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Abstract: Three-dimensional (3D) nanostructured Sn2S3 semiconductor films have been prepared on ITO-coated glass substrates by potentiostatic electrodeposition at −0.80V (vs. SCE) from a novel plating bath containing K4P2O3 as a complexing agent and Na2SO3 as a stabilizing agent and by subsequent annealing. Results showed that the annealing drove the as-deposited Sn2S3 films to grow from a granular structure into a nanorod network structure. The nanorods were around 50–100nm in diameter and 1000nm in length. The band gap of the annealed film was 1.65eV and the conductivity was n type. The carrier mobility achieved up to 20.5cm2 V−1 s−1 due to the direct electrical pathways provided by the nanorod network. [ABSTRACT FROM AUTHOR]

Advanced sensation and actuation abilities of various living organisms in nature have inspired researchers to design bioinspired self‐sensing soft actuators. However, the majority of conventional soft actuators primarily possess actuation capabilities while lacking a real‐time sensing signal feedback. Here, a promising strategy is reported to develop highly stretchable and conductive hydrogels for bioinspired self‐sensing soft actuators, which integrate actuation and strain‐sensing functions into a single materials system. The conductive hydrogels are designed and fabricated by in situ copolymerization of amino‐functionalized MXene‐encapsulated liquid metal nanodroplets (LM@A‐MXene) and poly(N‐isopropylacrylamide) hydrogels with controllable activated nanogels as nano‐cross‐linkers. The resulting hydrogel presents a compacted conducting network and highly porous microstructure, giving rise to robust integration of high conductivity, excellent strain sensitivity, broad stretchability, high stability, and fast response speed. Interestingly, the gradient network structure, formed by self‐precipitation of LM@A‐MXene, endows the hydrogel with shape‐programmable actuation, light‐driven remote control, and self‐sensing function. As a proof‐of‐concept application, the soft gripper based on the self‐sensing hydrogel actuators is developed, which can not only grasp, lift, and release objects, but also perceive every movement state by monitoring resistance changes. The proposed self‐sensing soft actuator can offer new insights for developing smart soft robotics and other artificial intelligent devices. [ABSTRACT FROM AUTHOR]

A protein is generally classified into one of the following four structural classes: all α, all β, α+β and α/β. In this paper, based on the weighting to the 20 constituent amino acids, a new method is proposed for predicting the structural class of a protein according to its amino acid composition. The 20 weighting parameters, which reflect the different properties of the 20 constituent amino acids, have been obtained from a training set of proteins through the linear-programming approach. The rate of correct prediction for a training set of proteins by means of the new method was 100%, whereas the highest rate of previous methods was 82.8 %. Furthermore, the results showed that the more numerous training proteins, the more effective the new method. [ABSTRACT FROM AUTHOR]

[Display omitted] • Precursors of salvaged cyanobacteria for Fe-N@C avoided extra additions and saved costs. • Synergistic effect of Fe-N X and graphitic nitrogen efficiently facilitated PMS activation and OFX degradation. • Non-free radicals based on 1O 2 and high-valent iron-oxo species played a major role in OFX degradation. • Fe-N@C-800/PMS system had a strong resistance to influence of inorganic anions. A green, low-cost, high-performance Fe/N co-doped biochar material (Fe-N@C) was synthesized using salvaged cyanobacteria without other extra precursors for peroxymonosulfate (PMS) activation and ofloxacin (OFX) degradation. With the increased pyrolysis temperature, the graphitization degree, the specific surface area and the corresponding groups like OH, COO etc. for Fe-N@C tended to increase, resulting in a greater OFX adsorption. However, the total amount of Fe-N X and graphitic nitrogen groups in the Fe-N@C composites was firstly increased and then decreased, which reached the highest at 800 °C (Fe-N@C-800). All these changes of functional species ascribed to the strong interaction between Fe, N and C led to the highest defect degree of Fe-N@C-800, resulting the highest OFX removal efficiency of 95.0 %. OFX removal experiments indicated the adsorption process promoted the total OFX degradation for different functional groups on Fe-N@C composites separately dominated the process of OFX adsorption and PMS catalysis. Radical quenching and electron paramagnetic resonance (EPR) measurements proved free radical and non-free radical pathways participated in Fe-N@C/PMS system. The non-free radicals based on 1O 2 and high-valent iron-oxo species played a more important role in OFX degradation, leading to the minimal effect of co-existing anions and the high universality for other antibiotic pollutants. Fe-N X was utilized as the main catalytic sites and graphitic nitrogen contributed more to the electron transfer for PMS activation, whose synergistic effect efficiently facilitated OFX degradation. Finally, the possible degradation route of OFX in the Fe-N@C-800/PMS system was proposed. All these results will provide the new insights into the intrinsic mechanism of Fe/N species in carbon-based materials for PMS activation. [ABSTRACT FROM AUTHOR]

Organic cycles play an important role in chemistry, pharmacology and material science for their unique properties. Construction of organic cycles from thioalkynes attracted increasing attention due to the facile access of thioalkynes. 2H‐Azirines were synthesized successfully from thioalkynyl oxime ethers. Cyclobutanes were formed through chiral titanium catalyzed cycloaddition of thioalkynes. Cyclopentenes were afforded by annulation of thioalkynes. Thioalkynes could be also applied to synthesize thiophenes, oxazoles, benzo[b]thiophenes, 2H‐chromenes, 2‐phenylbenzothiazoles, diazacyclobutene, etc. In this review, construction of organic cycles from thioalkynes were highlighted. Firstly, the property and application of organic cyclic compounds were simply introduced. After presenting the general methods to access organic cycles, applications of thioalkynes as synthons to prepare organic cycles were classified and presented in detail. Based on different kinds of organic cycles obtained from thioalkynes, organic reactions for synthesis of three‐, four‐, five‐, six‐membered as well as fused cycles would be summarized and the plausible reaction mechanisms could be presented if available. [ABSTRACT FROM AUTHOR]

Highlights: Design and fabrication of MXene-based soft actuators with angle-independent structural color. The nanostructured MXene can not only facilitate the formation of short-range ordered 3D amorphous photonic crystals, but also help significantly improve structural color saturation. The soft actuators exhibit brilliant angle-independent structural color, ultrafast actuation and recovery speeds in response to vapor. In nature, many living organisms exhibiting unique structural coloration and soft-bodied actuation have inspired scientists to develop advanced structural colored soft actuators toward biomimetic soft robots. However, it is challenging to simultaneously biomimic the angle-independent structural color and shape-morphing capabilities found in the plum-throated cotinga flying bird. Herein, we report biomimetic MXene-based soft actuators with angle-independent structural color that are fabricated through controlled self-assembly of colloidal SiO2 nanoparticles onto highly aligned MXene films followed by vacuum-assisted infiltration of polyvinylidene fluoride into the interstices. The resulting soft actuators are found to exhibit brilliant, angle-independent structural color, as well as ultrafast actuation and recovery speeds (a maximum curvature of 0.52 mm−1 can be achieved within 1.16 s, and a recovery time of ~ 0.24 s) in response to acetone vapor. As proof-of-concept illustrations, structural colored soft actuators are applied to demonstrate a blue gripper-like bird's claw that can capture the target, artificial green tendrils that can twine around tree branches, and an artificial multicolored butterfly that can flutter its wings upon cyclic exposure to acetone vapor. The strategy is expected to offer new insights into the development of biomimetic multifunctional soft actuators for somatosensory soft robotics and next-generation intelligent machines. [ABSTRACT FROM AUTHOR]

Sulfur‐containing alkynes, are important starting materials and intermediates in organic reactions. Some of sulfur‐containing alkynes display interesting bioactivities and are potentially applied as drugs. Various synthetic methodologies towards sulfur‐containing alkynes have been developed, including C(sp)−S coupling, thiolation, S‐alkynylation, trifluoromethylthiolation, etc. In this review, the approaches towards alkynyl sulfides in recent 3 years, as well as to form alkynyl trifluoromethyl sulfides and alkynylthiocyanates were highlighted. Firstly, the property and application of alkynes were introduced. After presenting the superiority of sulfur‐containing alkynes, their synthetic methods were classified and presented in details. According to different kinds of sulfur‐containing alkynes, synthetic methodologies for alkynyl sulfides, alkynyl trifluoromethyl sulfides and alkynylthiocyanates were summarized and the proposed reaction mechanisms were demonstrated if available. [ABSTRACT FROM AUTHOR]

The quality of experimental teaching is closely related to the talent training. Supervision is one of great importance parts in the quality monitoring system of experimental teaching. This paper analyzed the necessity of establishment of experimental teaching supervision, introduced some experience of construction of supervision in Tongji University in recent years from these aspects-organization and implementation of experimental teaching supervision, management and monitoring of experimental teaching process, the experimental teaching evaluation. Showing some true cases, it also described the function of supervision in quality monitoring system of experimental teaching and summarized the effect of supervision, and gave specific views and perspectives of the development and future of the work. [ABSTRACT FROM AUTHOR]

The energy efficiency of traditional PCM wall is low in summer since the PCM storing heat in the daytime will become a secondary heat-source and release the heat into the room again at night. In this paper, a novel pipe-encapsulated PCM wall system for self-activated heat removal is proposed. It integrates PCM, nocturnal radiation cooling and gravity heat-pipe technology, and can realize automatic heat insulation and self-activated removal for buildings. Three simplified models for pipe-encapsulated PCM are developed to predict its thermal characteristics. Model Parameters are determined and identified by using genetic algorithm. The pipe-encapsulated PCM is prepared by RT28 and expanded graphite. An experiment setup is established for model validation. Results shows that the 4R2C PCM model are preferable since the identified parameters are relatively less and the accuracy is also acceptable. Furthermore, a simple application about pipe-encapsulated PCM wall is proposed based on the coupled wall model with 4R2C PCM model. Compared with conventional wall, the internal surface accumulated heat transfer of the pipe-encapsulated PCM wall with night active heat removal in 7 days can be reduced by 74.5% in hot climate. It shows great application potential for energy-saving in buildings. [ABSTRACT FROM AUTHOR]

Indoor air humidity has a significant impact on indoor air quality, building energy consumption, and equipment performance. Excessively low or high humidity is not good for living and working. Hygroscopic materials can be used to moderate the indoor air humidity level. This paper presents a simplified dynamic moisture transfer model of building wall layer of hygroscopic material, and the parameter identification of the simplified model with genetic algorithm by comparing the frequency characteristics of the simplified model with the theoretic frequency characteristics. The proposed simplified model was validated against the published experimental measurements on the system level. The results show that the predicted moisture flux by the simplified model agrees well with the experimental test. The simplified model was also validated on room level by a common exercise in IEA 41 project. The results show that the simplified model has a good agreement with the analytical solution, within ±2.2% in the case CE1A. In the realistic case CE1B, the model prediction matches the results of these detailed models provided in public literature. The proposed simplified dynamic moisture transfer model can be used in building indoor humidity environment and energy consumption simulation with good accuracy and efficiency. • Developing a simplified dynamic moisture transfer model of building wall layer of hygroscopic material. • Model parameters are identified in the frequency domain by the basic material properties. • Validated against the published experiment measurements as well as by a published benchmark exercise. • Much more accurate than the EMPD model and more efficient than the CFD model. • Can be easily integrated into conventional simulation software, such as Simulink or TRNSYS etc. [ABSTRACT FROM AUTHOR]

Abstract Aerogel insulating panels (AIPs) exhibit extensive prospects for application in aerospace, industry and buildings as excellent energy-saving thermal insulators owing to their ultra-low thermal conductivity. This work aims to numerically and experimentally investigate the thermal performance of AIPs in building energy efficiency. The AIPs were prepared and used as an insulation layer in an insulating cell. Three insulating cells with three different insulating materials as the insulation layer were prepared to measure and comparatively analyse their thermal performances. A resistance-capacitance thermal network model to predict the thermal performance of the insulating cells was developed and validated with the experimental data. The thermal indices of cells, i.e. the time lag, decrement factor and daily heat loss, were explored under periodic disturbances of exterior air temperature. Furthermore, the thermal performance of AIPs for exterior walls was predicted by adopting the typical wall structure in the hot summer and warm winter zone of China. The results showed that the AIP wall has decreases of ∼20% and ∼40% in the fluctuation amplitude of the internal temperature and heat flow, respectively, compared with the traditional insulating walls. Highlights • A method to indicate thermal performance of AIP for energy efficiency is proposed. • Three insulating cells with EPS, GF and AIP are prepared and compared. • AIP cell shows twice time lag, 40% less decrement factor and 35% less daily heat loss. • AIP wall has ∼20% and ∼40% decreases in amplitudes of temperature and heat flow. [ABSTRACT FROM AUTHOR]

Roof is a weak part of the building envelope due to the high intensity of solar radiation in summer. Improving thermal performance of roof is crucial to reduce energy consumption. In this study, the thermal performance of a new ventilation roof with shape-stabilized phase change material (SPCM) is investigated. The dynamic heat transfer model for this roof is established by coupling the number of transfer units (NTU) heat exchange model with the resistance-capacity dynamic heat network model and used to analyse the heat transfer. The accuracy of the model is validated by experiment. The indoor air temperature, internal surface temperature of the roof, and cumulative cooling load in summer are simulated and analysed in Wuhan. The results show that PCM and night ventilation have great energy saving potential. When the 30 mm PCM is applied, the peak indoor air temperature and peak internal surface temperature decreased by 2.9 °C and 5.5 °C, respectively, and the cumulative cooling load of the building decreases by 19.2%. When night ventilation is applied (v = 3 m/s), the average latent heat utilization rate of the PCM layer increases, and the cumulative cooling load decreases by 22.9% and 37.5% compared with the PCM roof and the reference roof, respectively. [ABSTRACT FROM AUTHOR]

• A comprehensive heat transfer model of the air permeable wall was developed. • Thermal insulation mainly lies in the exfiltration process across porous layer. • Sensitivity analysis was performed to identify the impact of design parameters. • The thickness of air permeable porous layer between 30 and 50 mm was recommended. The exhaust air insulation (EAI) wall is a novel type of air permeable wall that is characterized by a permeable porous layer. Such a wall design provides a solution to combine the building envelope with exhaust air heat recovery, and allows the exhaust air from a conditioned room to permeate through. The exfiltration process of the exhaust air across the porous layer can partly reduce the inward conductive heat flux through the wall. This makes the temperature at the innermost surface of the EAI wall close to the temperature of the indoor air, and leads to the reduction of cooling and heating loads through the wall. In this study, a comprehensive heat transfer model was developed to analyze the steady state thermal characteristics of the EAI wall. Forty different experiments were performed to verify the proposed model. A quantitative analysis was conducted on the differences when using the unsteady state model and proposed steady state model for the EAI wall with an outdoor thermal disturbance. A sensitivity analysis was carried out to investigate the impact of the design parameters on the thermal characteristics of the EAI wall. The results showed that using a porous material with relatively low thermal conductivity such as phenolic foam is beneficial to improve the heat recovery performance and thermal insulation of the EAI wall. The thermal insulation of the EAI wall is mainly due to the exfiltration process of exhaust air across the porous material. Considering the impact of the design parameters on the thermal characteristic, total thickness and pressure drop, a thickness of 30–50 mm is recommended for the porous material. At an exfiltration velocity of 0.003 m/s, the U-value of the EAI wall was lower than 0.1 W/(m2 K) for a porous material thickness of 30–50 mm. These results demonstrate that the EAI wall is applicable to both energy-efficient retrofitting of existing buildings and new buildings, and can potentially contribute to reduce the cooling and heating loads through the wall by the utilization of low-grade thermal energy in exhaust air. [ABSTRACT FROM AUTHOR]

Downregulation of microRNA-34a (miR-34a) has frequently been observed in esophageal squamous cell carcinoma (ESCC). However, the underlying role and molecular mechanism of miR-34a in ESCC remains largely unknown. In the current study, it was demonstrated that miR-34a was downregulated and forkhead box M1 (FOXM1), a target gene of miR-34a, was upregulated in ESCC tumor tissues. Overexpression of miR-34a decreased FOXM1 mRNA and protein expression in the ESCC cell lines tested (TE-1 and TE-8). Inhibition of miR-34a increased FOXM1 mRNA and protein levels in human esophageal epithelial cells (HEEC). In addition, miR-34a mimics reduced the relative luciferase activity of ESCC cells transfected with FOXM1 3′UTR-WT, but not FOXM1 3′UTR-Mut. The CCK8 assay and scratch wound healing assay showed that overexpression of miR-34a induced inhibition of cell proliferation and cell migration. Additionally, transfection with miR-34a mimics reduced the expression of key genes involved in cell migration (MMP2 and MMP9) in ESCC cells. Thus, the present data demonstrated that miR-34a suppressed ESCC progression by directly targeting FOXM1. [ABSTRACT FROM AUTHOR]

Ground heat exchanger takes the soil underground as heat source or sink to supply cooling or heating. It has been widely used in building heating and cooling systems due to high efficiency and environmental friendliness. This paper reviews the latest research on ground heat exchangers from several new perspectives and demonstrates their potentials in achieving zero energy buildings. Firstly, ground heat exchangers are classified into water-based and air-based ones based on the heat transfer medium. They can be used in a passive or active approach. Associated research and projects for each approach are introduced and analysed. Then the integration of ground heat exchangers with various cooling and heating technologies and related studies are reviewed. These technologies include solar thermal collectors, cooling towers, nocturnal radiative cooling technology, solar chimney, etc. Finally, a technical route for ground heat exchangers to help realize zero energy buildings is presented, which provides a promising solution to improve energy efficiency of buildings. [ABSTRACT FROM AUTHOR]

A hollow block ventilation wall (HBVW) is an innovative construction where the block cavity of the wall is used as a ventilation duct. Low-grade energy can be used to remove heat stored in the structure in summer and warm the structure in winter. Therefore, the cooling and heating loads of buildings can be significantly reduced. Therefore, an experimental study was conducted to investigate the thermal performance of HBVW under different airflow temperatures and rates. The temperatures and heat flux of HBVW surfaces and the airflow temperatures in cavity were tested on a typical summer day. The results show that the air velocity in the cavity has a great influence on the thermal performance. Compared with a non-ventilation wall, the thermal resistance increases from 0.637 m 2 K/W to 1.61, 3.06, 3.86, and 4.12 m 2 K/W when the air velocity is 0.3, 0.9, 1.5, and 1.9 m/s, respectively, and the heat flux transferred through the inner surface can be decreased by 40.5%, 73.3%, 79.4%, and 82.6%. The average temperature of the inner surface can be respectively decreased by 1.8, 2.8, 3.0, and 3.1 °C. The airflow temperature has little effect on the equivalent heat resistance, but it does greatly affect the inner surface temperature. [ABSTRACT FROM AUTHOR]

Sophisticated sensing and actuation capabilities of many living organisms in nature have inspired scientists to develop biomimetic somatosensory soft robots. Herein, the design and fabrication of homogeneous and highly conductive hydrogels for bioinspired somatosensory soft actuators are reported. The conductive hydrogels are synthesized by in situ copolymerization of conductive surface‐functionalized MXene/Poly(3,4‐ethylenedioxythiophene)/poly(styrenesulfonate) ink with thermoresponsive poly(N‐isopropylacrylamide) hydrogels. The resulting hydrogels are found to exhibit high conductivity (11.76 S m−1), strain sensitivity (GF of 9.93), broad working strain range (≈560% strain), and high stability after over 300 loading–unloading cycles at 100% strain. Importantly, shape‐programmable somatosensory hydrogel actuators with rapid response, light‐driven remote control, and self‐sensing capability are developed by chemically integrating the conductive hydrogels with a structurally colored polymer. As the proof‐of‐concept illustration, structurally colored hydrogel actuators are applied for devising light‐driven programmable shape‐morphing of an artificial octopus, an artificial fish, and a soft gripper that can simultaneously monitor their own motions via real‐time resistance variation. This work is expected to offer new insights into the design of advanced somatosensory materials with self‐sensing and actuation capabilities, and pave an avenue for the development of soft‐matter‐based self‐regulatory intelligence via built‐in feedback control that is of paramount significance for intelligent soft robotics and automated machines. [ABSTRACT FROM AUTHOR]

The aim of the present study as to analyse the associations between circulating tumour cells (CTCs) and the clinical parameters of nasopharyngeal carcinoma (NPC). Peripheral blood (7.5 ml) from 68 first-diagnosed NPC patients was collected to detect and identify CTCs by cluster of differentiation (CD)45 immunomagnetic separation. Immunofluorescent staining of cytokeratin-18, CD45 and DAPI, and fluorescence in situ hybridization were combined with the centromere of chromosome 8 (CEP8) probe method to analyse the associations between CTCs and clinical parameters. One-year follow-up of the NPC patients who received standardized treatment was also performed to analyse the associations between CTCs, tumour development and the treatment effect. The detection rate of CTCs in the 68 NPC patients was 98.5% and the positive rate of CTCs was 60.3%. The positive rates of CTCs in the I-III and IV stage patients were 51.1 and 78.3%, respectively; the rate was 90.0% in the M1 stage and 55.2% in the M0 stage. The differences were statistically significant (P<0.05). The mean CTC counts were 3.86±2.36 and 5.70±2.91 in the M0 and M1 stages, respectively, which was significantly different (P=0.031). The 12-month follow-up record suggested tumour progression for 17 patients, and the one-year progress free survival rate was 74.6%. Among the CTC-positive stages III-IV patients, the disease progression rate of the patients who had received treatment including chemotherapy/intensity-modulated radiation therapy (IMRT) was 83.3%, which was higher than that of the patients who received treatment including [ABSTRACT FROM AUTHOR]

Net zero energy building (NZEB) is widely considered an effective solution to the increasing energy and environmental problems. Focusing on performance optimizations at single-building-level, conventional control strategies have not considered collaborations among NZEBs (such as renewable energy sharing) and thus optimal results may not be able to be achieved at a higher level, i.e. building-group-level. Few studies have evaluated the building-group-level performance of NZEBs using non-collaborative controls and researchers are still unclear about the performance improvement potentials if collaborative controls are implemented. Considering economic cost, load matching and grid interaction, this study aims to evaluate the performance of a group of NZEBs in which conventional controls are used. Meanwhile, associated performance improvement potentials are analyzed at building-group-level. The study results show that significant performance improvement potentials exist if NZEB collaborations are enabled. The study results also analyze the benefits of the NZEB collaborations in the three different aspects. To improve NZEB performance at building-group-level, new collaborative controls need to be developed to replace the conventional ones. [ABSTRACT FROM AUTHOR]

This study investigated the backwater effect of the eight bridges along the Huaihe River in China using physical model experiments. The experimental data obtained were used to derive equations to parameterise the backwater effect of a single bridge. The cumulative effect of two bridges was then analysed, using the backwater effect of a single bridge as a reference. It was found that, in order to eliminate the cumulative effect, the minimum distance between two bridges should be no less than 215 times the bridge pier width. [ABSTRACT FROM AUTHOR]

The first example of paired electrolysis-enabled cyanation of diaryl diselenides, with KSCN as the green cyanating agent, has been developed. A broad range of aryl selenocyanates can be efficiently synthesized under chemical-oxidant- and additive-free, energy-saving and mild conditions. [ABSTRACT FROM AUTHOR]

Various indole-containing compounds have shown impressive pharmaceutical activities against a variety of diseases. However, the functionalization of indoles usually relies on systems that use organic solvents, which do not meet the criteria for green and sustainable chemical development. To address this issue, regiospecific sulfenylation, selenylation, and telluration of indoles were developed using H2 O as solvent. The highly efficient chalcogenylation of indoles was achieved utilizing CsOH as a promoter, thus avoiding the use of expensive transition-metal catalysts. This newly developed protocol is characterized by its outstanding features including simple operation, mild conditions, wide substrate scope, excellent functional group tolerance, and recyclability, leading to the convenient synthesis of 3-chalcogenyl-indoles. [ABSTRACT FROM AUTHOR]

Cationic mononuclear zirconocene and titanocene perfluorooctanesulfonate complexes are successfully applied in various transformation reactions of carbonyl compounds. [ABSTRACT FROM AUTHOR]

The hollow block ventilated wall is a new kind of ventilated wall, the exhaust air of HVAC system is used as the supply air to flow through the cavity of this wall in this paper. The heat or cool storage in the wall is reduced by using the heat recovery technology; the temperature of internal surface is lowered in summer and increased in winter, and the human thermal comfort is enhanced. A semi-dynamic heat transfer model of the ventilated wall is presented for thermal performance prediction. The dynamic optimized resistance-capacitance (ORC) model and the number of transfer units (NTU) model are joined together to develop the semi-dynamic heat transfer model of this ventilated wall. The experimental study is carried out for validating the semi-dynamic heat transfer model. The maximum relative error is 4.3% for mean internal and external surface temperatures, and it is 2.6% for the outlet air temperature of the cavity. The heat transfer model established for hollow block ventilated wall is fairly reasonable and possesses high accuracy. This model can be used to predict the surface temperature of the hollow block ventilated wall and the heat flux removed by the airflow in the cavity for performance evaluation. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on a bilinear temperature control of a ground source heat pump (GSHP) integrated variable air volume (VAV) air-conditioning system, which may experience significant variations in the supply air temperature due to the frequent on/off switch of the ground source heat pump and the low thermal capacity at the air side. The bilinear control was realized in a building automation system (BAS) and applied to a test rig. The experimental results show that with an online estimation of the cooling load the bilinear control was able to maintain the space temperature at its set-point well and the control performance was superior to that of a conventional PI control. Therefore, the bilinear control has the potential to be used in GSHP integrated air-conditioning systems to improve the robustness and accuracy of the space temperature control. [ABSTRACT FROM AUTHOR]

A convenient and efficient method for the synthesis of O,O -dialkyl- Se -aryl phosphoroselenoates is described via a one pot reaction of diaryl diselenide and O,O -dialkylphosphonate catalyzed by KOH assisted by a co-catalyst of calix[4]arene 3 . The calix[4]arene 3 can be recycled for five times with good yields of the desired products for the reaction. This protocol provide a simple and efficient method for the synthesis of O,O -dialkyl- Se -aryl phosphoroselenoates, avoiding the use of toxic reagents and expensive catalysts. [ABSTRACT FROM AUTHOR]

This paper studies the optimization of a small-scale central air-conditioning system, in which the cooling is provided by a ground source heat pump (GSHP) equipped with an on/off capacity control. The optimization strategy aims to optimize the overall system energy consumption and simultaneously guarantee the robustness of the space air temperature control without violating the allowed GSHP maximum start-ups number per hour specified by customers. The set-point of the chilled water return temperature and the width of the water temperature control band are used as the decision variables for the optimization. The performance of the proposed strategy was tested on a simulation platform. Results show that the optimization strategy can save the energy consumption by 9.59% in a typical spring day and 2.97% in a typical summer day. Meanwhile it is able to enhance the space air temperature control robustness when compared with a basic control strategy without optimization. [ABSTRACT FROM AUTHOR]

Hot brine injection is one of the most effective dissociation methods of natural gas hydrate, and the movement of thermal front is a key parameter to evaluate the production performance by hot brine injection. Based on the principle of energy conservation, a mathematical model for thermal front movement of gas hydrate dissociation by hot brine injection is developed, which is derived through Laplace transform. In addition, an experimental study on the movement of thermal front is conducted with a self-designed 1D natural gas hydrate dissociation apparatus. The thermal front movement of the experiment is compared with that calculated from the mathematical model established in this paper as well as other two models proposed by Selim and Sloan (1990) and Tang et al. (2006), respectively. It turns out that what fits better with the experimental data is the energy conservation model, which includes the effect of heat used to warm the dissociated reservoir, heat absorption by hydrate dissociation and heat loss to the cap and base sediments. Therefore, this energy conservation model is an effective method to analyze the thermal front of gas hydrate dissociation by hot brine injection. [ABSTRACT FROM PUBLISHER]

This paper presents a method which combines the bilinear control technique with a set-point reset technique to control the space temperature when its cooling is provided by a GSHP equipped with an on/off capacity control, aiming to (i) improve the robustness of the space temperature control by taking account of load uncertainty; and (ii) to reduce the frequency of the GSHP on/off cycling by using the indoor space temperature set-point reset. When the GSHP is on, a smaller space temperature set point is used; while the GSHP is off, a larger set point is used. The proposed control was tested on a simulation platform, which consists of a ground source heat exchanger, a GSHP, an air-handling unit (AHU) and a middle-sized room. The test results show that the proposed control method is able to achieve a good control performance and has the potential to be applied to a real GSHP integrated air conditioning system to improve the robustness of space temperature control and simultaneously reduce the on/off frequency of the GSHP. [ABSTRACT FROM AUTHOR]

Developing hydrogel actuators with excellent driving performance and extended lifespan remains challenging. Ti3C2Tx MXene, as a two-dimensional nanomaterial with a unique layered structure, has attracted widespread attention in flexible hydrogel actuators for its excellent optical absorption properties and tunable surface functionality. However, MXene faces difficulties in dispersion and is prone to oxidation, which significantly hinders the development and use of MXene-based hydrogel actuators. In this study, we fabricated a near-infrared light-driven hydrogel actuator with rapid photo responsiveness and antioxidative properties by incorporating modified MXene with antioxidant characteristics and the pore-forming agent polyvinyl alcohol into the poly(N-isopropylacrylamide) (PNIPAM) hydrogel system. We functionalized MXene nanosheets with (3-aminopropyl)triethoxysilane (APTES), effectively enhancing antioxidative properties, preventing structural degradation caused by spontaneous oxidation, and improving surface properties. This enhanced the dispersion stability of MXene in the system and extended its lifespan from 7 days to over two weeks. The hydrophilic polyvinyl alcohol chains served as drainage channels during hydrogel contraction, imparting the hydrogel with rapid driving capabilities (127.1° s−1). Additionally, leveraging the fast response characteristics, we designed an octopus-inspired light-driven soft swimmer and gripper. This work provides novel insights into the application of intelligent responsive hydrogels in biomimetic and practical scenarios.Graphical abstract: Developing hydrogel actuators with excellent driving performance and extended lifespan remains challenging. Ti3C2Tx MXene, as a two-dimensional nanomaterial with a unique layered structure, has attracted widespread attention in flexible hydrogel actuators for its excellent optical absorption properties and tunable surface functionality. However, MXene faces difficulties in dispersion and is prone to oxidation, which significantly hinders the development and use of MXene-based hydrogel actuators. In this study, we fabricated a near-infrared light-driven hydrogel actuator with rapid photo responsiveness and antioxidative properties by incorporating modified MXene with antioxidant characteristics and the pore-forming agent polyvinyl alcohol into the poly(N-isopropylacrylamide) (PNIPAM) hydrogel system. We functionalized MXene nanosheets with (3-aminopropyl)triethoxysilane (APTES), effectively enhancing antioxidative properties, preventing structural degradation caused by spontaneous oxidation, and improving surface properties. This enhanced the dispersion stability of MXene in the system and extended its lifespan from 7 days to over two weeks. The hydrophilic polyvinyl alcohol chains served as drainage channels during hydrogel contraction, imparting the hydrogel with rapid driving capabilities (127.1° s−1). Additionally, leveraging the fast response characteristics, we designed an octopus-inspired light-driven soft swimmer and gripper. This work provides novel insights into the application of intelligent responsive hydrogels in biomimetic and practical scenarios. [ABSTRACT FROM AUTHOR]

• Energy performance of HVACs in super high-rise buildings were field-tested and analyzed. • The representative issues leading to large energy consumption of HVACs were summarized. • Commissioning of VAV system and multistage chilled water systems were conducted. • The setting values of HVACs should be adjusted in time according to practical cooling demand. The HVACs in super high-rise buildings commonly consists of variable air volume (VAV) systems, multistage chilled and cooling water systems, primary-secondary chilled water system in chiller plant, and the chillers combination is much more complex, leading to the significantly higher energy consumption than that of normal buildings. This paper contains field tests and comparative studies on the operation performance of HVACs in two super high-rise buildings and summarized representative issues accounting for the high energy consumption. Field test results showed that the annual energy efficiency of the whole HVAC system, before being commissioned, was only 1.79 and 2.15 in two projects. The HVACs, typically VAV systems, chilled and cooling water systems, all suffered from over-supplying and energy wasting. Besides, the chillers commonly operated with a low partial load ratio (PLR), whose energy performance was much lower than expected. Aiming to dig out the typical issues, analyses were carried out from external, internal factors, and their interconnection. Furthermore, optimization methods were put forward with corrected vital indexes. Results showed that proper control strategies should maintain the VAV system, multistage chilled and cooling water system operating with significant distribution temperature differences, tiny distribution pressure drops, and high energy efficiency, thus achieving energy saving and ensuring space cooling effects. Besides, the control strategies, especially the number control of chillers, were influential during the whole cooling season to ensure the chillers operate with optimal PLR and thus achieve better energy performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • MOFs act as dual-functional adsorbents and electrocatalysts for the removal of PPCPs. • Real active sites of MOFs are pinpointed using in-situ electrochemical methods. • Fe-MOFs exhibit high efficacy and stability in practical wastewater treatment. Pharmaceuticals and personal care products (PPCPs) pose a significant wastewater pollution concern. While electrochemical oxidation is promising, it struggles with slow mass transfer. To address this, we propose a novel strategy utilizing bifunctional metal–organic frameworks (MOFs) that couple an adsorbent with an electrocatalyst. The real active sites within iron-based MOFs responsible for the adsorption of PPCPs are MIL-101(Fe) molecules, while the in-situ formed active sites, α -FeOOH, accelerate the charge transfer under bias, contributing to the electrooxidation of PPCPs. The rapid destruction of adsorbed organics on the dual-functional electrode surface enables to release adsorption sites. This, in turn, paves the way for fast and efficient re-adsorption of PPCPs molecules, consequently promoting mass transfer. Iron-based MOFs exhibit excellent adsorption capacity (∼60 mg g−1 for sulfosalicylic acid, ∼15 mg g−1 for acetaminophen) and electrooxidation ability (94 % removal in 2 h, 31.2 kWh kg−1 COD) with good stability in realistic pharmaceutical wastewater treatment. This study offers a novel strategy for removing PPCPs using molecular electrocatalysts and provides new insights for designing and constructing MOFs for refractory wastewater treatment. [ABSTRACT FROM AUTHOR]

Effective evaluation on the thermal performance of envelope plays an important role towards the reduction of energy consumption for space cooling and heating. In order to calculate the energy consumption for cooling and heating and assess the whole energy efficiency of envelop designs, a new evaluation index on energy and thermal performance for office building envelop (EETPO) is put forward. Three cities of Shenyang, Wuhan and Guangzhou in China are selected for EETPO analysis, which represent the cold zone, hot summer cold winter zone and hot summer warm winter zone, respectively. The regression equations between EETPO and energy use for cooling/heating are studied in three cities, illustrations indicate that the regression lines fit extremely well and the algorithm is accurate and simple. According to the compulsory indices stipulated by standard (GB50189-2005), the maximum allowable values of EETPO are determined in three cities, the maximum EETPO c in cooling period is 1.750 W/m 3 K in Wuhan and 1.733 W/m 3 K in Guangzhou, the maximum EETPO h in heating period is 0.200 W/m 3 K in Shenyang and 0.414 W/m 3 K in Wuhan. This index and energy use calculation method can help designers to evaluate the whole energy and thermal performance of the proposed envelopes and analyze energy saving effects for different energy conservation measures. [ABSTRACT FROM AUTHOR]

With the growth of high performance electronics, more consideration should be given to the safety issues associated with thermal runaway. Previous strategies have often been limited by shutdown efficiency and shutdown temperature. Here, we present a MXene supercapacitor loaded with a smart thermally responsive electrolyte to cope with thermal runaway at high temperatures. At room temperature, the ions in the electrolyte containing the poly (N‐isopropylacrylamide‐co‐glycidyl methacrylate) (PNGM) can migrate freely and the devices can operate normally. The smart electrolyte system forms a hydrophobic network that effectively inhibits ion migration to achieve thermal shutdown at high temperatures. The electrolyte system exhibits different electrochemical properties during heating up, reaching nearly 90 % capacity suppression at 85 °C. The proposed smart electrolyte system provides a promising solution to the thermal safety suitable for current electronic devices by achieving a proactive protection strategy. [ABSTRACT FROM AUTHOR]

Dewatering is important for activated sludge disposal. The dewaterability of activated sludge was first deteriorated and then ameliorated when the temperature was raised from 100 to 200 °C with a threshold temperature of 130 °C under hydrothermal treatment. Calcium chloride assisted hydrothermal treatment to improve the dewaterability of activated sludge, and eliminated the threshold temperature at as less as 20 mg/g dry solid (DS). An increase in temperature and dosage of CaCl2 till 60 mg/g DS allowed a continuous improvement of dewaterability. It is found that the charge neutralization resulted from biopolymers solubilization dominated the dewaterability evolution below 160 °C, while the decomposition of water-binding components played a more important role at higher temperatures. The variation of molecular weight of soluble protein and polysaccharides implies that CaCl2 interacted with the component of sludge and altered the constituent during the hydrothermal treatment. The integration of soluble biopolymers into the floc matrix by CaCl2 contributed to the compacted floc structure and thus improved the dewaterability. This work presents an insight into the floc variation in both the composition and structure associated with the dewaterability and offers a new understanding to the role of temperature and CaCl2 in hydrothermal treatment on activated sludge dewatering. [ABSTRACT FROM AUTHOR]

The two air-stable μ2-hydroxy-bridged binuclear hafnocene perfluorobutanesulfonate and perfluorobenzenesulfonate complexes were successfully synthesized. The high catalytic activity and recyclability of these complexes were exemplified for various carbon-carbon bond formation reactions. Compared with our previously reported hafnocene perfluorooctanesulfonate, these complexes show stronger Lewis acidity and better catalytic activity, and should find broad applications in organic synthesis. [ABSTRACT FROM AUTHOR]

Radiant cooling in buildings, as an energy-saving and comfort cooling method, is very promising in creating a green and healthy indoor thermal environment in buildings. However, radiant panels are prone to dew condensation and have low cooling capacity; thus, their application in hot and humid regions is limited. Covering the surface of the radiant cooling panel with a high transmittance low conductivity material (HTLCM), and, separating the air contact surface and the radiating surface, to form a new decoupled radiant cooling technology is an effective way to address the deficient radiant cooling capacity and easy condensation. Radiation heat exchange occurs between the radiant cooling surface and the indoor heat source surface through the HTLCM, while the indoor humid air undergoes convective heat exchange with the higher temperature HTLCM surface. The optical, and thermal properties of the material determine the cooling capacity and condensation resistance (thermal performance) of the radiant cooling air conditioning. This review provides a summary of the research advances in HTLCM-assisted radiant cooling air conditioning (RCAC) in recent years. First, the classification and optical and thermal properties of the currently used HTLCMs for radiant cooling are presented. Second, the heat transfer mechanism of RCAC with HTLCM is introduced. Finally, the research advances in the application of HTLCM-assisted radiant cooling are summarized, and the challenges and future development in this field are provided. The practical engineering application of HTLCM-assisted radiant cooling units in hot and humid regions is highlighted. • Material, mechanism, application of HTLCM-assisted radiant cooling are discussed. • Structural design, thermal performance, and cooling effective of RCAC are presented. • HTLCM improves condensation resistance, cooling capacity, temperature range of RCAC. • An updated review and discussion of HTLCM-assisted RCAC is provided. [ABSTRACT FROM AUTHOR]

Renewable energy is becoming increasingly popular in the development of low-carbon societies. Radiative sky cooling (RSC) technology utilizes long waves in the atmospheric window to radiate heat into outer space; it promises a good cooling effect and wide applicability. This paper reviews RSC technology in terms of its background, materials, heat transfer and influences, and applications in buildings. High-performance radiative cooling materials have been proposed to realize RSC during both the day and night. Using these materials, sky radiative coolers and cooling systems have been fabricated for different scenarios. Radiative and non-radiative heat transfer and cooling performances can be calculated or measured using the radiation law. The correlations between the sky effective radiative temperature and effective emissivity are summarized. Environment conditions affect the RSC performance, and the influences are systematically analyzed. Owing to its advantages of cleanliness, accessibility, and extensive resources, RSC technology can be applied to building envelopes and heating, ventilation, and air conditioning systems, to develop low-carbon and zero-energy buildings. Passive and active applications are also discussed. Finally, challenges of applying RSC technology to building systems are briefly discussed. This review should help promote the practice and implementation of RSC technology. • Spectrally selective radiative cooling materials and cooler forms are reviewed. • Heat-transfer parameters, performances and influences of RSC are summarized and analyzed. • Applications of RSC in building envelopes and HVAC systems are presented. • Challenges on RSC applied to buildings are discussed. [ABSTRACT FROM AUTHOR]

• DFT calculation fully supported the results predicted by CD-MUSIC model. • As(V) and Sb(V) exhibited a stronger affinity for bidentate coordination. • P(V) exhibited a stronger affinity for monodentate coordination. • The adsorption competitiveness of As(V) and P(V) was generally stronger than Sb(V). • Ion existing form and coordination structure affinity decided adsorption behavior. Despite the geochemical prominence of As(V), Sb(V), and P(V) coexisting in an extensive array of iron-oxide environments, the comprehension of their mobility and destiny is constrained due to the differences in the surface properties and exposed crystal facets of iron oxides. Herein, goethite primarily exposing the {1 1 0} facet, was employed as the model iron mineral to investigate the competitive adsorption behavior of As(V), Sb(V), and P(V) via batch experiments leveraging EXAFS, CD-MUSIC model, and DFT calculations. Results showed that observed co-adsorption behaviors were attributed to the comprehensive action of goethite surface chemistry, ion existing forms and different coordination structures stability at the molecular scale. CD-MUSIC model indicated As(V) and P(V) competed for surface sites through a combination of bidentate and monodentate coordination, whereas Sb(V) was primarily adsorbed via bidentate coordination, which led to the surpassed competitiveness of As(V) and P(V) on {1 1 0} facet compared to that of Sb(V). The affinity of various coordination structures on {1 1 0} facets based on DFT was found to be consistent with the trends predicted by the CD-MUSIC model. Specifically, As(V) and Sb(V) exhibited a greater affinity for bidentate coordination, while P(V) tended to form monodentate coordination complexes. However, the existing forms of As(V), Sb(V), and P(V) under different pH, especially for protonated species, accelerated the more weakened competitive combination ability of Sb(V) than As(V) and P(V) with increasing pH. Furthermore, charge density difference and Bader analysis have confirmed the contribution of electron transfer from the surface Fe to O towards forming Fe O bonds. This work provided a novel investigation way and facilitated a more profound understanding of the geochemical cycle of toxic metals. [ABSTRACT FROM AUTHOR]

Abstract: Highly graphitic carbon black (GCB) was synthesized by heat-treating commercial carbon black (CB, Vulcan XC-72) at 2800°C. The resulting GCB with a high degree of graphitization was analyzed by X-ray diffraction patterns (XRD), Raman spectroscopy and high-resolution transmission electron microscopy (HR-TEM) and was then used as the support material for synthesizing a platinum–GCB (Pt/GCB) hybrid catalyst. This catalyst was obtained through a simple chemical reduction using ethylene glycol as the reducing agent, which is amenable to large-scale production. The results show that the Pt nanoparticles are highly dispersed on the GCB with an average diameter of 3.6nm and a narrow particle size distribution. The electrochemical results obtained using cyclic voltammetry (CV), linear sweep voltammetry (LSV) utilizing a rotating disk electrode (RDE) and electrochemical impedance spectroscopy (EIS) show that the Pt/GCB electrocatalyst exhibits higher conductivity, stability, and electrocatalytic activity for the oxygen reduction reaction. The ORR proceeds through a four-electron process and when compared with Pt nanoparticles supported on Vulcan XC-72 (Pt/Vulcan XC-72) prepared under the same conditions, the Pt/GCB exhibits a significant enhancement for the ORR reaction. [Copyright &y& Elsevier]

Background: To evaluate the technology of transesophageal echocardiographic guidance of percardiac closure in patients with low weight. Methods: Forty-two patients with intracardiac defects, aged from two months to five years (median, 18.4 months) and weighted from 4 to 10 kg (median, 8.9 kg), underwent attempted percardiac device closure under transesophageal echocardiographic guidance. Results: Thirty-nine (93%) patients successfully underwent occlusion, whereas three patients (7.1%) were converted to conventional open-heart surgery. There was no mortality. They were followed up from 3 months to 15 months (median, 9.4 months). First degree atrioventricular block was detected in one patient at the time of discharge. The most common electrocardiogram change was bundle-branch block, which developed in three (7.7%) patients during follow-up. New mild mitral valve regurgitation (MR) was detected in three patients after operation and disappeared in one but remained in two others. Pericardial perfusion and recurrent intubation developed in one patient, respectively. The incidence of late complications is 5.1% (2/39) including low cardiac output syndrome and residual shunt in one patient, and moderate pericardial perfusion in one patient, respectively. No complication such as device dislocation, thrombosis, and obstruction of left or right ventricular outflow tract was found during the follow-up. Conclusions: This initial success indicates that transesophageal echocardiographic guidance of percardiac device closure will aid in the treatment of intracardiac defects in selected patients weighing less than 10 kg with good early outcomes. (J Card Surg 2012;27:740-744) [ABSTRACT FROM AUTHOR]

Air-stable zirconocene bis(perfluoroctanesulfonate)s [Cp2Zr]OSO2C8F17)2] (1) with high Lewis acidity and high thermal stability was prepared by the reaction between Cp2ZrCl2 and AgOSO2C8F17. The as-prepared complex 1 exhibits good activity and selectivity in the cyclotrimerization of various ketones to the desired 1,3,5-triaylbenzenes. Furthermore, in the cyclic experiments, the complex 1 shows little loss of activity after 10 cycles. The results afford a general and efficient method for the cyclotrimerization of ketones using Cp2Zr(OSO2C8F17)2 as catalyst. [ABSTRACT FROM AUTHOR]

Abstract: This study presents a model-based control strategy for a novel dedicated outdoor air-chilled ceiling (DOAS-CC) system with the aim of optimizing the overall system performance. The DOAS-CC system incorporates liquid desiccant dehumidification and membrane-based total heat recovery technologies. Simplified but reliable models of major components in the DOAS-CC system are firstly developed to predict the system performance. A cost function is then constructed to minimize total energy consumption while properly maintaining thermal comfort reflected by indoor air temperature and relative humidity. Genetic algorithm is used to search for optimal set-points of the supply air temperature and humidity ratio of the dedicated outdoor air subsystem as well as the supply water temperature. The performance of this strategy is tested and evaluated with different control settings in a simulated multi-zone space served by the DOAS-CC system under various weather conditions. The results show that optimized control variables produced by the optimal strategy can improve the system energy performance and maintain indoor thermal comfort. [Copyright &y& Elsevier]

Abstract: In this paper, we report the synthesis, crystal structure, photophysical properties, and electronic nature of a phosphorescent Cu(I) complex of [Cu(Phen-Np)(POP)]BF4, where Phen-Np and POP stand for 2-(naphthalen-1-yl)-1H-imidazo[4,5-f][1,10]phenanthroline and bis(2-(diphenylphosphanyl)phenyl) ether, respectively. [Cu(Phen-Np)(POP)]BF4 renders a yellow phosphorescence peaking at 545nm, with a long excited state lifetime of 4.69μs. Density functional calculation reveals that the emission comes from a triplet metal-to-ligand-charge-transfer excited state. We electrospun composite nanofibers of [Cu(Phen-Np)(POP)]BF4 and polystyrene (PS), hoping to explore the possibility of using the composite nanofibers as an oxygen sensing material. The finally obtained samples with average diameter of ∼300nm exhibit a maximum sensitivity of 7.2 towards molecular oxygen with short response time of 7s due to the large surface-area-to-volume ratio of nanofibrous membranes. No photobleaching is detected in these samples. [Copyright &y& Elsevier]

Abstract: Hemp (Cannabis sativa L.) bast was used to prepare activated carbon fibers by phosphoric acid activation at 400–600°C. The pyrolysis process, textural and chemical properties for the samples were investigated by means of TG/DTA, SEM, cryogenic N2 adsorption, FTIR and XPS. Dye adsorption on the resultant sample was also measured. The textural properties of the activated carbon fibers were found to be strongly dependent on the activation temperature. Activated carbon fibers exhibited narrow pore size distributions with maxima in the micropore and small mesopore regions. BET surface area, total pore volume, micropore volume and mesopore volume increased with the increase of activation temperature up to 450°C and then decreased with further heating, and a sample with maximum surface area of 1142m2 g−1 and total pore volume of 0.67cm3 g−1 was obtained. Phosphoric acid facilitated the conservation of porous structure, led to the creation of tremendous porosity, and resulted in various P-containing functional structures on the surface and in the bulk phase of the resultant samples. The adsorption of acid blue 9 on the sample could be favorably described by Langmuir isotherm, and the adsorption kinetics was found to be well fitted by the intraparticle diffusion model. [ABSTRACT FROM AUTHOR]

Abstract: The use of phase change materials (PCM) to enhance the building energy performance has attracted increasing attention of researchers and practitioners over the last few years. Thermodynamic models of building structures using PCMs are essential for analyzing their impacts on building energy performance at different conditions and using different control strategies. There are few PCM models of detailed physics providing good accuracy in simulating thermodynamic behavior of building structures integrated with PCM layers. However, simplified models with acceptable accuracy and good reliability are preferable in many practical applications concerning computation speed and program size particularly when involving large buildings or models are used for online applications. A simplified physical dynamic model of building structures integrated with SSPCM (shaped-stabilized phase change material) is developed and validated in this study. The simplified physical model represents the wall by 3 resistances and 2 capacitances and the PCM layer by 4 resistances and 2 capacitances respectively while the key issue is the parameter identification of the model. The parameters of the simplified model are identified using genetic algorithm (GA) on the basis of the basic physical properties of the wall and PCM layer. Two GA-based preprocessors are developed to identify the optimal parameters (resistances and capacitances) of the model by frequency-domain regression and time-domain regression respectively. Validation results show that the simplified model can represent light walls and median walls integrated with SSPCM with good accuracy. [Copyright &y& Elsevier]

Abstract: Short time step heat flow calculation of building constructions is often needed for practical applications. Conventional methods such as state-space method and root-finding method may produce unstable conduction transfer function (CTF) coefficients at short time steps, and thus result in unstable heat flow calculation through building constructions. Frequency-domain regression (FDR) method is a newly developed method for computing CTF coefficients efficiently by representing the real building construction system with equivalent polynomial s-transfer functions. Previous studies on this method mainly addressed CTF coefficients at the conventional time step of 3600s and the performance of heat flow calculation using these coefficients. This paper presents the investigation on the performance of CTF coefficients at various short time steps based on FDR method, and the performance of the heat flow calculation using these coefficients. The results show that FDR method can produce stable CTF coefficients at various time steps for most building constructions, and the calculated heat flows using these coefficients are of high accuracy. [Copyright &y& Elsevier]

Abstract: This paper presents a robust model predictive control strategy for improving the supply air temperature control of air-handling units by dealing with the associated uncertainties and constraints directly. This strategy uses a first-order plus time-delay model with uncertain time-delay and system gain to describe air-conditioning process of an air-handling unit usually operating at various weather conditions. The uncertainties of the time-delay and system gain, which imply the nonlinearities and the variable dynamic characteristics, are formulated using an uncertainty polytope. Based on this uncertainty formulation, an offline LMI-based robust model predictive control algorithm is employed to design a robust controller for air-handling units which can guarantee a good robustness subject to uncertainties and constraints. The proposed robust strategy is evaluated in a dynamic simulation environment of a variable air volume air-conditioning system in various operation conditions by comparing with a conventional PI control strategy. The robustness analysis of both strategies under different weather conditions is also presented. [Copyright &y& Elsevier]