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Regarding to the complex chaotic non-linear behaviour in nature and the impossibility of their accurate modelling with current chaotic models, the development of Cascade Hyper-Chaotic System is necessary. Therefore, in this paper, new cascade hyper chaotic systems are proposed. Cascade hyper-chaotic systems have more parameters than the above-mentioned systems, and in most cases, they show more complex behaviour. On the other hand, due to the complexity of these systems and their high parameters, the identification of this kind of systems is difficult. For this reason, a new Adaptive Chaotic Grey Wolf Optimisation algorithm is presented in this article in order to estimate the parameters of these systems. Numerical simulations have been performed on the above-mentioned systems of Lu-Chen, Chen-Lorenz and Lu-Lorenz cascading. The results show that the systems have more complex behaviour than the seed systems and the proposed grey wolf algorithm is also an effective tool for estimating the parameter of the above-mentioned cascade Hyper-Chaotic System. [ABSTRACT FROM AUTHOR]

By establishing the characterization model of variable sectional area distributions, a cascade design method of torque converter based on variable sectional area distribution is proposed. Additionally, the corresponding collaborative design method for multi-impeller turbomachinery is proposed and further studied. The design cases of the impellers with different sectional area distributions are constructed through the response surface method, and the corresponding hydrodynamic characteristics are further compared and explored. However, the design of different impeller sectional area distributions for the optimal performance of the whole turbomachinery requires the collaborative design of each component's distribution results rather than a simple combination of such optimal impeller's area distribution result. Thus a collaborative design strategy is proposed, which can improve the pump's capacity performance by 8.83%, the maximum torque ratio performance can also increased by 6.33%, which proves that such a collaborative design method is an effective optimization design approach to improve the performance of the torque converter without altering the overall dimension. The experimental results of the optimal prototype show that the torque ratio reaches 5.33% higher than the original value, which indicates that such a collaborative optimization method for multi-impeller turbomachinery is effective and reliable. [Display omitted] • Sectional area distribution is critical for multi-impeller turbomachinery. • Proper area distribution can enhance curative effect for stamping turbomachinery. • The raising-area pump and even-area turbine contribute to torque ratio performance. • Collaborative optimization of area is effective for torque converter performance. [ABSTRACT FROM AUTHOR]

The golden mussel (Limnoperna fortunei) is an invasive bivalve that has established itself in several South American river systems, impacting ecosystem functioning. Reservoir cascades provide their larvae with the means of rapid dispersal, but the relationship between environmental variables and larval stage structure remains unclear. In this study, the density of three L. fortunei larval stages and quantitative detection using DNA are analyzed in a cascade of five reservoirs in the upper Uruguay River Basin and associated with spatiotemporal variation in environmental parameters. The analysis of L. fortunei eDNA presence and absence in freshwater systems appears to be a valuable mapping tool; however, no significant link was found between the eDNA magnitude and the overall larval density. The increase in larval density was related to the fluctuation of environmental parameters over a year, with the highest average larval densities observed in the CN and ITA reservoirs, though no significant difference was observed between the five reservoirs, where D-shaped larvae predominated. During winter, larval density decreased significantly, however, other variables also contribute to species activity and development in the upper Uruguay River Basin reservoirs and may be considered limiting factors. The relationships between environmental parameters were evaluated using a multivariate model. The interaction between reservoir area and precipitation, water temperature, electrical conductivity, and dissolved oxygen had a significant effect on larval density but showed specific influences on each larval stage. Any increase in density was regulated by dissolved oxygen and electrical conductivity content at all larval stages. Furthermore, total phosphorus affected the density of F1 and F3 larvae. The interaction between reservoir area and precipitation, nitrate content, phosphate concentrations, and water temperature had the most influence on the density of F2 and F3 larval stages; the F1 stage was mainly affected by calcium concentrations. The isolated effect of precipitation also contributed to the density of F2 and F3 larvae. Our findings shed light on the interaction between different phases of golden mussel larvae and the main nutrients found in reservoirs, which may be a determining factor in the rise in density of the non-native species in these systems. [ABSTRACT FROM AUTHOR]

By establishing the characterization model of variable sectional area distributions, a cascade design method of torque converter based on variable sectional area distribution is proposed. Additionally, the corresponding collaborative design method for multi-impeller turbomachinery is proposed and further studied. The design cases of the impellers with different sectional area distributions are constructed through the response surface method, and the corresponding hydrodynamic characteristics are further compared and explored. However, the design of different impeller sectional area distributions for the optimal performance of the whole turbomachinery requires the collaborative design of each component’s distribution results rather than a simple combination of such optimal impeller’s area distribution result. Thus a collaborative design strategy is proposed, which can improve the pump’s capacity performance by 8.83%, the maximum torque ratio performance can also increased by 6.33%, which proves that such a collaborative design method is an effective optimization design approach to improve the performance of the torque converter without altering the overall dimension. The experimental results of the optimal prototype show that the torque ratio reaches 5.33% higher than the original value, which indicates that such a collaborative optimization method for multi-impeller turbomachinery is effective and reliable.

Electrocatalytic N2 reduction reaction (eNRR) has been deemed as an alternative approach to the Haber‐Bosch (H‐B) process for ammonia (NH3) production, but it remains a huge challenge. Here jet plasma oxidation of N2 is reported in air into NOx and subsequently NO2− coupling with electrochemical NO2− reduction reaction (pN2─eNO2−RR) over PdNi alloying nanoparticles on N‐doped carbon nanotubes (PdNi/N‐CNTs) for NH3 synthesis. The results demonstrate that the jet plasma reactor possesses excellent gas reforming capacity to achieve the largest NO2− yield rate of 30.46 mmol h−1 with a low energy consumption of 2.66 kWh molN−1. For subsequent eNO2−RR, PdNi/N‐CNTs can afford an NH3 yield of 34.96 mg h−1 mgcat.−1 and a faradaic efficiency (FE) of 98.21% at −0.38 and 0.02 V (vs RHE), respectively. In situ spectroscopic characterizations combined with theoretical calculations unveil that PdNi/N‐CNTs provide Pd and Ni dual active sites, enabling NO2− activation on the Ni site and active H* provision on the Pd site to facilitate eNO2−RR. A cascade pN2‐eNO2−RR system is constructed for sustainable NH3 production, achieving a stable NH3 yield rate of 25.56 mmol h−1, an average FE >85%, as well as NOx to NH3 conversion efficiency of 44.62% at constant ampere‐level current with finally collection of gram‐level (NH4) 2SO4 product. [ABSTRACT FROM AUTHOR]

The characteristics of autonomous underwater vehicles include nonlinearity, strong coupling, multiple inputs and multiple outputs, uncertainty, strong disturbance, underdrive, and multiple constraints. Autonomous underwater vehicle cluster systems are associated with large-scale complex dynamic systems through local perception or network communication, which have the structural characteristics of "complex dynamic + association topology + interaction rules". To solve the problem of formation trajectory tracking of underactuated autonomous underwater vehicles, a controller was designed on the basis of an improved nonlinear backstepping algorithm, cascade system theory, and the Lyapunov direct method. In this design, the formation is determined from the actual trajectory of the leader autonomous underwater vehicle. The formation control rate is determined using the backstepping method and Lyapunov theory. Nonlinear disturbance observers were added to ensure that the trajectory error of the formation control could be quickly reduced in a real case with interference. The stability and effectiveness of this method were verified through simulation experiments. The robustness of the control algorithm was verified using two simulation cases, and the simulation results show that the proposed control method can maintain the expected formation. [ABSTRACT FROM AUTHOR]

During the last decade, many industrial and medical applications have shown a requirement for low-temperature-cooling usage (from −40 to −80 °C), which cannot be efficiently obtained via the conventional refrigeration systems usually employed for medium-temperature applications (from 0 to −40 °C). A proper ultra-low-temperature (ULT) refrigeration system design is essential to achieve the desired output. The performance can be maximised via the suitable selection of the configuration and refrigerant for a specific temperature range. This work contributes a detailed overview of the different systems and refrigerants used in ultra-low-temperature applications. Different systems, such as single-stage vapour compression, multi-stage, cascade, auto-cascade, and air refrigeration cycles, are presented and discussed. An energy analysis is then carried out for these systems identifying the optimal system design and refrigerant selection to achieve the highest performance. This paper aims to provide the reader with a comprehensive background through an exhaustive review of refrigeration systems suitable for ultra-low-temperature applications. The effectiveness of these systems is proven numerically, mainly based on the temperature level and purpose of the application. [ABSTRACT FROM AUTHOR]

• Cascade high-temperature heat pump was modeled and simulated using MATLAB. • New zeotropic refrigerant mixtures of R744, R600 and R601 were introduced. • The system was designed to produce hot water above 100 °C. • The system was proved to be suitable for high-temperature heating with a COP of 4.5. • Substantial improvement was noted compared to published results. Many Industrial applications demand clean, high-temperature heating to meet their requirements. High coefficient of performance (COP) and low-pressure ratios are the keys to the development of cascade heat pump systems. The present work investigates the high-temperature heat pump (HTHP) using a two-stage cascade refrigeration system to produce hot water of more than 100 °C and up to 118 °C. MATLAB was used to design and simulate the HTHP model. The results of the simulation were analyzed to explore the production of high-temperature water. The composition of mixed natural zeotropic refrigerants, such as CO 2 +butane and CO 2 +pentane mixtures were introduced in the Low-stage (LS) and High-stage (HS) cycle, respectively. Water was used as the secondary fluid and as a heat source with a temperature range of 10–50 °C. The temperature lift, heating capacity, heat sink, hot water delivery temperatures, HS, LS, and total COP, were investigated to identify the performance of the system and expounded in detail. The maximum heating capacity of the system can reach 205 kW. The system's total COP was 4.5, one of the top-notch results in this HTHP research. Overall, the system's use of natural refrigerants, highly efficient performance, and high-temperature water heating abilities make the investigation of high importance. A comparison of the present and published results indicates a substantial improvement of 36% of the total COP. The pressure levels in both LS and HS indicate that the system pressure requirements are in good agreement to operate the system effectively with excellent performance. [ABSTRACT FROM AUTHOR]

Quadrotors play a significant role in our lives and are transforming our lives. Transporting cable-suspended loads is an unavoidable quadrotor application trend and a hot research topic in the control field. Nonetheless, the load swing and unpredictability pose significant challenges to the quadrotor's stability. In this paper, an anti-swing controller with an inner-outer control strategy for the quadrotor-slung load transportation system is presented. To facilitate the controller design, the outer position dynamics are restructured in the form of cascades. Then, a virtual controller is created to force the underactuated states to the dynamic surface to ensure the position subsystem's stability. To improve robustness, an adaptive law is used to eliminate the effects of uncertain cable length. Lastly, a dynamic surface controller for the inner attitude subsystem is presented to drive the actual force to the virtual force. It is demonstrated that the control strategy can stabilize the quadrotor despite mass and cable length uncertainties. Comparative results are provided to demonstrate the efficacy and durability of the proposed method. [ABSTRACT FROM AUTHOR]

In this study, we propose a data-driven design method for a cascade control system with inner and outer control loops. First, the input–output response of a controlled plant, which varies with the controller parameters of a fixed-structure inner-outer control law, is estimated directly from open-loop input–output data. Next, based on the estimated response, the controller parameters are optimized to minimize the difference between a reference model with a controlled closed-loop system. In the proposed method, the response of a fictitious reference input, which varies with the controller parameters, is estimated, and then the closed-loop response is estimated. Therefore, a closed-loop input–output data is not required, and the controller parameters are determined directly from an open-loop input–output data. Furthermore, the time constant of a reference model is also optimized so as to reduce the control error. The proposed method is compared with both conventional single-loop and cascade data-driven methods by means of numerical examples. • A data-driven cascade control system with inner and outer control loops is proposed. • Input-output response which varies with controller parameters is estimated. • The controller parameters that minimize a model reference problem are obtained. • The time constant of a reference model is also optimized. • The proposed method is compared with conventional single-loop and cascade methods. [ABSTRACT FROM AUTHOR]

The characteristics of autonomous underwater vehicles include nonlinearity, strong coupling, multiple inputs and multiple outputs, uncertainty, strong disturbance, underdrive, and multiple constraints. Autonomous underwater vehicle cluster systems are associated with large-scale complex dynamic systems through local perception or network communication, which have the structural characteristics of “complex dynamic + association topology + interaction rules”. To solve the problem of formation trajectory tracking of underactuated autonomous underwater vehicles, a controller was designed on the basis of an improved nonlinear backstepping algorithm, cascade system theory, and the Lyapunov direct method. In this design, the formation is determined from the actual trajectory of the leader autonomous underwater vehicle. The formation control rate is determined using the backstepping method and Lyapunov theory. Nonlinear disturbance observers were added to ensure that the trajectory error of the formation control could be quickly reduced in a real case with interference. The stability and effectiveness of this method were verified through simulation experiments. The robustness of the control algorithm was verified using two simulation cases, and the simulation results show that the proposed control method can maintain the expected formation.

There is a great demand for clean, high-temperature heating in industries. The present work demonstrates the modeling and analysis of a high-temperature heat pump (HTHP) using a two-stage cascade refrigeration system with newly developed refrigerant mixtures. Environment-friendly CO2/butane and CO2/pentane mixtures were introduced in the Low-stage (LS) and High-stage (HS) cycles, respectively. The model was built in MATLAB and explored the possibilities of high-temperature heating. A heating source temperature of 10 to 50 °C was considered as the system's input. The HTHP was designed to deliver hot water at a temperature above 115 °C. The performance of the system was investigated in terms of the heat sink and hot water temperatures, temperature lift, heating capacity, LS, HS, and total system’s coefficient of performance (COP), volumetric and isentropic efficiencies, and discussed. The analysis indicated that the system could deliver high-temperature water with a temperature lift of 70 °C. Mixtures of 5% CO2/ 95% butane and 5% CO2/ 95% pentane exhibit excellent thermo-physical properties making them suitable for high-temperature heating applications with high COP. For instance, such mixtures obtain the system's COP and heating capacity of 3.6 and 201.5 kW, respectively for the heat sink temperature of 116.7 °C. It shows an improvement of 20% compared to pure fluids. Also, the heat sink temperature could reach up to 181 °C when the CO2 composition in the refrigerant mixtures is 20%. The volumetric (0.72–0.87) and isentropic (0.61–0.71) efficiencies of the compressor were studied and displayed.

We consider a two-station cascade system in which waiting or externally arriving customers at station 1 move to the station 2 if the queue size of station 1 including an arriving customer itself and a customer being served is greater than a given threshold level c 1 ≥ 1 and if station 2 is empty. Assuming that external arrivals are subject to independent renewal processes satisfying certain regularity conditions and service times are i.i.d. at each station, we derive necessary and sufficient conditions for a Markov process describing this system to be positive recurrent in the sense of Harris. This result is extended to the cascade system with a general number k of stations in series. This extension requires certain traffic intensities of stations 2 , 3 , ... , k - 1 for k ≥ 3 to be defined. We finally note that the modeling assumptions on the renewal arrivals and i.i.d. service times are not essential if the notion of the stability is replaced by a certain sample path condition. This stability notion is identical with the standard stability if the whole system is described by the Markov process which is a Harris irreducible T-process. [ABSTRACT FROM AUTHOR]

Copyright of Control Theory & Applications / Kongzhi Lilun Yu Yinyong is the property of Editorial Department of Control Theory & Applications and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper considers an m-station cascade system with renewal arrival processes and general service time distributions. Miyazawa and Morozov (Queueing Syst 100:225–227, 2022a; Stability of a cascade system with two stations and its extension for multiple stations, 2022b. arXiv:2203.14294v1) formulated a conjecture on the stability of this cascade system. In this paper, we show that this conjecture is not true for m ≥ 3 . We also show that when m ≥ 3 , the stability condition is not determined solely by the moments of the interarrival and service times, but also depends on their distributions. In addition, we provide the necessary and sufficient condition for the stability of this cascade system by modifying a result of Miyazawa and Morozov (2022). [ABSTRACT FROM AUTHOR]

The highest thermal energy for phase change material (PCM) is stored/discharged with unsubstantial temperature changes during the isothermal phase transition. However, the convective latent heat storage system uses temperature differences between the thermal load and working fluid. It restricts the temperature operation of the storage system since the temperature of the working fluid is limited by the melting temperature of PCM. To overcome the related issue, the present study proposes a configuration for small-scale cascade latent heat storage using three different melting points of the phase change materials. The three-stage cascade system is occupied by paraffin, RT80, and high-density polyethylene for the 1st, 2nd and 3rd storage tanks with melting temperatures of 60.9 °C, 79.6 °C and 115.4 °C, respectively. The overall system demonstrates a better performance than a single tank, with an average temperature variation of 42.9 °C and 34.5 °C during charging and discharging. The effect of partial phase change can be decreased where the power effective for discharging decreases by only 6.3% while the power effective during charging increases by 18.2%. It proves that using a multistage cascade system with gradual melting temperature PCM allows higher performance for a latent heat storage system.

For quadrotor control applications, it is necessary to rely on attitude angle changes to indirectly achieve the position trajectory tracking purpose. Several existing literature studies omit the non-negligible attitude transients in the position controller design for this kind of cascade system. The result leads to the position tracking performance not being as good as expected. In fact, the transient behavior of the attitude tracking response cannot be ignored. Therefore, the closed-loop stability of the attitude loop as well as the position tracking should be considered simultaneously. In this study, the flight controller design of the position and attitude control loops is presented based on an integral backstepping control algorithm. This control algorithm relies on the derivatives of the associated virtual control laws for implementation. Examining existing literature, the derivatives of the virtual control law are realized approximated by numerical differentiations. Nevertheless, in practical scenarios, the numerical differentiations will cause the chattering phenomenon of control signals in the presence of unavoidable measurement noise. The noise-induced control signals may further cause damage to the actuators or even diverge the system response. To address this issue, the analytic form for the derivative of the virtual control law is derived. The time derivative virtual control law is analyzed and split into the disturbance-independent compensable and disturbance-dependent non-compensable terms. By utilizing the compensable term, the control chattering due to the differentiation of the noise can be avoided significantly. The simulation results reveal that the proposed control algorithm has a better position tracking performance than the traditional dual-loop control scheme. Meanwhile, a relatively smooth control signal can be obtained for a realistic control algorithm realization. Simulations are provided to illustrate the position tracking issue of a quadrotor and to demonstrate the effectiveness of the proposed compromised control scheme. [ABSTRACT FROM AUTHOR]

Summary: A data‐driven design method for a cascade control system is proposed. The cascade control system consists of inner and outer loops, where the control interval of the outer loop is an integer multiple of the inner loop; hence, the system is a dual‐rate system. In the proposed method, controllers in the inner and outer loops are designed based on one‐shot data. In such a dual‐rate cascade system, since the controllers are designed using different data‐rate signals, the lifting technique is applied to align the dual‐rate data. To show its effectiveness, the proposed method is compared with a conventional single‐rate cascade control method, and numerical simulations and experiments are presented to examine servo and regulation performance. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) driven endoplasmic reticulum (ER) stress is highly promising for tumor therapy but restrained by the nondurable introduction and limited lifetime of oxidative species. Here, a therapeutic nanosystem with sustainable ROS generation ability was developed by accommodating luminol derivatives (L012) in hyaluronic acid‐modified metal‐organic frameworks of Fe3+ and porphyrin ligand (TCPP). After particle accumulation in the tumor, ∙OH radicals from Fe3+ sites catalyzed conversion of H2O2 can react with confined L012 transducers to generate chemiluminescence (CL). Because of the distance constraints, the CL energy was significantly extracted (96%) by adjacent TCPP and further activate oxygen to long‐lifetime singlet oxygen (1O2), whose yield can be further boosted by the catalase‐like activity of the frameworks. By regulating the substrate consumption through energy conversion, the cascade process resulted in increased ROS levels (2.4‐fold) and sustainable oxidation (24 h), which induced continuously accumulated ER stress, high autophagic levels, and amplified lethality against the tumor. This work opens a new avenue to explore reticular nanostructures with complementarily arranged and synergistically spaced conversion units in advancing ROS therapy. [ABSTRACT FROM AUTHOR]

Improving the efficiency of solar energy utilization systems is of great importance in solar energy utilization. Near-field thermophotovoltaic cells can achieve a high power density and, therefore, efficiently utilize radiative heat transfer. An efficient spectrum-splitting solar energy utilization system based on near- and far-field thermophotovoltaics was proposed. The input solar energy was divided by the splitter, and the two parts of the energy were utilized differently. The concentration ratio can determine the energy input of the system, which can affect the photoelectric conversion efficiency of the system. Further, the vacuum distance can modulate the near-field radiative heat transfer, thus significantly impacting system performance. Based on the fluctuation dissipation theorem and Maxwell's equations, a system model was constructed and calculated using the optimal design method, and the effects of these parameters were investigated. Moreover, the optimal efficiency was obtained under different operating conditions. The optimal cascade system efficiency reached 39.93 % at a concentration ratio of 3000, which was 15.59 % higher than that of a single photovoltaic system. Thus, this study proposes a method for the efficient utilization of solar energy. In addition, it provides guidance for the subsequent design and construction of spectrum-splitting cascade systems based on near- and far-field thermophotovoltaics. • Near- and far-field thermophotovoltaics are used for solar energy utilization. • The optimal operating condition of the system is obtained through calculation. • The cascade system offers remarkable efficiency advantages. • The system efficiency is significantly improved by spectrum-splitting technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • Developed a novel continuous-flow cascade photocatalytic system for elimination of SMX. • Tailored photoreactor design maximizes the photonic efficiency for SMX degradation. • System optimization achieved a high photocatalytic activity toward SMX removal. • The three-step cascade system achieved 80% SMX removal efficiency from hospital sewage. • The system achieved an electrical energy per order (E EO) value of 2.03 kWh/m3. In this study, we introduce a novel continuous-flow cascade photocatalytic system specifically designed to efficiently remove sulfamethoxazole (SMX) from hospital wastewater, addressing the critical need for sustainable pharmaceutical wastewater treatment. The system utilizes a carbon sponge-based TiO 2 photocatalyst synthesized via a hydrothermal process under mild conditions. The system's design incorporates multiple stages in a cascade configuration, meticulously optimized to enhance photocatalytic efficacy, thereby significantly improving the rate of SMX elimination while minimizing energy consumption. The study encompasses comprehensive characterization of the photocatalyst, including matching its absorption spectrum to the emission spectrum of the light source, as well as fine-tuning key operational parameters such as catalyst quantity, flow rates, and cascade configuration. Real-world application tests confirm the system's efficiency, achieving approximately 80 % SMX removal efficiency alongside a notable reduction in Chemical Oxygen Demand (COD) levels. Furthermore, the system's energy efficiency, as reflected by an Electrical Energy per Order (E EO) value of 7.53 kWh/m3, highlights its potential for scalable and sustainable wastewater treatment solutions. This study not only contributes significantly to the field of environmental catalysis but also represents a significant advancement in sustainable environmental management, offering a promising solution to the urgent challenge of pharmaceutical pollution in water sources. [ABSTRACT FROM AUTHOR]

Abstract Reactive oxygen species (ROS) driven endoplasmic reticulum (ER) stress is highly promising for tumor therapy but restrained by the nondurable introduction and limited lifetime of oxidative species. Here, a therapeutic nanosystem with sustainable ROS generation ability was developed by accommodating luminol derivatives (L012) in hyaluronic acid‐modified metal‐organic frameworks of Fe3+ and porphyrin ligand (TCPP). After particle accumulation in the tumor, ∙OH radicals from Fe3+ sites catalyzed conversion of H2O2 can react with confined L012 transducers to generate chemiluminescence (CL). Because of the distance constraints, the CL energy was significantly extracted (96%) by adjacent TCPP and further activate oxygen to long‐lifetime singlet oxygen (1O2), whose yield can be further boosted by the catalase‐like activity of the frameworks. By regulating the substrate consumption through energy conversion, the cascade process resulted in increased ROS levels (2.4‐fold) and sustainable oxidation (24 h), which induced continuously accumulated ER stress, high autophagic levels, and amplified lethality against the tumor. This work opens a new avenue to explore reticular nanostructures with complementarily arranged and synergistically spaced conversion units in advancing ROS therapy.

Carrageenan oligosaccharides have shown promising bioavailability and possess a variety of physiological activities, making them highly suitable for use in the food, pharmaceutical, and agricultural industries. The preferred method for producing carrageenan oligosaccharides is using various carrageenolytic enzymes, as it offers mild reaction conditions, high efficiency, and product specificity. However, there is still a lack of specific applications for using these enzymes to prepare odd-numbered carrageenan-oligosaccharides (OCOSs). Our previous research identified a more convenient route for simultaneously preparing OCOSs and 3,6-anhydro-D-galactose (D-AHG) using only two types of carrageenolytic enzymes: κ-carrageenase and exo-α-3,6-anhydro-D-galactosidase (D-ADAGase). In this study, we utilized a CipA-based self-assembly system to cascade κ-carrageenase CaKC16A and D-ADAGase ZuGH129A for one-step preparation of β/κ-carrapentaose, G-(DA-G4S) 2 , and D-AHG from degrading β/κ-carrageenan. This self-assembled enzyme, namely CipA-CaKC16A-ZuGH129A, can be easily obtained through a simple centrifugation process. The final optimized enzymatic process produced 0.74 g/L G-(DA-G4S) 2 and 0.13 g/L D-AHG. This cascade system of different types of carrageenolytic enzymes has the potential to achieve the preparation of various types of carrageenan oligosaccharides.

Copyright of Nuclear Safety is the property of Nuclear & Radiation Safety Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Most SARS-CoV-2 infected patients experience influenza-like symptoms of low or moderate severity. But, already in 2020 early during the pandemic it became obvious that many patients had a high incidence of thrombotic complications, which prompted treatment with high doses of low-molecular-weight heparin (LMWH; typically 150-300IU/kg) to prevent thrombosis. In some patients, the disease aggravated after approximately 10 days and turned into a full-blown acute respiratory distress syndrome (ARDS)-like pulmonary inflammation with endothelialitis, thrombosis and vascular angiogenesis, which often lead to intensive care treatment with ventilator support. This stage of the disease is characterized by dysregulation of cytokines and chemokines, in particular with high IL-6 levels, and also by reduced oxygen saturation, high risk of thrombosis, and signs of severe pulmonary damage with ground glass opacities. The direct link between SARS-CoV-2 and the COVID-19-associated lung injury is not clear. Indirect evidence speaks in favor of a thromboinflammatory reaction, which may be initiated by the virus itself and by infected damaged and/or apoptotic cells. We and others have demonstrated that life-threatening COVID-19 ARDS is associated with a strong activation of the intravascular innate immune system (IIIS). In support of this notion is that activation of the complement and kallikrein/kinin (KK) systems predict survival, the necessity for usage of mechanical ventilation, acute kidney injury and, in the case of MBL, also coagulation system activation with thromboembolism. The general properties of the IIIS can easily be translated into mechanisms of COVID-19 pathophysiology. The prognostic value of complement and KKsystem biomarkers demonstrate that pharmaceuticals, which are licensed or have passed the phase I trial stage are promising candidate drugs for treatment of COVID-19. Examples of such compounds include complement inhibitors AMY-101 and eculizumab (targeting C3 and C5, respectively) as well as kallikrein inhibitors ecallantide and lanadelumab and the bradykinin receptor (BKR) 2 antagonist icatibant. In this conceptual review we discuss the activation, crosstalk and the therapeutic options that are available for regulation of the IIIS. [ABSTRACT FROM AUTHOR]

Most SARS-CoV-2 infected patients experience influenza-like symptoms of low or moderate severity. But, already in 2020 early during the pandemic it became obvious that many patients had a high incidence of thrombotic complications, which prompted treatment with high doses of low-molecular-weight heparin (LMWH; typically 150-300IU/kg) to prevent thrombosis. In some patients, the disease aggravated after approximately 10 days and turned into a full-blown acute respiratory distress syndrome (ARDS)-like pulmonary inflammation with endothelialitis, thrombosis and vascular angiogenesis, which often lead to intensive care treatment with ventilator support. This stage of the disease is characterized by dysregulation of cytokines and chemokines, in particular with high IL-6 levels, and also by reduced oxygen saturation, high risk of thrombosis, and signs of severe pulmonary damage with ground glass opacities. The direct link between SARS-CoV-2 and the COVID-19-associated lung injury is not clear. Indirect evidence speaks in favor of a thromboinflammatory reaction, which may be initiated by the virus itself and by infected damaged and/or apoptotic cells. We and others have demonstrated that life-threatening COVID-19 ARDS is associated with a strong activation of the intravascular innate immune system (IIIS). In support of this notion is that activation of the complement and kallikrein/kinin (KK) systems predict survival, the necessity for usage of mechanical ventilation, acute kidney injury and, in the case of MBL, also coagulation system activation with thromboembolism. The general properties of the IIIS can easily be translated into mechanisms of COVID-19 pathophysiology. The prognostic value of complement and KKsystem biomarkers demonstrate that pharmaceuticals, which are licensed or have passed the phase I trial stage are promising candidate drugs for treatment of COVID-19. Examples of such compounds include complement inhibitors AMY-101 and eculizumab (targeting C3 and C5, respectively) as well as kallikrein inhibitors ecallantide and lanadelumab and the bradykinin receptor (BKR) 2 antagonist icatibant. In this conceptual review we discuss the activation, crosstalk and the therapeutic options that are available for regulation of the IIIS.

Stochastic resonance (SR) can realize bearing fault signal diagnosis by transferring noisy energy. In order to enhance the output response of the system and realize effective signal extraction, the nonlinear mass fluctuation SR system caused by nonlinear asymmetric dichotomous noise is cascaded to obtain the cascaded nonlinear mass fluctuation SR system. First, the output amplitude gain of the first-stage of the system is derived, and the influence of different parameters on it is explored; then the effects of different parameters of the cascaded system on the output amplitude gain and the output SNR are studied separately, which proves that the cascaded system can effectively double enhance the output response of the system; finally, the adaptive genetic algorithm is used to solve the difficulty of parameter adjustment, and the cascaded nonlinear mass fluctuation SR system is applied to the bearing fault diagnosis. The system proposed in this paper takes into account the effects of nonlinear asymmetric dichotomous noise and cascaded systems and performs waveform smoothing and double enhancement of the output signal. It can better extract fault signals and has effective engineering value. [ABSTRACT FROM AUTHOR]

When a converter is composed of cascaded system with another unknown converter, the optimal design of the converter is especially important owing to stability of the cascaded systems. Battery `s model is introduced to analysis. Battery converter's different work conditions are considered. Battery converter is the front stage when it discharges, and it is the rear one when it charges in a cascade DC system. From the view of impedance, it's good for the cascaded system stability to reduce output impedance of battery converter when the converter is the first stage. Another, increasing the converter's input impedance could improve the cascade system stability when the converter becomes the rear one. The battery equivalent circuit model is introduced as a key component of system. Battery bidirectional converter should act as the front or rear stage of cascaded system. Selection rules of LC filter are put forward according to analyzing the inductor and capacitor's effects on two conditions. The PI controller parameters' effects on impedance are analyzed to furnish the basis for the PI controller parameters selection. Finally, experiment is carried out to verify the correctness of the analyses.

For quadrotor control applications, it is necessary to rely on attitude angle changes to indirectly achieve the position trajectory tracking purpose. Several existing literature studies omit the non-negligible attitude transients in the position controller design for this kind of cascade system. The result leads to the position tracking performance not being as good as expected. In fact, the transient behavior of the attitude tracking response cannot be ignored. Therefore, the closed-loop stability of the attitude loop as well as the position tracking should be considered simultaneously. In this study, the flight controller design of the position and attitude control loops is presented based on an integral backstepping control algorithm. This control algorithm relies on the derivatives of the associated virtual control laws for implementation. Examining existing literature, the derivatives of the virtual control law are realized approximated by numerical differentiations. Nevertheless, in practical scenarios, the numerical differentiations will cause the chattering phenomenon of control signals in the presence of unavoidable measurement noise. The noise-induced control signals may further cause damage to the actuators or even diverge the system response. To address this issue, the analytic form for the derivative of the virtual control law is derived. The time derivative virtual control law is analyzed and split into the disturbance-independent compensable and disturbance-dependent non-compensable terms. By utilizing the compensable term, the control chattering due to the differentiation of the noise can be avoided significantly. The simulation results reveal that the proposed control algorithm has a better position tracking performance than the traditional dual-loop control scheme. Meanwhile, a relatively smooth control signal can be obtained for a realistic control algorithm realization. Simulations are provided to illustrate the position tracking issue of a quadrotor and to demonstrate the effectiveness of the proposed compromised control scheme.

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The aim of our study is to propose a theoretical model to analyze the energy efficient and environment friendly cascade system for various refrigerant pairs. In order to realize, the optimum cascade evaporation temperature (TOPT,CAS,E) which maximize the performance, COP values are determined for different refrigerant pairs of the system. After the optimization, two different cases have been investigated through a thermodynamic analysis to discover the best refrigerant pair for the system. Natural refrigerant CO2 is selected instead of R404A which has high Global Warming Potential (GWP) value for the low temperature cycle (LTC). On the other hand, synthetic refrigerants (R134a, R152a) and a natural refrigerant (NH3) are chosen for the high temperature cycle (HTC). In order to determine, an energy efficient and environmentally friendly cascade system, R134a/CO2, R152a/CO2 and NH3/CO2 refrigerant pairs are investigated in Case 1. On the other hand, R134a/R404A, R152a/R404A and NH3/R404A refrigerant pairs are investigated in Case 2. In calculations, the evaporation temperature (TE) is varied from -20oC to -40oC in LTC. The condensation temperature (TC) is considered to be between 30oC and 45oC in HTC. Mass flow rate requirements of systems for various refrigeration capacities (QEvap) are calculated for different refrigerant pairs. Moreover, the COPmax and total equivalent warming impact (TEWI) values of the system’s refrigerant pairs are evaluated and compared for various operating conditions.

In order to overcome the security weakness of the discrete chaotic sequence caused by small Lyapunov exponent and keyspace, a general chaotic construction method by cascading multiple high-dimensional isomorphic maps is presented in this paper. Compared with the original map, the parameter space of the resulting chaotic map is enlarged many times. Moreover, the cascaded system has larger chaotic domain and bigger Lyapunov exponents with proper parameters. In order to evaluate the effectiveness of the presented method, the generalized 3-D Hénon map is utilized as an example to analyze the dynamical behaviors under various cascade modes. Diverse maps are obtained by cascading 3-D Hénon maps with different parameters or different permutations. It is worth noting that some new dynamical behaviors, such as coexisting attractors and hyperchaotic attractors are also discovered in cascaded systems. Finally, an application of image encryption is delivered to demonstrate the excellent performance of the obtained chaotic sequences. [ABSTRACT FROM AUTHOR]

• Double-effect absorption/vapor-compression cascade cycle for high temperature lift. • High cooling capacities and COP s over wide operation range. • Low-temperature (−40°C) cooling for pulsed high-heat flux electronics. • Medium-temperature (5°C) cooling for low-heat flux loads and space-conditioning. • Parametric study over exhaust temperatures and heat rejection temperatures. A robust, high-performance, cascaded double-effect absorption/vapor-compression cycle with a high temperature lift was conceptualized and analyzed for a naval ship application. A double-effect LiBr–H 2 O absorption cycle driven by high-temperature (>275°C) exhaust heat was coupled to a subcritical CO 2 vapor-compression cycle to provide low temperature refrigerant (-40°C) for high-heat flux electronics applications and medium temperature refrigerant (5°C) for space conditioning and other low-heat flux applications. The double-effect absorption/vapor-compression cycle outperformed the corresponding single-effect cycle, providing 74.4% higher cooling capacity for the same waste heat input; however, it required more heat exchange area. The improved performance of the double-effect configuration was much higher at lower heat rejection temperatures. A parametric study on the exhaust and heat rejection temperatures showed that the cycle exhibited high COP s over a wide range of operating conditions, indicating the robustness of the cycle. [ABSTRACT FROM AUTHOR]

Kelp drying plays an important role in kelp processing and storage. However, there are some challenge issues in the kelp drying, such as high labor cost and high power consumption. In order to solve these issues in kelp drying, reduce the labor intensity, save power consumption, and improve the quality of products, a new type of sea-belt drying system combining the natural drying method with the heat pump drying method has been proposed. The new system is based on a task force and cascading design and consists of 5 parts, namely drying room, heat pump room, palletizing device, bridge part and control room. The automatic control system for the kelp drying includes data communication function, dry rod position tracking function, and environmental parameter measurement function. Without the manual labor, such as transport and tumble the fresh kelp, 50 drying rods hanging 100 kg of fresh kelp are automatically lifted to the drying room, a support frame with a length, width and height of 34.5 m × 6 m × 6.5 m for natural drying. The Siemens programmable logic controller (PLC) is used to communicate with the G120 inverter. The Universal Serial Interface (USS) protocol is employed to achieve long-distance acceleration and deceleration of the target position. The Process Field Bus (PROFIBUS) protocol is utilized to communicate with the Sick barcode positioning sensor to ensure accurate positioning of the drying rod. The rod track is used to synchronize the running motor and position the palletizing equipment. The limit switches are used to generate the trigger signal for kelp transmission from the drying room to the heat pump room, that is, the automatic bridge function. The heat pump drying method is to ensure the moisture content of kelp drying achieving high quality after the natural drying procedure. After completing the design of the automatic control system, several kelps are selected as the experimental samples. The test results showed that the walking motor can be adjusted by frequency conversion. The maximum speed is 20 m/min, the minimum speed is 3 m/min, and the maximum efficiency can be achieved before the target position 50 cm to start the deceleration. The distance between the two drying rods in the drying chamber is 37 cm and can also be precisely located. After the natural drying procedure by the sun-drying and air-drying actually, the moisture content of kelp is about 60 %. When the natural drying level (subject to the sunlight-drying degree and air-drying degree) is insufficient, the kelp should be transfer from the drying room to the heat pump room for further drying. The rails of the drying chamber must be connected to the rails of the heat pump chamber. Then the drying rods hanging the kelp automatically are transferred to the support frame in the heat pump room with a length, width and height of 6.5 m × 6 m × 5.6 m. The distance between the two drying rods is 12 cm, which can be precisely located. The moisture content of kelps are dried to about 15.2% eventually, without sediment, impurity rate of 0%, grade I. The whole operation time is about 5.7 h. The results showed that the novel kelp drying system can achieve high quality products with very low energy consumption and labor cost. In addition, it can be used as a reference in the algae processing industry. [ABSTRACT FROM AUTHOR]

From solar, geothermal and waste energy, ultra-low-grade heat of 45–60 °C is large in scale, and is still interesting challenges in converting into useful refrigeration of 7 °C. In this study, a novel cascade refrigeration system was developed to utilize 45–60 °C heat. It is composed of a novel two-stage vapor absorption refrigeration (VAR) subsystem with LiBr/H 2 O working pairs and a conventional vapor compression refrigeration (VCR) subsystem. The VCR subsystem employs potential R1234yf and R1234ze(E) refrigerants. The novel VAR subsystem operates by utilizing ultra-low-grade heat of renewable energy and recycling condensing heat of the VCR subsystem. Based on thermodynamic models of the novel system, its operating mechanism was theoretically investigated and discussed. The results indicate that the novel cascade system can effectively refrigerate by utilizing 45–60 °C ultra-low-grade heat. Its operation is mainly determined by the novel VAR subsystem. There are optimal T m and T g 1 to maximize its performance. T g 2 has a greater impact on the optimal T m and little effects on the optimal T g 1. Furthermore, it implies that an available temperature span could be obviously enlarged from 90 °C down to 45 °C. And, progress of utilizing ultra-low-grade heat of renewable energy could be promoted, beneficially. • A new cascade refrigeration system is proposed to utilize 45–60 °C heat. • Potential environmentally-friendly refrigerants are considered for the new system. • An optimal T m exists to maximize COP net , which is significantly influenced by T g 2. • An optimal T g 1 leads to a maximum COP net , which is little influenced by T g 2. • An available temperature span could be enlarged from 90 °C down to 45 °C. [ABSTRACT FROM AUTHOR]

A method for reducing the characteristic time of action of the pulse produced by explosive magnetic generators is proposed. An experiment was performed whose results confirm that this method can be used in practice. [ABSTRACT FROM AUTHOR]

In order to promote refrigerant substitution by CO 2 for space cooling, and to relieve the requirement of large collector area in the solar-powered ejector refrigeration system, a solar-powered R1234ze/CO 2 cascade refrigeration system was proposed. A theoretical investigation was conducted to estimate the effects of cooling load and solar radiation resources in four cities to denote the influence of the climate on the cascade system. Firstly, the performance of the proposed cascade system was analyzed. Secondly, the effects of solar collector area were illustrated. In comparison with the conventional solar-powered ejector cycle at the given operating conditions, the power consumption of the cascade system is far less when the collector area is lesser. Then the analysis was conducted when the cascade system was applied to different locations. With the increase of the cooling load, the power consumption of the cooling system increases, and the power saving potential increases. Further, the ratio of solar irradiance to cooling load was proposed as criteria for different locations. With the increase of the ratio, collector area needed in the cascade system decreases. And the higher the ratio, the smaller difference of the energy saving potentials between the cascade system and ejection system is. • A solar-powered R1234ze/CO2 cascade cycle was proposed. • The performance of CO2 refrigeration system was improved by applying the ejector and cascade cycle. • The comparison of the cascade cycle with solar ejection cycle was conducted. • The effects of climates on system performance were analyzed. [ABSTRACT FROM AUTHOR]

• R1270 and carbon dioxide was used in the cascade refrigerant system. • A prototype was manufactured and experimental investigation was carried out. • Two semi-hermetic piston compressors were used for high- and low-temperature circuit. • R1270 had good performance on high-temperature circuit and could be used to replace R22 and R134a. Herein, we proposed a c ascade refrigerant system with R1270 and carbon dioxide refrigerants. The natural refrigerant R1270 was adopted in the high-temperature circuit to replace NH 3 and R290. A prototype cascade refrigerant system with two semi-hermetic piston compressors was manufactured, and its performance was investigated experimentally. The results establish R1270 as a good alternative in the high-temperature circuit of the cascade refrigerant system. Moreover, with a constant condensation and evaporation temperature of cascade system, as the R1270 evaporation temperature was decreased (from −7 °C to −19 °C), the coefficient of performance (COP) of the cascade system increased. The isentropic efficiency of R1270 compressor decreased from 78.5% to 74.7% when the R1270 evaporation temperature increased from −19 °C to −7 °C. [ABSTRACT FROM AUTHOR]

The human and animal osmoregulation system is aimed at stabilizing serum osmolality in order to maintain cell volume. It has been shown that the introduction of 5 mL water per 100 g of body weight into the stomach of rats decreases serum osmolality and the concentration of Na and Ca, but not K and Mg. The cascade system of osmotic homeostasis increases secretion of glucagon-like peptide-1 (GLP-1) and oxytocin, and decreases secretion of vasopressin, which reduces the osmotic permeability of collecting duct. After water loading and the injection of 0.015 nM exenatide (GLP-1 mimetic), the time of excretion of 50% of water was halved from 112 ± 4 to 57 ± 5 min (p < 0.01), and after the injection of 0.015 nM oxytocin, it decreased to 83 ± 6 min (p < 0.01). The physiological mechanism of renal effect of the aforementioned hormones which accelerate the recovery of osmotic homeostasis has been found. [ABSTRACT FROM AUTHOR]

[Display omitted] • Drying showed a calcium carbonate production rate of 0.19 mg/h. • In UV–Visible spectrometry, it was possible to differentiate the wavelength between lactate and calcium carbonates at 820 nm. • The biochemical reaction demonstrated a calcium carbonate production rate of 0.40 mg/h. • The limiting step of the process was drying. Cement is the most widely used material in the world. However, a lack of maintenance of concrete structures increases the collapse danger. Against this situation, studies to recover structures are developed using biomineralizing bacteria. The aim of this study was to determine the limiting step in a prototype Cascade System for Biomineralization in Cement (CSBC) comparing crystallization to biochemical reaction by Bacillus cereus. The similar conditions of crystallization and bioreaction indicated that crystallization is the limiting step, with a carbonate production rate of 0.19 mg/h. The results obtained indicated an eco-friendly option to reduce greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

In the context of green and low-carbon production, efficient co-generation systems have received more attention. Many production and life scenarios exhibit the need of constant temperature and low humidity environment. In this paper, an efficient SOFC-based combined cooling, heating, and power (CCHP) system with humidity control has been established for a plant. The innovation is that the cascade absorption refrigeration dehumidification (CARD) subsystem is driven by the waste heat of SOFC to controlling air temperature and humidity effectively. Comprehensive modeling and thermodynamic analysis are carried out. The results reveal that the SOFC stack should be operated in the ohmic loss region. When the recycle ratio is greater than 0.85, the output and efficiency will reduce. The temperature of the liquid desiccant has a large effect on the CARD subsystem. There is a limit to the efficiency gain caused by the increase in the mass flow rate of liquid desiccant. For the system, the energy efficiency reaches 68.3%, the exergy efficiency is 56.3%, and the payback time is less than the life cycle, indicating that the system has better efficiency and economic benefits. This work provides an efficient and cost-saving design solution for practical applications of novel cogeneration systems. • A combined cooling, heating, and power system with humidity control is proposed. • Integration of SOFC, ORC, and a cascade absorption refrigeration dehumidification subsystem. • Energy efficiency reaches 68.3%, the exergy efficiency is 56.3%. • The payback time is less than the life cycle. [ABSTRACT FROM AUTHOR]

The reliability and safety of the cascade system, which is widely applied, have attached attention increasingly. Fault detection and diagnosis can play a significant role in enhancing its reliability and safety. On account of the complexity of the double closed-loop system in operation, the problem of fault diagnosis is relatively complex. For the single fault of the second-order valued system sensors, a real-time fault diagnosis method based on data-driven is proposed in this study. Off-line data is employed to establish static fault detection, location, estimation, and separation models. The static models are calibrated with on-line data to obtain the real-time fault diagnosis models. The real-time calibration, working flow and anti-interference measures of the real-time diagnosis system are given. Experiments results demonstrate the validity and accuracy of the fault diagnosis method, which is suitable for the general cascade system.

In this paper we propose a sliding mode control strategy for cascade systems. Models of first and second order are utilized to design the internal and external control loop respectively. The dead time is considered in the control tunning, which is performed by optimization of the integral square error subject to the existence of sliding mode conditions. A simulation study was performed for a non-linear system representing a Hot-Cold water tank. In addition we study the benefits of our proposal for disturbances and changes in the set-point for the dynamical system. [ABSTRACT FROM AUTHOR]