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Wireless devices consume large amounts of energy during wireless communication. As the energy storage of battery is limited, improving energy efficiency has become an important approach to prolong the lifetime of devices. The IEEE 802.11 protocol supports the power save mode (PSM) in wireless local area networks (WLANs). However, the standard PSM cannot adapt to the changes of traffic load or channel conditions. Therefore, this article proposes an adaptive traffic-aware PSM mechanism (APSM) that improves energy efficiency of wireless devices in a WLAN with an access point (AP). According to the current channel condition and traffic load, the AP adjusts the interval of beacons that give devices different priorities to fetch buffered packets. The devices can adaptively adjust listening intervals according to network traffic, and adopt different congestion backoff timers when channel collisions happen or the network topology changes. The APSM has been implemented and evaluated in NS-2. The simulation results have shown that devices using the APSM can improve energy efficiency by 115% at most compared with the ones using the standard PSM. The benefit of adaptive beacon interval and listening intervals is significant, while the improvement due to the adaptive backoff timer is minor. The improvement of the APSM over the PSM is more significant when the network traffic level decreases and the ratio of idle power to sleeping power increases. Additionally, the APSM increases the delay of data frames within a limited range, which does not bring any bad effect on network throughput.

To explore the key antibiofilm components of green Sichuan pepper essential oil (GPEO) against the spoilage microorganism Bacillus amyloliquefaciens and their intracellular targets, a molecular structure database of GPEO components and a collection of the molecule structures of target proteins related to the biofilm formation of B. amyloliquefaciens were created based on related literature data, and the CB-DOCK2 servicer was used to perform molecular docking of the active components of GPEO to biofilm formation-related target proteins. Furthermore, the key antibiofilm components of GPEO were selected based on their docking affinity and their potential targets were explored. Finally, in vitro experiments and crystal violet staining were conducted to confirm the antibiofilm effects of two key active components of GPEO, caryophyllene oxide and β-caryophyllene, against B. amyloliquefaciens. Molecular docking results showed that 24 volatile components of GPEO had different affinities to 58 targets associated with the biofilm formation of B. amyloliquefaciens, among which β-caryophyllene and caryophyllene oxide could tightly bind to ComP and RapC through intermolecular forces such as hyperconjugation, hydrophobic interaction and van der Waals force, forming a stable conformation. In vitro experiments showed that the minimal inhibitory concentrations (MICs) of caryophyllene oxide and β-caryophyllene against the biofilm of B. amyloliquefaciens were 6.0 and 2.0 mg/mL, respectively. Both compounds interfered with the swimming motility of this bacterium, reduced the initial cell adhesion and auto-aggregation ability, and altered the cell surface hydrophobicity. These results provide feasible strategies to help decipher the intracellular molecular mechanisms related to the biological activity of plant essential oil.

In recent years, with the continuous development of human exploration of the natural world, there has been a growing demand across various fields for robots capable of free movement in diverse environments. In this study, we address the issue of compliant control for a hexapod robot in diverse environments and propose a novel control method based on an adaptive impedance model for position control. Our approach enables the hexapod robot to stabilize foot force on complex terrains while preserving balance and body height. Specifically, we analyze the algorithm's parameters and stability by establishing the hexapod robot's structural and impedance control models. To tackle this challenge, we introduce an adaptive impedance control algorithm that estimates environmental parameters using Lyapunov's asymptotic stability theorem and achieves tracking of actual foot‐end forces to desired foot forces. Furthermore, to ensure body stability and height, we incorporate attitude feedback and body feedback. Experimental results from foot force control experiments conducted on a multilegged robot demonstrate that our proposed algorithm enhances the adaptability and robustness of the robot. This research holds significant implications for the stable control of hexapod robots in complex environments and has promising practical applications. [ABSTRACT FROM AUTHOR]

This study investigated the purification of pollutants in runoff rainwater by constructing a micro-ecosystem using waste-activated sludge (WAS) and riverbed sludge (RBS) as inoculums in combination with pervious concrete. The research results showed that the best hydraulic retention time (HRT) was 9 h. The COD and ammonia nitrogen (NH4+-N) removal of the waste-activated sludge ecosystem (WASE) was 62.67% and 71.21%, respectively, while the riverbed sludge ecosystem (RBSE) showed COD and NH4+-N removal percentages of 46.05% and 66.55%, respectively. The analysis of the genetic metabolism of microbial genes showed that the system was microbially enhanced with extensive and diverse populations. At the phylum level, the microorganisms responsible for degrading organic matter were mainly Firmicutes and Actinobacteriota. At the genus level, the Trichococcus genus was dominant in the WASE, while the Dietzia, norank_f__Sporomusaceae and norank_f__norank_o__norank_c__BRH-c20a genera were the central bacterial populations in the RBSE. The proliferation of phylum-level bacteria in the WASE was relatively large, and the genus-level bacteria demonstrated a better removal efficiency for pollutants. The overall removal effect of the WASE was better than that of the RBSE. The application analyses showed that a WASE is capable of effectively accepting and treating all rainfall below rainstorm levels and at near-full rainstorm levels under optimal removal efficiency conditions. This study innovatively used wastewater plant waste-activated sludge combined with pervious concrete to construct a micro-ecosystem to remove runoff rainwater pollutants. The system achieved pollutant removal comparable to that of pervious concrete modified with adsorbent materials. An effective method for the collection and pollutant treatment of urban runoff rainwater is provided. [ABSTRACT FROM AUTHOR]

This study investigates the performance of sludge-added pervious concrete (SPC) at different curing temperatures by replacing some of the cement with activated sludge (AS). The results reveal that the incorporation of AS into pervious concrete had a favorable impact. At a curing temperature of 30 °C, the 28-day compressive strength and specific surface area reached 20.8 MPa and 9.14 m2/g, respectively, representing a 60% and 98.7% increase, in comparison to conventional concrete. Furthermore, the addition of AS to the concrete results in a notable reduction in the concentration of chemical oxygen demand (COD) in surface runoff water. The maximum rate of COD removal observed was 55.6%. A mechanism study revealed that the strength of concrete increased due to the reaction between reactive SiO2 in AS and CaO in the aggregate. At a temperature of 30 °C, the microorganisms in the activated sludge fermentation process exhibit a higher production rate of fermentation gas, resulting in a greater escape of gas and an increase in the number of micropores in the permeable concrete. This leads to an enhanced specific surface area, which in turn exhibits a superior adsorption effect on COD. [ABSTRACT FROM AUTHOR]

Polyurethane sponge particles were employed as bio-immobilized cell carriers for dark fermentation hydrogen production with heating-treated cow dung inoculum from epipremnum aureum waste and kitchen waste. This study explored the performance changes of batch dark fermentation hydrogen production systems under different influent substrates. Different influent total solids concentration and substrate types both had a large effect on the efficiency of the biological hydrogen production process. Based on the combined analysis of hydrogen production efficacy, VFA, and energy conversion efficiency, the optimal influent total solids concentration was 2 g/L and 10 g/L for epipremnum aureum waste and kitchen waste, respectively. For the epipremnum aureum waste, the energy conversion efficiency was 13.6% and the metabolic type was mixed fermentation at a total solids concentration of 2 g/L. For kitchen waste, the energy conversion efficiency was 14.4% and the metabolic type was ethanol/acetic fermentation at a total solids concentration of 10 g/L. The results indicate that epipremnum aureum waste and kitchen waste can be used as substrates for dark fermentation hydrogen production, and kitchen waste performed better than epipremnum aureum waste at the same influent total solids concentration. Compared to other nutrients, both epipremnum aureum waste and kitchen waste also showed better hydrogen production efficacy and energy conversion efficiency. The study can provide a more economical and efficient method for residential household waste recycling. [ABSTRACT FROM AUTHOR]

[Objective] The effects of quinoa sowing date and density on soil nutrients, enzyme activities and microbial community structure were analyzed, and the optimal sowing date and sowing density of quinoa in Gannan area were determined, aiming to provide a theoretical basis and scientific reference for the adjustment of quinoa cultivation system and the promotion of quinoa industry. [Method] Using quinoa variety 'Longquinoa No. 5' as the material, a two-factor random block design was adopted, and two factors were set, including early sowing (sowing on May 15, E) and late sowing (sowing on June 24, L), and low density (1.2X104 plants/hm², D1), medium density (1.6X104 plants/hm², D2) and high density (2.0X104 plants/hm², D3), a total of 6 treatments, namely early sowing low density (ED1), early sowing medium density (ED2), early sowing high density (ED3), late sowing low density (LD1), late sowing medium density (LD2) and late sowing low density (LD3), the yield and its constituent factors of different treatments of quinoa were analyzed, and the rhizosphere soil pH of different treatments was determined. Nutrient content and soil enzyme activity, Illumina-HiSeq high-throughput sequencing technology was used to analyze the composition and diversity of bacterial community in rhizosphere soil of quinoa under different treatments, and finally the correlation between soil pH and nutrient content, relative abundance of bacterial community and enzyme activity was analyzed. [Result] Sowing date and density had significant effects on quinoa yield and its constituent factors. There was no significant difference in main panicle length among the treatments. Among the six treatments, the effective branch number and 1 000-grain weight of quinoa in LD1 treatment were the highest, and the total yield of ED2 and ED3 treatments was higher. Sowing date and density had no significant effect on soil pH in the rhizosphere of quinoa, but had a significant effect on soil nutrient content and enzyme activity. At the same density, the contents of total phosphorus, total potassium, total nitrogen and organic matter in the rhizosphere soil of late sowing quinoa were generally higher than those in the early sowing treatment, both at the branching stage and at the grain-filling stage. At the same density, the activities of catalase, sucrase and urease in the rhizosphere soil of late sowing quinoa at the branching stage were generally higher than those in the early sowing treatment, while the alkaline phosphatase in the early sowing treatment was lower than that in the late sowing treatment, and the catalase and alkaline phosphatase activities in the rhizosphere soil of late sowing quinoa at the grain filling stage were generally lower than those in the early sowing treatment, and the sucrase activities in the late sowing treatment were higher than those in the early sowing treatment. Sowing date and density had significant effects on the bacterial community structure of quinoa rhizosphere soil.In the branching stage, the average Shannon index and Simpson index of ED2 treatment were the highest, and the Chao1 index of LD2 treatment was the highest, and the coverage index of ED3 treatment was the highest. The results of correlation analysis showed that soil nutrient content and enzyme activity were significantly correlated with soil bacterial community structure, among which soil urease activity was significantly positively correlated with available phosphorus content, catalase activity was significantly positively correlated with available potassium content, soil sucrase was significantly positively correlated with total nitrogen content, catalase activity was significantly positively correlated with actinomycetes, urease activity was significantly positively correlated with Proteobacteria, and sucrase activity was significantly positively correlated with Blastomonas. [Conclusion] In the high-altitude cold areas of Gansu Province, the sowing date and density had significant effects on the yield of quinoa, its rhizosphere soil nutrient content, enzyme activity and bacterial community, and the sowing time of quinoa in this area was mid-May and the sowing density was (1.6-2.0)X104 plants/hm². [ABSTRACT FROM AUTHOR]

The impact of house prices rising on urban labor costs has typical heterogeneity and lag effects, but there is little literature on it. Based on the panel data of 283 prefecture level cities from 2001 to 2017, we constructed panel model considering lag effect and threshold effect. The results show that lag one period of housing price has significant positive impact on urban labor costs, with the increase of housing prices, the effect of pushing up the current labor costs is gradually increasing. So, this impact has obvious lag effect and threshold effect. Through grouped regression to test heterogeneity effect, at the regional level, the heterogeneity of the impact is more significant. The more developed the economy is, the greater the pushing effect of house prices on labor costs. [ABSTRACT FROM AUTHOR]