This paper is concerned with a novel Lyapunovlike functional approach to the stability of sampled-data systems with variable sampling periods. The Lyapunov-like functional has four striking characters compared to usua...This paper is concerned with a novel Lyapunovlike functional approach to the stability of sampled-data systems with variable sampling periods. The Lyapunov-like functional has four striking characters compared to usual ones. First, it is time-dependent. Second, it may be discontinuous. Third, not every term of it is required to be positive definite. Fourth, the Lyapunov functional includes not only the state and the sampled state but also the integral of the state. By using a recently reported inequality to estimate the derivative of this Lyapunov functional, a sampled-interval-dependent stability criterion with reduced conservatism is obtained. The stability criterion is further extended to sampled-data systems with polytopic uncertainties. Finally, three examples are given to illustrate the reduced conservatism of the stability criteria.展开更多
Hydrothermal carbonization of animal manure is being increasingly recognized as a green process for hydrochar production.Temperature obviously affects the properties of hydrochar especially with respect to carbon rete...Hydrothermal carbonization of animal manure is being increasingly recognized as a green process for hydrochar production.Temperature obviously affects the properties of hydrochar especially with respect to carbon retention and stability.These properties determine the carbon sequestration potential of hydrochar but related researches are limited.In this study,chicken,dairy,and swine manures were collected and hydrothermal carbonized under different temperature conditions,aiming to study the fuel characteristics,carbon retention,and stability of hydrochar influenced by temperature.Results show that high temperature led to low yield and declined H/C,O/C,and volatile matter of hydrochar.While high temperature caused high fixed carbon,fuel ratio,and heating value of hydrochar,indicating that animal manure hydrochar can be adopted as an alternative of fuel.After hydrothermal carbonization,less than half of carbon from animal manure was retained in hydrochar:22.70%-46.71%for chicken manure,39.36%-49.72%for dairy manure,and 36.24%-64.21%for swine manure.The carbon retention decreased with the increase of temperature.Conversely,high temperature improved the aromatic and strengthened the resistance to thermal oxidation of hydrochar,which was evidenced by FTIR and TGA analysis.Moreover,the carbon sequestration capacity of animal manure hydrochar was less than a third of total carbon(originated from animal manure)and relatively low temperature(no more than 250℃)was beneficial to produce hydrochar for carbon sequestration.展开更多
基金This research was supported by the Science Foundation No. 2011FZ 178, 2011FZ 180, 2014HD004, 14C26215303260 and National Natural Science Foundation of China （NSFC） No. 31260073, 31340019, 31160412, 41361056.
基金supported by the National Natural Science Foundation of China(61374090)the Program for Scientific Research Innovation Team in Colleges and Universities of Shandong Provincethe Taishan Scholarship Project of Shandong Province
文摘This paper is concerned with a novel Lyapunovlike functional approach to the stability of sampled-data systems with variable sampling periods. The Lyapunov-like functional has four striking characters compared to usual ones. First, it is time-dependent. Second, it may be discontinuous. Third, not every term of it is required to be positive definite. Fourth, the Lyapunov functional includes not only the state and the sampled state but also the integral of the state. By using a recently reported inequality to estimate the derivative of this Lyapunov functional, a sampled-interval-dependent stability criterion with reduced conservatism is obtained. The stability criterion is further extended to sampled-data systems with polytopic uncertainties. Finally, three examples are given to illustrate the reduced conservatism of the stability criteria.
基金the support of the Anhui Science and Technology Major Project(Grant No.201903a06020023)the Natural Science Research Project of Colleges and Universities in Anhui Province(Grant No.KJ2020A0049)+1 种基金the Anhui Province University Top Talent Funding Project(Grant No.gxbjZD2021069)the Commissioned R&D Project(Grant No.ZHEP2021001,No.BOFA202007).
文摘Hydrothermal carbonization of animal manure is being increasingly recognized as a green process for hydrochar production.Temperature obviously affects the properties of hydrochar especially with respect to carbon retention and stability.These properties determine the carbon sequestration potential of hydrochar but related researches are limited.In this study,chicken,dairy,and swine manures were collected and hydrothermal carbonized under different temperature conditions,aiming to study the fuel characteristics,carbon retention,and stability of hydrochar influenced by temperature.Results show that high temperature led to low yield and declined H/C,O/C,and volatile matter of hydrochar.While high temperature caused high fixed carbon,fuel ratio,and heating value of hydrochar,indicating that animal manure hydrochar can be adopted as an alternative of fuel.After hydrothermal carbonization,less than half of carbon from animal manure was retained in hydrochar:22.70%-46.71%for chicken manure,39.36%-49.72%for dairy manure,and 36.24%-64.21%for swine manure.The carbon retention decreased with the increase of temperature.Conversely,high temperature improved the aromatic and strengthened the resistance to thermal oxidation of hydrochar,which was evidenced by FTIR and TGA analysis.Moreover,the carbon sequestration capacity of animal manure hydrochar was less than a third of total carbon(originated from animal manure)and relatively low temperature(no more than 250℃)was beneficial to produce hydrochar for carbon sequestration.
