy analyses.•Reasons leading to exergy destruction and entransy dissipation are clarified.•Uniformity of driving force is depicted by ...unmatched coefficient ξ.•Approaches to improve the humid air handling process are proposed.•Case studies are carried out with focus on reducing unmatched exergy destruction.
Humid air handling process is an important component of the air-conditioning system. In the present study, air handling process between air and water or liquid desiccant are investigated from the perspectives of exergy and entransy analyses. Choosing typical inlet air states as examples, exergy destructions ΔEx,des and entransy dissipations ΔEn,dis are represented in the (1-T0/T)-Q diagram and the T-Q diagram respectively. Unmatched coefficient ξ is defined as the index to depict the uniformity of driving force (ΔT or Δω), which is always higher than or equal to 1. Reasons leading to ΔEx,des and ΔEn,dis are then clarified with the help of ξ. It’s indicated that dissipations or destruction occurred during the heat and mass transfer processes are mainly due to the limited transfer capability and the unmatched properties. The heat and mass transfer process approaching to the saturation line is recommended between air and water, with an unmatched coefficient approaching to 1 and a least destruction or dissipation resulted from ξ. Case studies are carried out with emphasis on reducing the unmatched exergy destruction. The water is recommended to be heated for humidification rather than the air in the humidifier and similarly the solution should be heated for regeneration, lowering the unmatched exergy destruction. The present research is beneficial for performance optimization of the humid air handling process in the air-conditioning system.
The ever-increasing high density of flights arouses an urgent requirement to improve the effectiveness and performance of ground handling in airport operation. The implementation of coordinated ...airport decision-making quantifies the ground handling process into a series of key milestone nodes, which is more conducive for operators to reduce resource consumption and flight delays. An innovative performance evaluation method for the multiflight ground handling process is proposed based on shared information of milestone nodes in the ground handling. A dynamic performance evaluation model is established, which should superimpose the performance evaluation results of the single-flight ground handling process. Meanwhile, the indicators and weights of the single-flight performance evaluation are obtained by combining the ground handling process prediction and expected value. As time evolves, a matrix method for the multiflight ground handling performance evaluation is proposed to combine the logic and evolution of the process. It is shown that the average prediction accuracy of single-flight ground handling process nodes can be increased to 87.63%. The experimental analysis demonstrates that the objectivity, effectiveness and dynamics of the proposed approach can be the basis for short-term tactics in airport.
•Development of a simple and standardized handling process for ITER Port Plugs using passive guiding means.•Pre-selection of materials and low-friction treatment, compatible with ITER in-Vessel ...environment, based on Tribology tests.•Demonstration of ITER Port Plug Handling process mechanical soundness by successful trials on a physical downscaled mock-up.•Optimization of ITER Port Plug gap configuration based on 3D Tolerance analysis (3DCS).
The Port Plug handling system aims to insert and remove the ITER Port Plugs installed at the Equatorial and Upper levels of the ITER Tokamak. As the Port Plugs activation and contamination levels prevent hands-on access, their safe transfer is ensured by the Cask and Plug Remote Handling System (CPRHS) between the buildings.
The basic principle of the CPRHS is to allow the transfer of the Plug in and out the vessel using passive guiding means permanently attached to the Plug and the Vessel.
This handling process has been reproduced on a scaled-down physical mock-up which has partially demonstrated its reliability from a mechanical point of view. In parallel, a campaign of tribology testing has been performed to identify suitable material compatible with the In-Vessel environmental conditions and with which to optimize the coefficient of friction.
This paper describes the technical activities performed during handling process development (integration, tolerances, mechanical and neutronic analyses) and the results of performed tests.
Additive manufacturing is a rapid manufacturing based on discrete accumulation to achieve prototypes or parts of products. Inorganic non-metallic materials, as one of the three major materials, have ...incomparable application prospect in medical, aerospace, automotive, construction, arts and crafts, as well as many other fields. In order to rapidly create devices with arbitrarily complex shapes, additive manufacturing of inorganic non-metallic materials is becoming a hot spot of current research. In view of the technical types, materials and other aspects, this article introduced research status and development of additive manufacturing in inorganic non-metallic materials at home and abroad. Several common inorganic non-metallic materials are compared and analyzed, such as Al2O3, Si3N4 SiO2, ZrO2, etc. The forming characteristics and the problems of several popular ceramic materials and sand–casting materials are illustrated with emphases. The key problems existed in additive manufacturing forming process of inorganic non-metallic material are pointed out and urgent to be solved at present. Furthermore, the impacts of the material handling process, three dimensional printing (3DP), Selective Laser Sintering(SLS), Selective Laser Melting (SLM) three-dimensional forming processes and post treatment process on the quality and performance of the forming parts are analyzed. Finally, the prospects in SLS of the gem material are put forward.
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