Analysis on Parameters of Regeneration Subsystem in Liquid Desiccant Dehumidification Systems

Along with the widely use in industries and lives, the dehumidification systems have consumed a large amount of energy. Fortunately, the application of liquid desiccant dehumidification system can greatly reduce the consumption of high-grade energies. To improve the advantages of liquid desiccant system compared with the conventional dehumidification system, one of the key measures is to increase the efficiency of the regeneration sub-system. In this study, models for the regeneration tower and counter-current heat exchanger, which are recognized by previous experiments, are employed and the corresponding VC++ computer program modules are used to describe the heat and mass transfer processes between the liquid desiccant solution and moist air in the regenerator and the heat transfer process in heat exchanger respectively. The orthogonal design is used to arrange the numerical experiment. The results are analyzed by the method of variance analysis to determine the relative significance of operating parameters and the interactions between them. The analysis on the influence factors shows that for the evaporation rate of water vapor in the regenerator, the important parameters are the inlet temperature and concentration of the solution, the mass flow ratio of dry air to dehydrated desiccant, and the NTU of the regenerator. For the regeneration efficiency, the mass flow ratio of dry air to dehydrated desiccant, the NTU of the regenerator and inlet temperature of solution are important parameters. There is no interaction that influences the evaporation rate of water vapor and the regeneration efficiency significantly

Publisher Correction: Copper adparticle enabled selective electrosynthesis of n-propanol.

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Contrasting patterns of community-weighted mean traits and functional diversity in driving grassland productivity changes under N and P addition

Fertilization could influence ecosystem structure and functioning through species turnover (ST) and intraspecific trait variation (ITV), especially in nutrient limited ecosystems. To quantify the relative importance of ITV and ST in driving community functional structure and productivity changes under nitrogen (N) and phosphorous (P) addition in semiarid grasslands. In this regard, we conducted a four-year fertilizer addition experiment in a semiarid grassland on the Loess Plateau, China. We examined how fertilization affects species-level leaf and root trait plasticity to evaluate the ability of plants to manifest different levels of traits in response to different N and P addition. Also, we assessed how ITV or ST dominated community-weighted mean (CWM) traits and functional diversity variations and evaluated their effects on grassland productivity. The results showed that the patterns of plasticity varied greatly among different plant species, and leaf and root traits showed coordinated variations following fertilization. Increasing the level of N and P increased CWM_specific leaf area (CWM_SLA), CWM_leaf N concentration (CWM_LN) and CWM_maximum plant height (CWM_Hmax) and ITV predominate these CWM traits variations. As a results, increased CWM_Hmax, CWM_LN and CWM_SLA positively influenced grassland productivity. In contrast, functional divergence decreased with increasing N and P and showed negative relationships with grassland productivity. Our results emphasized that CWM traits and functional diversity contrastingly drive changes in grassland productivity under N and P addition

Gear faults diagnosis based on wavelet-AR model and PCA

Gear mechanisms are an important element in a variety of industrial applications and about 80% of the breakdowns of the transmission machinery are caused by the gear failure. Efficient incipient faults detection and accurate faults diagnosis are therefore critical to machinery normal operation. The use of mechanical vibration signals for fault diagnosis is significant and effective due to advances in the progress of digital signal processing techniques. Through virtual prototype simulation analysis and experimental study, a novel method for gear multi-faults diagnosis was presented in this paper based on the wavelet-Autoregressive (AR) model and Principal Component Analysis (PCA) method. The virtual prototype simulation and the experimental test were firstly carried out and the comparison results prove that the traditional Fast Fourier Transform Algorithm (FFT) analysis is not appropriate for the gear fault detection and identification. Then the wavelet-AR model was applied to extract the feature sets of the gear fault vibration data. In this procedure, the wavelet transform was used to decompose and de-noise the original signal to obtain fault signals, and the fault type information was extracted by the AR parameters. In order to eliminate the redundant fault features, the PCA was furthermore adopted to fuse the AR parameters into one characteristic to enhance the fault defection and identification. The experimental results indicate that the proposed method based on the wavelet-AR model and PCA is feasible and reliable in the gear multi-faults signal diagnosis, and the isolation of different gear conditions, including normal, single crack, single wear, compound fault of wear and spalling etc., has been effectively accomplished

Optimization Method of Fog Computing High Offloading Service Based on Frame of Reference

The cost of offloading tasks is a crucial parameter that influences the task selection of fog nodes. Low-cost tasks can be completed quickly, while high-cost tasks are rarely chosen. Therefore, it is essential to design an effective incentive mechanism to encourage fog nodes to actively participate in high-cost offloading tasks. Current incentive mechanisms generally increase remuneration to enhance the probability of participants selecting high-cost tasks, which inevitably leads to increased platform costs. To improve the likelihood of choosing high-cost tasks, we introduce a frame of reference into fog computing offloading and design a Reference Incentive Mechanism (RIM) by incorporating reference objects. Leveraging the characteristics of the frame of reference, we set an appropriate reference task as the reference point that influences the attraction of offloading tasks to fog nodes and motivates them towards choosing high-cost tasks. Finally, simulation results demonstrate that our proposed mechanism outperforms existing algorithms in enhancing the selection probability of high-cost tasks and improving platform utility

HIV/AIDS patients' medical and psychosocial needs in the era of HAART: a cross-sectional study among HIV/AIDS patients receiving HAART in Yunnan, China.

Since the launch of China's Free Antiretroviral Therapy (ART) Program in 2002, more than 100,000 HIV/AIDS patients have been treated with highly actively antiretroviral therapy (HAART). However, the current evaluation system for this program mainly focused on its medical outcomes. This study aims to evaluate the medical and psychosocial needs of HIV/AIDS patients after initiating HAART. A cross-sectional study was conducted among 499 HIV/AIDS patients who were currently being treated with HAART in three designated hospitals in Luxi City, Yunnan Province. A questionnaire was used to collect information about participants' demographic characteristics, perceived HIV-related stigma, physician-patient relationship, quality of life, family functioning, etc. Patients' medical records in the National HIV Information System were linked with their questionnaire by their ART identification number. Patients on HAART who were infected with HIV through injection drug use and were current smokers typically had poorer physical health than other participants on HAART. Better financial status and better physician-patient relationship were associated with both physical and psychological well-being. Family awareness of the patient's HIV status was negatively associated with the patient's psychological well-being. Higher levels of perceived HIV-related stigma were associated with poorer psychological health and poorer family functioning. This study emphasizes the importance of assuring a caring environment in China's AIDS treatment program and re-enforces the need to combat the stigma encountered with health providers and the public

Effect of Nano-Clay Dispersion on Pore Structure and Distribution of Hardened Cement Paste

Nano-clay has the potential to improve the properties of cement-based materials. However, the effectiveness of this improvement is influenced by the dispersion of the nano-clay. The effects of different nano-clay dispersion techniques on cement-based material properties and pore structure complexity were studied. The samples were prepared using manual and mechanical dispersion methods. The mechanical properties of the specimens were evaluated, and the pore characteristics of the cement-based materials were analysed using mercury intrusion porosimetry. The study investigated the effect of the dispersion method on the nano-clay dispersion. The complexity of the pore structure was evaluated using a fractal model, and the relationship between the fractal dimension, mechanical properties, and pore structure was analysed. The findings indicate that mechanical dispersion results in better dispersion than manual dispersion, and the mechanical properties of mechanical dispersion are superior to those of manual dispersion. Nano-clay particles can improve the internal pore structure of cement materials. Through mathematical calculation, the surface fractal dimension is between 2.90 and 2.95, with good fractal characteristics. There is a good correlation between the surface fractal dimension and the mechanical properties. The addition of nano-clay can reduce the complexity of the pore structure, and the fractal dimension has an excellent linear relationship with the pore structure