Summary
Increasing demand of electricity and severer concerns to environment call for green energy sources as well as efficient energy conversion systems. SCO2 power cycles integrated with ...concentrating solar power (CSP) are capable of enhancing the competitiveness of thermal solar electricity. This article makes a comprehensive review of supercritical CO2 power cycles integrated with CSP. A detailed comparison of four typical CSP technologies is conducted, and the cost challenge of currently CSP technologies is pointed out. The thermophysical properties of sCO2 and the corresponding two real gas effects are analyzed elaborately to express the features of sCO2 power cycles. An extensive review of sCO2 layouts relevant for CSP including 12 single layouts and 1 combined layout is implemented logically. Strengths and weaknesses of sCO2 power cycles over traditional steam‐Rankine cycle generally adopted in current CSP plants are concluded, followed by metal material degration summary in CSP relevant temperature sCO2 environment, which shows that the nickel‐based alloy is a proper structural material candidate for sCO2‐CSP integration. Thermodynamic analyses of sCO2 power cycles when integrated with CSP are divided into three level of which design‐point analysis and off‐design modeling are conducted and compared, more researches into the off‐design point analysis, dynamic modeling, especially the transient behavior are suggested. Economic analysis of the integrated system is concluded and presents a considerable levelized cost of electricity reduction of 15.6% to 67.7% compared to that of state of art CSP. Taking the thermodynamic and economic analysis into consideration, target designs of sCO2 power cycles for CSP are summarized in three aspects. Finally, current theoretical and experimental researches of sCO2 power cycles integrated with CSP for market penetration are introduced. The strengths, weaknesses, and potential solutions to the gaps of three potential pathways (molten salt pathway, particle pathway, and gas phase pathway) to realize the integration of sCO2 power cycles in the next CSP generation plants up to 700°C are reviewed. In general, the integration of sCO2 power cycles with CSP technologies exhibits promising expectations for facilitating the competitiveness of thermal solar electricity.
Summary
This article proposes a dynamic analysis framework for a shell and plate particle‐SCO2 moving packed bed heat exchanger (MPBE) with straight SCO2 channel and four fins‐modified SCO2 channels, ...which contains a static model and a dynamic model. 13 cases covering an initial temperature deviation range of +50 ~ −100 K from design‐point case in solids inlet, an initial temperature deviation range of +50 ~ −100 K from design‐point case in SCO2 inlet, and a SCO2 inlet velocity range of 1.5 times to 0.05 times are introduced to measure the dynamic characteristics. Dynamic responses of five MPBE configurations to two types of inputs (step‐change perturbations and linear‐change perturbations) under 13 cases are analyzed. Relaxation times at each case are summarized and compared. A low threshold temperature exists for all five MPBE configurations to avoid oscillations in solids outlet temperature under step‐change perturbations in solids inlet temperature, and a low threshold SCO2 inlet temperature just appears in MPBE with straight SCO2 channels under step‐change perturbations in SCO2 inlet temperature. Improved MPBE configurations show apparent less relaxation time than MPBE with straight SCO2 channel. Among four fins‐modified MPBE configurations, MPBE channels modified with offset rectangular fins on SCO2 side exert the fastest dynamic characteristic in most cases.
Moving packed bed particle/supercritical carbon dioxide (SCO2) heat exchanger (MPBE) is a critical equipment to integrate particle thermal energy storage technology with SCO2 power cycle block in the ...next‐generation concentrated solar power plants. A predictive heat transfer model for designing and evaluation of shell and plate particle/SCO2 moving packed bed heat exchanger is presented, with radiation, pressure drop and SCO2 property variation taking into account. It is found that increasing particle diameter and solids bulk voidage will lower the overall heat transfer coefficient. Change of channel width imposes little effects on the overall heat transfer coefficient, while influences the total heat exchange greatly. MPBE with longer channel length allows smaller overall heat transfer coefficient. Due to approximate linear variation of specific heat and low pressure drop in the nominal boundary operating condition range, ignoring SCO2 Cp variation is valid, and the relative error due to adopting a Cp invariable evaluated at the bulk temperature and constant pressure is less than 1%. Convection resistance generally ranks first in the contribution to thermal resistance, followed by solids‐wall resistance and conduction resistance. Nevertheless, solids‐wall resistance dominates at larger particle diameter (≥550 μm). Radiation is an important contributor to heat transfer behavior, especially at high particle diameter and solids bulk voidage. The relative error caused by neglecting radiation can be up to 23.76%.
The current study aimed to investigate whether red blood cell distribution width (RDW) can predict the prognosis of patients with breast cancer (BC).
We searched four databases, including PubMed, ...Embase, Cochrane Library databases, and CNKI, from inception to Jun 13, 2022. The primary outcome was overall survival (OS), and the secondary outcome was disease-free survival (DFS). A subgroup analysis was conducted based on different treatments. This meta-analysis was performed with RevMan 5.3 (The Cochrane Collaboration, London, United Kingdom).
A total of seven studies including 4,884 BC patients were identified. The high RDW group had a larger tumor size (OR = 2.12, 95% CI = 1.67 to 2.68,
< 0.01), higher proportions of advanced stage tumors (OR = 1.77, 95% CI = 1.38 to 2.27,
< 0.01), more lymph node metastases (OR = 2.00, 95% CI = 1.58 to 2.51,
< 0.01) and lower HER-2 expression (OR = 0.76, 95% CI = 0.61 to 0.95,
= 0.02). For prognosis, after pooling all the data, we found that the high RDW group was associated with worse OS (HR = 2.12, 95% CI = 1.47 to 3.08,
< 0.01) and DFS (HR = 1.77, 95% CI = 1.32 to 2.37,
< 0.01). The subgroup analysis found that RDW had prognostic significance but only for surgery-only patients (HR = 2.41, 95% CI = 1.67 to 3.49,
< 0.01).
High RDW was associated with worse OS and DFS. Therefore, RDW was a simple predictive factor for the prognosis of BC patients.
•Predictive static model to evaluate the thermal-hydraulic performance of a particle-SCO2 MPBE is proposed.•Mechanism to the poor heat transfer behavior in the straight SCO2 channel of a ...particle-SCO2 MPBE is demonstrated.•Four different fin configurations in the SCO2 channel side are presented, analyzed and compared.•Suggestions to the enhanced channel configurations in a particle-SCO2 MPBE are provided.
This article proposes a predictive static model to evaluate the thermal-hydraulic performance of a shell and plate particle-SCO2 moving packed bed heat exchanger, with consideration of pressure drop, radiation and property variations. The results reveal that convection resistance on the SCO2 straight channel side occupies a large part of total thermal resistance in most design and off-design cases. A three-dimensional model inheriting conclusions from the static model is raised, which demonstrates that extremely short entrance region in the x-y plane hinders the overall heat transfer behavior of the SCO2 straight channel. Deservedly, suppressions of the development of thermal layers in the y direction will contribute to improving the thermal-hydraulic performance of the shell and plate particle-SCO2 moving packed bed heat exchanger. Four different fin configurations on SCO2 channel side are presented, analyzed and compared via the static model at the design-point case. Offset rectangular fins configuration behaves the best heat transfer enhancement in total heat transfer rate and overall heat transfer coefficient when compared with the original channel, followed by zigzag fins configuration, offset airfoil fins configuration and s-shaped fins configuration. Zigzag fins-modified channel expresses the worst hydraulic behavior, of which the pressure drop is nearly four times that of original straight channel. The pressure drop of channel with s-shaped fins nearly equals to that of the unmodified channel. Introduction of fins on SCO2 channel side reduces the ratio of convection resistance as a result of apparently increased SCO2 convection coefficients.
Hydrophilic molecularly imprinted polymers（MIPs） were prepared using tetracycline as template,methacrylic acid as monomer and glycidilmethacrylate as pro-hydrophilic co-monomer.Compared with common ...MIPs,the imprinting effect and adsorption amounts of hydrophilic MIPs for tetracycline（TC） were greatly improved in water media.Furthermore,the electrochemical sensor fabricated by modifying hydrophilic MIPs on glassy carbon electrode was developed for the determination of TC in foodstuff samples.
Objective To review recent developments in therapeutic DNA vaccines against tuberculosis.
Data sources The data used in this review were obtained mainly from the studies of therapeutic DNA vaccines ...against tuberculosis reported from 2000 to 2006.
The use of proteins as therapeutics in nanomedicine is an emerging research field and has developed rapidly.However,proteins are always vulnerable to renal excretion or digestion by the proteolytic ...system in vivo,which limits their usage to a large extent.Although biocompatible polymers have been covalently linked to proteins to protect them from recognition by the immune system and prolong their circulation time,the biological activity of them is sometimes decreased.To fill this gap,physical isolation,wrapping,or encapsulation techniques are employed.Up to now,various mature examples were reported,but the whole time scales for guest molecules loading and releasing,especially the initial rapid loading process,were rarely mentioned.Herein,a series of dual-responsive poly（N-isopropylacrylamide-co-methacrylic acid）（P（NIPAM-co-MAA）） microgels were synthesized and employed to investigate the kinetics of in situ complexation and release of lysozyme under external stimuli modulation upon a stopped-flow apparatus,which was suitable for rapid dynamic monitoring.Close inspection of the adsorption kinetics during the early stages（〈 50 s） revealed that the initial microgel collapse occurred within ~1 s,with more rapid transitions being observed when higher lysozyme concentrations were targeted.All the dynamic traces could be well fitted with a double exponential function,suggesting a fast（τ1） and a slow（τ2） relaxation time,respectively.Then,the kinetics of releasing bound lysozyme from microgels was carried on by utilizing the p H-responsive property,and the evaluation of the activity of released lysozyme was synchronously measured in a Micrococcus lysodeikticus（M.lysodeikticus） cell suspension.The corresponding relaxation time（τ） was also calculated by fitting the recorded dynamic traces.We speculate that this work can provide basic dynamics data and theoretical basis for microgels based nanocarriers to be used for protein delivery,controlled release,and possible chemical separation.
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