Wood flour (WF) filled polymer composites are widely used in our daily life. Unfortunately, a wick effect of WF during burning seriously deteriorates the flame retardancy of wood-plastic composites. ...Traditional flame retardants cannot efficiently restrict the wick effect of WF due to their random distribution. In this work, amino glycerin decorated ammonium polyphosphate (APD-APP) was well designed and prepared through an ion exchange reaction to tailor the dispersion of flame retardant in WF-filled polymer composites. When the APD-APP was incorporated into the WF/polypropylene composite (WPC), it showed significantly different distribution compared to that of APP and mainly accumulated at the surface of WF, and then resulted in the formation of core-shell WF@APD-APP. More importantly, the flame retardancy of WPC/APD-APP is remarkably superior to that of WPC/APP. In vertical burning test, 25.0 wt% of APD-APP upgraded the UL-94 rating and limiting oxygen index (LOI) of WPC from no rating and 19.0% to the corresponding V-0 rating and 29.0%. Moreover, the melt dripping of WPC was completely eliminated by APD-APP. In the combustion test, the peak of heat release rate and total smoke production for WPC were respectively decreased by 70.0% and 76.6% in the presence of 30.0 wt% of APD-APP. In addition, mechanical properties of WPC/APD-APP are also superior to that of WPC/APP. The mechanism for the excellent flame retardancy of WPC/APD-APP revealed that the formed core-shell WF@APD-APP affected a residual network through the intergrowth charring of APD-APP and WF during thermally decomposing, and then the wick effect of WF was significantly weakened. Finally, the flame retardancy of WPC/APD-APP was enhanced through typical intumescent flame-retarding action via simultaneous interfacial and bulk charring.
Purpose
Social shopping website (SSW) introduce the social side into the shopping process, thus making “window” shopping or browsing more interesting for customers. The purpose of this paper is to ...investigate customer online browsing experience and its antecedents (i.e. information quality and social interaction) and consequences (i.e. urge to buy impulsively and continuous browsing intention) in the context of SSW.
Design/methodology/approach
A survey questionnaire was distributed to visitors of online SSW to collect data, and partial least squares technology was used to test the research model.
Findings
The results of this study reveal that three types of web browsing, namely, utilitarian browsing, hedonic browsing and social browsing, take place in a SSW. The unique factors of SSW, namely, the quality of user generated contents and social interaction are critical for facilitating customers’ browsing experiences. Furthermore, the findings reveal that hedonic browsing experience is found to be the most salient factor influencing customers’ urge to buy impulsively and continuance intention.
Practical implications
The findings suggest that practitioners, such as designers and managers of SSW should give special attention to the benefits of browsing activity to convert web browsers into impulse purchasers and increase customers’ loyalty. Moreover, they should focus on improving the quality of user generated content and pay more attention to support and encourage social interaction to enhance browsing experiences on a SSW.
Originality/value
Existing studies about browsing behavior mostly focus on traditional online e-commerce website. This study represents the first step toward understanding browsing activity on SSW. Moreover, prior studies mainly focused on utilitarian and hedonic browsing experience; however, there is a lack of research on social browsing experience. The current study attempts to fill this research gap.
Engineering design optimization in real life is a challenging global optimization problem, and many meta-heuristic algorithms have been proposed to obtain the global best solutions. An excellent ...meta-heuristic algorithm has two symmetric search capabilities: local search and global search. In this paper, an improved Butterfly Optimization Algorithm (BOA) is developed by embedding the cross-entropy (CE) method into the original BOA. Based on a co-evolution technique, this new method achieves a proper balance between exploration and exploitation to enhance its global search capability, and effectively avoid it falling into a local optimum. The performance of the proposed approach was evaluated on 19 well-known benchmark test functions and three classical engineering design problems. The results of the test functions show that the proposed algorithm can provide very competitive results in terms of improved exploration, local optima avoidance, exploitation, and convergence rate. The results of the engineering problems prove that the new approach is applicable to challenging problems with constrained and unknown search spaces.
•A novel isobaric A-CAES system based on volatile fluid has been proposed.•Waste heat has employed to make IA-CAES more efficient and stable.•Proposed IA-CAES is more efficient and capacity than ...A-CAES.•CO2 is selected as volatile fluid for its environmentally properties and high saturation pressure.•Mixtures contain CO2 are investigated to enhance the working temperature range of IA-CAES.
Adiabatic compressed air energy storage (A-CAES) is regarded as a promising and emerging storage technology with excellent power and storage capacity. Currently, efficiencies are approximately 70%, in part due to the issue of exergy losses during the throttling of compressed air. To increase the performance of the system, a novel isobaric adiabatic compressed air energy storage (IA-CAES) is proposed on the base of volatile fluid. The air storage vessel is divided into two parts by a piston, one part for air storage and the other has introduced into suitable volatile fluid. The waste heat is utilized to keep the volatile in a desirable pressure in discharging process, which impairs the effect of ambient temperature on pressure of volatile and makes the IA-CAES system stable. CO2 is selected as the pure volatile fluid own to its environmentally properties and high saturation pressure, while the IA-CAES system based on the CO2 can work in the mid and high latitudes only, due to its low critical temperature (304.13 K). 3 binary mixtures namely CO2/HC-600, CO2/HFC-32 and CO2/HFO-1234ze(E) are investigated to improve the critical temperature of CO2, trends to adapt to a wide range of ambient temperatures for IA-CAES system. The thermodynamic analysis including energy analysis, exergy analysis and the parametric analysis are evaluated by using steady-state mathematical model and thermodynamic laws. The calculations show, when CO2 is selected as the pure volatile fluid and the ambient temperature is higher than 288.15 K (15 °C), the average of total exergy efficiency (TEE) of IA-CAES improves more than 4% compared with that of A-CAES. When the waste heat is considered as free, the round trip efficiency (RTE) improved more than 6% and power capacity increased by more than 49% compared to the conventional A-CAES system. The CO2/HC-600 mixture with the compositions 0.85/0.15 has been proposed as the mixture volatile fluid. Compare with the conventional A-CAES system, the RTE and discharge time improved 6.26% and increased by 56.44%, respectively. Meanwhile, a parametric analysis is also carried out to evaluate the effects of several key parameters on the system performance of the IA-CAES systems.
► The new CCHP system combines a Brayton cycle and a transcritical CO2 refrigeration cycle. ► CO2 is used as the working fluid, which is a natural substance and beneficial to environment. ► The ...effects of key thermodynamic parameters on the system performance are examined.
In order to utilize renewable energy to meet diverse energy requirements, a new combined cooling, heating and power (CCHP) system is proposed to produce cooling output, heating output and power output simultaneously. This proposed system combines a Brayton cycle and a transcritical CO2 refrigeration cycle with ejector-expansion device, which uses solar energy as the heat source to reduce fossil fuel consumption and alleviate environmental problems. A mathematical model is developed to simulate the new CCHP system with transcritical CO2 driven by solar energy under steady-state conditions, and the thermal efficiency and exergy efficiency are used to evaluate the system performance. The effects of several key thermodynamic parameters on the system performance are examined. The results indicate that increasing turbine inlet pressure and ejector inlet temperature could lower the efficiency of the system, and increasing turbine back pressure and turbine inlet temperature could elevate the efficiency of system. In addition, as ejector back pressure increases, the thermal efficiency of system decreases, but the exergy efficiency increases.
PurposeThe intense competitive and dynamic environment in mobile social-media market forces service providers to introduce incremental technological changes to achieve sustainable competitive ...advantage. The purpose of this paper is to investigate what and how the user attitude to change influences members' behavioral support for incremental technological change in mobile social media service.Design/methodology/approachUsing the tripartite model of attitude, this study examines the influence of the cognitive aspect (empowerment with change), affective aspect (arousal with change) and behavioral aspect (habit to change) of attitude toward change on members' behavioral support for incremental technological change. Drawing on the commitment to change theory, we assessed the underlying mechanism by which attitudes toward change influences behavioral support for incremental technological change through the two components of commitment to change (i.e. affective and normative commitment to change). We tested the model using structural equation modeling on the data collected from the popular mobile social media services in China.FindingsOur results indicate that the effect of empowerment with change, arousal with change and habit to change varies with different dimensions of commitment to change and significant influence of commitment to change on members' behavioral support for incremental technological change.Practical implicationsThe findings of this study contribute to better insights for services providers for implementing incremental technological change strategies.Originality/valueThis study contributes to the theory of incremental technological changes by empirical examination of the impacts of users' attitudes toward change on members' behavioral support for incremental technological change in mobile social media. The paper extends the commitment to change theory with the discussion of the mediating effect of commitment to change in the continuing members' behavioral support for incremental technological change in mobile social media.
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•Benzaldehyde decorated octadecylamine for tailor-made thermal management.•Self-crosslinking of aromatic Schiff base for molecular firefighting.•Extensively reversible thermal ...transformation in a wide range of 30–100 °C.•Open a window for designing multifunctional phase change materials.
More than 40% of the energy generated globally is consumed by residential and commercial buildings, so energy efficient materials for buildings are urgently needed at present. On-demand thermal energy storage/release using phase change materials (PCMs) can improve thermal energy utilization efficiency, however, they are facing low adaptability to temperature and easy flammability in the case of fulfilling high thermal management capacity. Herein, we report octadecylamine-based PCMs with tailor-made molecular firefighting and thermal energy management capability. These synthesized octadecylamine-based Schiff base-containing PCMs (SB-PCMs) may self-extinguish while encountering short-time fire and possess variable phase transition temperatures of 33, 42, 92, and 101 °C. Meanwhile, these SB-PCMs own high phase transition enthalpies of 161.4–183.4 J g−1 and excellent cyclic stability. When SB-PCMs as thermal energy management materials in wood plastic-based building materials, they show high adaptability to ambient temperature and excellent thermal management capability, achieving temperature regulation of 9.0 °C. Meanwhile, fire safety of the composite wood plastic materials is significantly improved. Detailed analysis confirms that the incorporated benzaldehyde with various positional substituted hydroxyl may induce noncovalent interactions (mainly hydrogen bond and π-π stacking) of SB-PCMs and further control their self-assembling processes, thus achieving multiple thermal responses of SB-PCMs; self-crosslinking charring of benzaldehyde-based Schiff base structure may retard fire spreading, therefore presenting molecular firefighting. Additional multistage thermochromic behaviors of SB-PCMs may extend their application in temperature-sensitive paint, intelligent fabric, etc. This work firstly represents a method for manipulating the multistage thermal and fire responses of PCM in the case of fulfilling high thermal energy management capacity and confirms its molecular-firefighting and energy efficient application in building materials.
Intense competition requires that social media service providers execute two major business strategies: exploiting current functions while simultaneously exploring incremental innovation. Realization ...of these strategies is related to two types of member behavior: reinforced use and varied use. Drawing on identity theories, we examine the common and differential effects of two levels of social self-identity-relational identity and social identity-on reinforced and varied use and the moderating role of inertia on their effects on social media usage. Our results reveal that, although both identities have similar effects on usage behavior, users with higher social identities are more oriented toward variety seeking, while those with stronger relational identities are more oriented toward reinforcement. Inertia negatively moderates the impacts of social identity on social media use, but not the relationships between relational identity and social media use. The current research contributes to theory by decomposing social media usage into reinforced and varied use and reveals the common and differential influences of two levels of social self-identity on user behavior. Social media service providers should focus more on social identity to promote varied use and focus more on relational identity when they want to enhance reinforced use.
Integrating energy storage system into wind system can mitigate the negative effects caused by the intermittent wind. In addition, the spectrum analysis of wind power implies that the hybrid energy ...storage system may have better performance on smoothing out the wind power fluctuations than the independent energy storage system. The main advantage of the hybrid energy storage system is the multi-response speeds. Also, the hybrid energy storage system often operates in the modes switch, partial load and frequent start/stop conditions. Thus, the dynamic behaviors of each devices and the assembly of hybrid energy storage system are important for the system operation and control system design. The design, off-design analysis and parametric analysis of a wind-hybrid energy storage system consisting an A-CAES (adiabatic compressed air energy storage) system and a FESS (flywheel energy storage system) based on spectrum analysis method are carried out in the previous paper (P Zhao et al., 2014). This paper will conduct a preliminary dynamic behaviors analysis of the proposed wind-hybrid energy storage system based on the dynamic models. The simulation results indicate that the total power of wind-hybrid energy storage system can fit the load requirement well, providing an efficient power management for wind power penetration.
•A hybrid energy storage system based on A-CAES and FESS is proposed.•Dynamic model of a wind-hybrid energy storage system is laid out.•Dynamic behaviors of wind-hybrid energy storage system are investigated.•The power output of wind-hybrid energy storage system can fit the load well.
Network security situation awareness enables networks to actively and effectively defend against network attacks, relying on the extraction of network situation elements as an initial and decisive ...step. In existing studies, the stacked sparse autoencoder (SSAE) has been employed to extract features from unlabeled network flows. However, obtaining the optimal hyperparameter combination is challenging due to its numerous hyperparameters. To address this issue, we propose a novel approach named DBO-SSAE that leverages dung beetle optimization (DBO) to select the optimal hyperparameters for SSAE automatically. Applied to the well-known UNSW-NB15 dataset, our model yields an optimal feature subset, which is evaluated across various binary classifiers with different metrics. Experimental results demonstrate that our approach improves accuracy and F 1- measure by 0.2% to 1.5%, while reducing the false negative rate (FNR) and false positive rate (FPR) by 0.06% to 7%, surpassing other feature extraction methods on the same classifier for the UNSW-NB15 dataset. Particularly, in conjunction with a lightweight bidirectional long short-term memory (BiLSTM), our model achieves metrics of 98.84% accuracy , 98.96% F 1- measure , 1.86% FNR , and 0.6% FPR . This study could provide novel insights into the effective representation of network situation elements and lay the groundwork for a high-efficiency intrusion detection system.
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