•Paraffin/metal foam composite PCMs were prepared with vacuum assistance.•The impregnation ratios showed impregnation with vacuum assistance was effective.•The thermal conductivities of the composite ...PCMs were significantly enhanced.•Porous metal foam induced slight shift of the phase change temperatures of PCMs.
The utilization of paraffin in the latent thermal energy storage (LTES) system for solar energy storage is hampered by its low thermal conductivity. Paraffin/nickel foam and paraffin/copper foam composite phase change materials (PCMs) were prepared using a vacuum impregnation method in the present study. The impregnation ratios which reflect the actual mass fraction of pure paraffin impregnated were studied comparatively for the impregnations with and without vacuum assistance. The surface porosity was obtained by employing the image processing approach. The thermal conductivities of the composite PCMs were measured by the transient plane heat source technique (TPS) as well as the steady state method, and the thermal behaviors were analyzed with a differential scanning calorimeter (DSC). It is found that the surface porosity obtained from image analysis was in the range of 90–94%, whereas the bulk porosity predicted by the mass fraction was about 97%. Compared with pure paraffin, the thermal conductivities of the composite PCMs were drastically enhanced, e.g., the thermal conductivity of the paraffin/nickel foam composite was nearly three times larger than that of pure paraffin. The presence of porous metal foam made the phase change temperatures shift slightly, e.g., the deviations of the peak melting temperatures of the paraffin/nickel foam composite and paraffin/copper foam composite with the pore size of 25PPI from those of pure paraffin were 0.55°C and 0.40°C, respectively.
•State-of-the-art review of composite PCMs using high thermal conductivity porous structure is presented.•Fabrication and thermal characterization of composite PCMs are reviewed.•Mathematical ...modeling of the heat transfer mechanisms in composite PCMs is discussed.•Applications of composite PCMs in thermal energy storage and thermal management systems are presented.•Gaps in the current R&D of composite PCMs and future research topics are suggested.
Phase change materials (PCMs) are frequently and widely used in latent thermal energy storage (LTES) system and thermal management (TM) system due to their large latent heats and capabilities of maintaining nearly constant temperature. However, the performances of PCMs in LTES and TM systems are seriously limited by their low thermal conductivities and poor heat transfer performances, which consequently stimulates intensive experimental and theoretical investigations on improving the thermal conductivities and heat transfer performances of PCMs by using different methods. The present paper reviews the recent progresses of the investigations and applications of the composite PCMs with the enhanced performance. The focuses are placed on the composite PCMs fabricated by using the metal foams and carbon materials, which have been proved to be the most promising approaches for thermal conductivity and heat transfer promotion on PCMs. The fabrication processes of the composite PCMs are first introduced in the present paper followed by the thermal characterization. The measurement of the effective thermal conductivities of the composite PCMs is discussed in detail by comparing different measuring methods, and the theoretical models to predict the effective thermal conductivities of the composite PCMs are also presented. The mathematical models describing the phase change heat transfer characteristics of the composite PCMs which are very important for system modeling and design are also addressed and discussed in the present review. Furthermore, the applications of the composite PCMs to LTES and TM systems are introduced and summarized by illustrating the typical examples. It can be understood that the composite PCMs can effectively improve the performances of LTES and TM systems, which therefore calls for the further investigation in this research field. Finally, the future research topics are suggested.
Acupuncture Popularization was a measure taken to construct and improve public health in the early years of New China. Acupuncture Popularization in Guangdong Province was closely combined with the ...interest of the public and the proposal that 'doctors with western background should learn from Chinese medicine'. Some measures, such as extensive mobilization, short-term training and stepwise promotion, were introduced to popularize acupuncture in primary healthcare. This developed Chinese medicine as the process of primary care in New China and improved the 'uniting of Chinese medicine and Western medicine' and the community-level social management. It demonstrated the planning and activities of the New Government in terms of making rational use of Chinese medicine resources and exploring the new public health system adapted to the Chinese context.
•A shell-and-tube latent heat thermal energy storage (LHTES) system using molten salt as the PCM is built.•Thermal energy storage and retrieval characteristics of the LHTES system are experimentally ...and numerically studied.•The performances of eutectic molten salt and nickel foam/salt composite as the PCMs are comparatively studied.•A 3D numerical model is developed to depict the thermal energy storage and retrieval of the LHTES system.
In the present study, a shell-and-tube latent heat thermal energy storage (LHTES) system is built using the eutectic molten salt as the phase change material (PCM) to make an efficient use of solar energy at medium-temperature of around 200.0°C. The nickel foam is embedded in pure PCM (molten salt) to form composite PCM to improve the performance of the LHTES system through enhancing the effective thermal conductivity of the PCM. The performances of the systems using pure molten salt and composite PCM are investigated both experimentally and numerically. The oil is used as the heat transfer fluid (HTF) and the influence of mass flow rate of the HTF on the thermal energy storage and retrieval is investigated in the experiments. The charging and discharging time durations, mean power and energy efficiency are estimated to evaluate the performance of the LHTES system. Meanwhile, a three-dimensional (3D) numerical model is developed based on the enthalpy-porosity model and two-temperature energy equations to investigate the thermal energy storage and retrieval of the LHTES system, and the detailed heat transfer characteristics during the melting/solidification of the PCM are understood. The results indicate that encapsulating molten salt with nickel foam to enhance the effective thermal conductivity of the PCM can improve the performance of the LHTES system. The information provided in the present study will be helpful for the LHTES system design, construction and application using molten salt for solar energy storage.
This paper is the first portion of a two-part study of the heat transfer characteristics of a shell-tube latent thermal energy storage (LTES) system. A three-dimensional computational fluid dynamics ...model based on enthalpy method was developed to investigate the charging characteristics of the LTES system. Pure paraffin and paraffin/expanded graphite (EG) composite PCMs containing 7 wt. % and 10 wt. % EG were used as the phase change materials (PCMs), and water filled in a cylindrical tank was used as the heat transfer fluid (HTF). A variety of numerical investigations were carried out with different inlet temperatures and flow rates of the HTF for heat storage. The temperatures at various locations in the LTES system were experimentally measured and compared with the numerical results. It is shown that the model can accurately predict the thermal behaviors of the LTES system during heat storage. Large temperature difference between the HTF and the initial state of PCM would accelerate the charging process, which could also be significantly improved with the higher flow rate. The performance of the LTES system was affected prominently by the types of PCMs, HTF temperatures and flow rates.
•The charging characteristics of a shell-tube LTES system were investigated.•Paraffin/EG composite PCMs were used to enhance the performance of the system.•The model based on enthalpy method can accurately predict the thermal behavior.•Performance of the system was affected by the HTF temperatures and flow rates.
The thermal conductivity of phase change material (PCM) significantly affects the thermal performance of latent heat thermal energy storage (LHTES) system, which is attractive for energy conservation ...and waste heat utilization. Metal foam can be applied to enhance the low thermal conductivity of pure PCM. In the present study, copper foam and nickel foam with various porosities and pore sizes were impregnated with pure paraffin with vacuum assistance. A steady-state test system which considered the thermal contact resistance (TCR) between the specimen and adjacent surfaces was constructed to measure the effective thermal conductivities of the composite PCMs. The thermal conductivities were also theoretically calculated based on the correlations and models from the literature. The results showed that the thermal conductivities measured with steady-state method showed good agreement with the theoretical predictions, and the thermal conductivities of the composite PCMs were drastically enhanced, e.g., the thermal conductivities of the paraffin/copper foam composite PCMs fabricated by the copper foams with the porosities of 96.95%, 92.31%, 88.89% and pore size of 25 PPI were about thirteen, thirty-one, forty-four times larger than that of pure paraffin, respectively. The ratios of TCR to the total thermal resistances of the composite PCMs with the thickness of about 20.0 mm were in the ranges of 15.0–50.0%.
•Paraffin/metal foam composite PCMs were prepared with vacuum impregnation.•Thermal conductivities of the composite PCMs were measured.•Thermal contact resistance was measured.•Experimental results showed good agreement with theoretical predictions.
Proteins are essential components of organisms and they participate in every process within cells. The key characteristic of proteins that allows their diverse functions is their ability to bind ...other molecules specifically and tightly. With the development of proteomics, exploring high-efficiency detection methods for large-scale proteins is increasingly important. In recent years, rapid development of surface-enhanced Raman scattering (SERS)-based biosensors leads to the SERS realm of applications from chemical analysis to nanostructure characterization and biomedical applications. For proteins, early studies focused on investigating SERS spectra of individual proteins, and the successful design of nanoparticle probes has promoted great progress of SERS-based immunoassays. In this review we outline the development of SERS-based methods for proteins with particular focus on our proposed protein-mediated SERS-active substrates and their applications in label-free and Raman dye-labeled protein detection. graphic removed
Summary
Background
Tong‐Xie‐Yao‐Fang (TXYF) is a Chinese herbal formula for treating chronic diarrhoea accompanied by abdominal pain. The results were inconsistent in previous trials examining its ...effect.
Aim
To study the efficacy of TXYF granules for treating diarrhoea‐predominant irritable bowel syndrome (IBS‐D).
Methods
We performed a double‐blind, placebo‐controlled randomised trial and enrolled 160 participants with IBS‐D. The participants had VAS scores ≥3 cm in IBS‐D global symptoms and ≥2 days in a week with abdominal pain and loose stools (Bristol score 5, 6 or 7). They were randomly assigned to received TXYF or placebo during a treatment period of 4 weeks, and they were followed up for 8 weeks after treatment. The primary outcome was adequate relief of IBS‐D global symptoms for at least 2 of 4 weeks during weeks 1‐4. Secondary outcomes included mean weekly VAS scores of IBS‐D major symptoms, mean weekly stool frequency, mean weekly Bristol score, and adverse events.
Results
155 of 160 patients completed the trial. We found a significantly higher rate of adequate relief of global symptoms in TXFY group during weeks 1 to 4 (57.5% vs 37.5%, χ2 = 5.6391, P = 0.017); logistic regression analysis showed a similar result (OR 2.2, 95% CI 1.2‐4.4, P = 0.016). Most of the secondary outcomes showed superiority of TXYF over placebo in weekly assessment from week 3 to week 7. The adverse event rate was low in both groups (3.8% vs 3.8%, P = 1.000).
Conclusion
During a 4 week trial, TXFY granules were superior to placebo in controlling symptoms of IBS‐D.
Linked ContentThis article is linked to Vitta and Sayuk and Chen et al papers. To view these articles visit https://doi.org/10.1111/apt.14902 and https://doi.org/10.1111/apt.14906.
Objectives To develop a valid statistical method of showing acceptable cardiac output (CO) trending ability when new CO monitors are compared to a reference standard, such as thermodilution, using ...polar coordinates. Design Developing a new statistical analytic method using historic data. Setting University Hospital Anesthesia and Intensive Care Department. Participants Data taken from previously published CO validation studies. Interventions Cartesian data were reanalyzed, being uplifted using Data Thief 3.0 software ( http://datathief.org/ ). Polar plots were constructed from this data. Central zone data (<0.5 L/min or <10% change) were excluded because they introduced statistical noise. Trial polar criteria were set using data from a study that compared 5 CO monitors against thermodilution. Then, these criteria were further validated using data extracted from 15 other studies. Mean (95% confidence intervals) polar angles were used. Measurements and Main Results Trial data suggest ±5° (angle) ±30° (95% confidence interval) as acceptance limits. Concordance rates (ie, >95%-90%) from 5 articles supported trending, and polar data from these studies concurred with the authors' pilot criteria. Favorable comments on trending also were found in 8 of 15 articles in which radial limits were less than ±32°. Good calibration was associated with a mean polar angle of less than ±5°. Conclusions Polar plots can be used to show the trending ability of CO monitors in comparative validation studies. They overcome the deficiencies of concordance analysis, which uses the direction of change as a statistic and ignores the magnitude of change in CO.
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