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Background: Bariatric surgery is an effective treatment for morbid obesity. However, a subset of individuals seeking bariatric surgery may exhibit a metabolically healthy obesity (MHO) phenotype, suggesting that they may not experience metabolic complications despite being overweight. Objective: This study aimed to determine the prevalence and metabolic features of MHO in a population undergoing bariatric surgery. Methods: A representative sample of 665 participants aged 14 or older who underwent bariatric surgery at our center from January 1, 2010 to January 1, 2020 was included in this cohort study. MHO was defined based on specific criteria, including blood pressure, waist-to-hip ratio, and absence of diabetes. Results: Among the 665 participants, 80 individuals (12.0%) met the criteria for MHO. Female gender (P =.021) and younger age (P <.001) were associated with a higher likelihood of MHO. Smaller weight and BMI were observed in individuals with MHO. However, a considerable proportion of those with MHO exhibited other metabolic abnormalities, such as fatty liver (68.6%), hyperuricemia (55.3%), elevated lipid levels (58.7%), and abnormal lipoprotein levels (88%). Conclusion: Approximately 1 in 8 individuals referred for bariatric surgery displayed the phenotype of MHO. Despite being metabolically healthy based on certain criteria, a significant proportion of individuals with MHO still exhibited metabolic abnormalities, such as fatty liver, hyperuricemia, elevated lipid levels, and abnormal lipoprotein levels, highlighting the importance of thorough metabolic evaluation in this population. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study is to investigate the epidemiological features, clinical characteristics, and pathological characteristics of acral lentiginous melanoma (ALM) and identify prognostic factors. Methods: A total of 149 patients diagnosed with ALM between August 2008 and December 2019 at the National Cancer Center (NCC) of China were retrospectively analyzed. Follow-up data on patient survival status were collected. Survival curves were generated using the Kaplan-Meier method, and statistical significance was assessed using the log-rank test. Additionally, a Cox proportional hazards model was constructed to identify prognostic factors. Results: All patients included in this study were of Chinese ethnicity, with an average age of 52.4 ± 14.8 years (range, 15-80 years) at the time of diagnosis. No gender predilection or genetic susceptibility was observed. The plantar region was the most frequently affected site among primary lesions. Notably, only 17 (11.4%) patients reported a history of trauma. Statistical analysis revealed that a lesion duration of ≤2.5 years, Breslow thickness >4.0 mm, high mitotic rate (>6 mm−2), presence of vascular invasion, and regional lymph node metastasis were identified as independent prognostic factors. Conclusion: Our findings indicate that a lesion duration of ≤2.5 years, Breslow thickness >4.0 mm, high mitotic rate (>6 mm−2), presence of vascular invasion, and regional lymph node metastasis are significantly associated with a poorer prognosis for patients with ALM. [ABSTRACT FROM AUTHOR]

As a vital infrastructure in modern cities, district heating (DH) systems provide stable high-quality heat sources. To satisfy the demands of energy-saving, emission-reduction policies, and user preferences, a high-precision digital simulation platform is essential for district heating network (DHN) scheduling. In this paper, a method for digital twin (DT) modeling based on hydraulic resistance identification using an online adaptive particle swarm optimization (APSO) algorithm is proposed. Additionally, Singular Spectrum Analysis and back propagation artificial neural network algorithms (SSA-BP) are proposed to achieve heat load prediction in order to provide sufficient conditions for DHN scheduling. The load prediction for the substation is completed by predicting the secondary return water temperature at the subsequent time step based on the historical outdoor temperature time series and secondary supply water temperature of the substation. Accordingly, simulation analysis has been conducted on its application to an existing DHN in Tianjin. With the proposed methods, the simulation errors are reduced for about 80 % substations in the case DHN compared to mechanistic models when simulating hydraulic conditions. Among these, 77.49 % of substations were reduced by 0 %–3 %, and 1.43 % of substations were reduced by 3 %–5 %. The prediction errors of secondary return water temperature for case substations A and B exhibit random variation trends, with maximum absolute errors within the range of 0.02 °C and 0.06 °C, respectively. • Digital twin modeling of a large-scale complex district heating network through hydraulic resistance identification. • Heat load prediction of substations based on singular spectrum analysis and back propagation artificial neura network algorithms. [ABSTRACT FROM AUTHOR]

A novel composite film with efficient removal of anionic dye (Congo red) was developed using chitosan and dialdehyde microfibrillated cellulose nano fibrils. Microfibrillated cellulose with three dimensional network structure was prepared from microcrystalline cellulose by high-pressure homogenization. Then it was surface modified by periodate to prepare dialdehyde microfibrillated cellulose (DAMFC). DAMFC/chitosan composite films were prepared by solvent-casting. During the compounding of DAMFC with chitosan, a Schiff base was formed through the reaction between the aldehyde groups of DAMFC and amino groups of chitosan. A giant network structure was therefore formed. The addition of DAMFC resulted in remarkably increased adsorption capacity of the chitosan material as well as drastically improved stability in dye solution. The adsorption performance was investigated with respect to pH, temperature, contact time, and the initial dye concentration. The possible adsorption mechanism was proposed. Various isotherm models have been used to fit the data, and kinetic parameters were evaluated. [ABSTRACT FROM AUTHOR]

District heating (DH) networks are indispensable infrastructure for space and domestic heating with high energy efficiency. As the structures of DH networks are gradually becoming complex, efficient and accurate simulation model for the operational optimization of the DH network is crucial. In this paper, an optimization method for the DH network operation is proposed. The method is based on the thermo-hydraulic coupled dynamic model, sequential quadratic programming (SQP) and particle swarm optimization (PSO), which is applied to a large-scale DH network in Tianjin, China. With the proposed method, 6.7%∼11% energy consumption can be reduced, under the operation condition of 80%∼100% design flow rate. The transmission and distribution cost can be reduced with an average of 6.2% at the outdoor temperature ranging from −5 to 5 °C. • Thermo-hydraulic condition optimization of a large-scale complex district heating network. • Model validation with operation data of the district heating network. • The transmission and distribution costs and energy consumption of the case DH network are simulated and optimized. [ABSTRACT FROM AUTHOR]

Renewable energy (RE) sources are important alternatives to mitigate the energy crisis and achieve sustainable development. Appropriate selection of RE system solutions is extremely crucial. Selection of the best RE technology requires the consideration of conflicting qualitative and quantitative evaluation criteria. Many evaluation criteria are judged with subjectivity and uncertainty. However, the description of uncertainty in the evaluation process remains a large research gap. Therefore, a novel combined evaluation method is developed to describe and visualize the uncertainty in the assessment process. The proposed evaluation method is tested for RE heating system selection. The RE systems are evaluated based on five dimensions and 15 evaluation indicators. This multidimensional indicator framework not only includes the three basic evaluation groups of energy, economy, and environment, but also extends to the performance of technology and policy. The combined weights of the evaluation indicators consist of objective weights and subjective weights. The objective weights are obtained by the Criteria Importance Through Intercriteria Correlation (CRITIC) method and subjective weights are calculated by the improved Fuzzy Analytic Hierarchy Process (FAHP). The set pair analysis (SPA) is introduced to assess the performance of different RE systems. It considers the uncertainty of indicator performance. A novel approach to visualizing the fuzziness of SPA evaluation is developed using the cloud model. Finally, the RE system ranking calculated by the proposed method is performed. The originality of this work is offering a promising method for RE selection and clarifying the degree of ambiguity in the evaluation process. It helps decision makers have an exact idea about the accuracy of the evaluation. It provides insights into multi-objective decision-making problems. • A multidimensional evaluation framework for renewable heating systems is proposed. • The integrated weights of the criteria are obtained by the CRITIC and FAHP method. • The ranking of the renewable heating systems is obtained by set pair analysis. • Uncertainties in the evaluation process are described and visualized by cloud model. [ABSTRACT FROM AUTHOR]

Continuously learning new tasks using high-level ideas or knowledge is a key capability of humans. In this paper, we propose lifelong reinforcement learning with sequential linear temporal logic formulas and reward machines (LSRM), which enables an agent to leverage previously learned knowledge to accelerate the learning of logically specified tasks. For a more flexible specification of tasks, we first introduce sequential linear temporal logic (SLTL), which is a supplement to the existing linear temporal logic (LTL) formal language. We then utilize reward machines (RMs) to exploit structural reward functions for tasks encoded with high-level events, and propose an automatic extension of RMs and efficient knowledge transfer over tasks for continuous lifelong learning. Experimental results show that LSRM outperforms methods that learn the target tasks from scratch by taking advantage of the task decomposition using SLTL and the knowledge transfer over RMs during the lifelong learning process. [ABSTRACT FROM AUTHOR]

Reflecting on the sharp contradictions between energy and environmental concerns, nowadays, a critical theme is to strengthen the role of renewables for heating. The majority of current renewable energy (RE) studies are for power generation, research at the macro level, with subjective evaluation methods. Aimed at filling the niche, this paper proposes an integrated approach involving the investigation of renewable energy (solar, geothermal and biomass) heating potentials, the evaluation of suitability at the county level, and the guidance of targeted policies. Accordingly, the factor analysis, an objective statistical analysis method, is employed to concentrate information and score appropriateness based on the county development level, population quality, government support and renewable resource potentials. Subsequently, the comprehensive scores for counties are categorized into four classes by self-organizing maps. In this study, a novel approach for evaluating the RE heating potentials and identifying the constraints of RE development is proposed. The heating demand and the potentials of renewables are determined on a detailed and precise scale at the county level, and the heating supply-demand is mapped with symbol sizes. Finally, specific recommendations for renewables energy development are put forward from a local planning perspective. The application of this systematic approach, which can be broadly exported and applied to other regions, will promote a strong commitment to renewable energy and significantly accelerate the transition to a clean energy supply. • Evaluate the suitability of renewable energy heating at a detailed scale. • Integrated renewable energy suitability scores are derived by the factor analysis. • The development indicators are categorized into four classes by the SOM method. • Regional development characteristics are identified by the extracted factors. • Targeted renewable energy development policies are proposed. [ABSTRACT FROM AUTHOR]

Highlights: [•] Pumping water temperature is much dependent on seawater temperature. [•] Pumping water temperature decreases with the lessening of pumping flow rate. [•] Pumping water temperature decreases with the beach well diameter becoming larger. [Copyright &y& Elsevier]

Long-distance district heating pipelines (LDHPs) are important infrastructures in large scale district heating (DH) system. Their safety and stability are crucial for stable and efficient operation of the whole DH system. Pipeline leakage is a common accident in the operation of DH system, accurate and fast leak detection technique is an indispensable measure for ensuring efficient repair and avoiding large-area heating failure. In this paper, a fast and accurate leak detection technique for LDHPs is proposed. The technique utilizes the numerical hydraulic transient model of the LDHP and the particle swarm optimization (PSO) algorithm to find the leak point. A pressure wave velocity identification procedure is also established for the leak detection. Simulation tests are conducted on a 20 km LDHP to investigate the influences of instrumental error and sampling frequency of measured data on the accuracy of the leak detection. Results show that when the sampling frequency is higher than 0.1 Hz, the relative errors of the detected leak point areas and leak point positions can be less than 2.73 % and 2.40 %, respectively. Effective leak detection of LDHPs can be therefore conducted through the proposed leak detection technique and measuring instruments with high precision and proper sampling frequency. • A hydraulic transient model of LDHP system based on DPM is established. • The time and spatial step independence verification of the model is conducted. • A novel pressure wave velocity identification approach for LDHP is proposed. • A fast and accurate leak detection technique of LDHP is established. • Performances of proposed approaches are analyzed and verified through simulation. [ABSTRACT FROM AUTHOR]

Numerical simulation of district heating network (DHN) is essential for analysis and operational optimization of the DHN. The complex topology and large scale of the DHN lead to difficulties in the thermo-hydraulic coupled simulation. In this paper, the thermo-hydraulic coupled simulation model of a real large-scale DHN with multiple heat sources in Tianjin is established, and the actual operation data of the DHN is monitored for model validation. Results show that the relative errors of the hydraulic and thermal simulation are within ±8% and ±5%, respectively. The operation condition and energy consumption of the DHN during the heating period are analyzed with the proposed model. As the heating load increases, the heat loss ratio (HLR) and the energy consumption and heating ratio (EHR) decrease. The average HLR of the DHN is 10.1% and the average EHR is 0.0086. • Thermo-hydraulic coupled modeling of a real large-scale district heating network. • Model validation with operation data of the district heating network. • Operation condition and energy consumption analysis of the network. [ABSTRACT FROM AUTHOR]

Abstract: Native skin collagen fibers were successfully dissolved in the ionic liquid, 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), and regenerated in different precipitators. The observation by polarized optical microscopy showed that the crystal structure of collagen fibers had been destroyed by [BMIM]Cl during the heating. Temperature-dependent FTIR was applied to detect the structural change of collagen/[BMIM]Cl during dissolving. The structure of regenerated collagen was characterized by FTIR and XRD. It showed that the triple helical structure of collagen had been partly destroyed during the dissolution and regeneration. The film forming ability and the thermostability of the regenerated collagen was highly dependent on the precipitating treatment. The possible mechanisms of dissolving of collagen in [BMIM]Cl and the regeneration in the precipitators have been proposed. The collagen/cellulose composite with different forms (film, fiber, gel) can be successfully prepared by using [BMIM]Cl as medium. [Copyright &y& Elsevier]

As a critical transportation infrastructure, with a high flow of people and high-energy consumption in China, coach stations have great potential in energy saving and CO2 emission reduction. In this paper, the building information and energy consumption data of 29 coach stations in five climate regions of China were obtained by field investigations. The annual total comprehensive building energy consumption was 31.37–128.08 kWh/(m2·a). The annual total CO2 emissions from building operation in the coach stations was 17.01–134.77 kgCO2/(m2·a). The heating, ventilation and air conditioning (HVAC) system was the largest energy using and CO2 emissions sector: 30.42–72.47% of the energy consumption and 30.42–83.93% of the CO2 emissions were generated by HVAC system. The energy consumption and CO2 emission level of coach stations and that of other kinds of public buildings were compared. Results showed that the energy consumption and CO2 emission levels of coach stations investigated were relatively low, mainly because the passenger thermal comfort was scarified. Based on the investigation data, energy consumption analysis models of coach stations in five regions were established by simulation when the passenger thermal comfort was met. The potentials of energy saving and CO2 emission reduction were studied from forms of the HVAC system, heat recovery and natural illumination. [ABSTRACT FROM AUTHOR]

• Integrated SHC system driven by PTC and double-effect absorption chiller. • Mathematical model establishment and validation of the whole system. • Comparison of the SHC system and the conventional gas-driven absorption heating and cooling system. • Annual performance investigations and assessments of the SHC system. With the increasing concerns on energy conservation and environmental protection, solar heating and cooling (SHC) system represents an attractive candidate in building sector. In this paper, an integrated SHC system driven by parabolic trough collector (PTC) and double-effect H 2 O/LiBr absorption chiller was presented. The energy generated by solar collectors was supplied to the absorption chiller during the cooling period, and was directly used for space heating with the integration of plate heat exchanger during the heating period. The mathematical models of the whole system including the collector, the double-effect absorption chiller and the plate heat exchanger were established and were validated by field tests. Based on the proposed models, comparison of the SHC system and the conventional gas-driven absorption heating and cooling system was carried out by case study. The annual performances as well as energetic, economic and environmental assessments of the proposed system were investigated. Results show that, 21.3% of the primary energy consumption and 18.8% of the CO 2 emission can be reduced in SHC system. Therefore, the proposed integrated solar heating and cooling system has a promising application prospect in sustainable development in view of its considerable energy saving benefits, potential economic viability and environmental friendly characteristics. [ABSTRACT FROM AUTHOR]

The present work investigates the effects of nano-chitin with different charge, obtained by acid hydrolysis and TEMPO oxidation, on the structure and properties of borax crosslinked polyvinyl alcohol (PVA) hydrogels. In detail, nano-chitin prepared by acid hydrolysis (ACh) is positively charged (+28.8 mV). The electrostatic attraction between ACh and borax ions leads to a maximum tensile stress of composite hydrogel (ACh/PB), 54.25 KPa, 17 times of the borax crosslinked PVA (PB). In contrast, nano-chitin prepared by TEMPO-oxidation (TCh) shows negative charge (−59.0 mV). Due to the electrostatic repulsion with borax ions, the maximum tensile stress of composite hydrogel (TCh/PB) is only 9.25 KPa, a very limit reinforcing effect. However, TCh/PB showed better self-healing efficiency (96.0 %) as well as ionic conductivity (1.25 × 10−5 S/m). The present work shows that the charge state of the nano-chitin exerts great influence on the interaction with the crosslinking agent borax, therefore, affects the structure and properties of the final PVA composite hydrogels. The results could provide important information about making full use of nano-chitin as a reinforcement by adjusting its surface charge state. [Display omitted] • Nano-chitin prepared by acid hydrolysis and TEMPO oxidation have different charge state. • The reinforcing effect of nano-chitin on PVA hydrogels is significantly influenced by its surface charge state. • The self-healing performance and ionic conductivity are also affected. [ABSTRACT FROM AUTHOR]

[Display omitted] • Soluble soybean polysaccharide (SSPS) films were crosslinked with citric acid (CA). • CA-crosslinked SSPS films exhibited enhanced mechanical, barrier, thermal, and antioxidant properties. • CA-crosslinking endows SSPS films with excellent antibacterial performance. • The CA-crosslinked SSPS films effectively extended the shelf life of lard. In this work, a nontoxic crosslinking agent, citric acid (CA), was used to crosslink glycerol-plasticized SSPS films via a heat activated reaction. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy results confirmed the occurrence of esterification reaction between CA and SSPS. Microstructure of the CA-crosslinked SSPS films were characterized by scanning electron microscopy, atomic force microscopy and X-ray diffraction. The water resistance, mechanical, UV-barrier, water vapor barrier, antioxidant and thermal properties of SSPS films were enhanced by CA crosslinking. The SSPS film crosslinked with 5 % CA exhibited a maximum tensile strength of 6.5 MPa and a minimum water solubility of 34.3 %. The CA-crosslinked SSPS film also presented superior antibacterial properties against Gram-positive and Gram-negative bacteria. Application test results showed that the CA-crosslinked SSPS film can effectively delay the oxidative deterioration of lard during storage, suggesting that the developed CA-crosslinked SSPS film could be a promising candidate for active food packaging. [ABSTRACT FROM AUTHOR]

Nanocomposite films of soluble soybean polysaccharide (SSPS)/nano zinc oxide (nZnO) reinforced with microfibrillated cellulose (MFC) were developed by solvent casting method. The structure, optical, barrier, thermal, surface wettability, mechanical properties and antimicrobial activity of the SSPS/MFC, SSPS/nZnO and SSPS/nZnO/MFC nanocomposite films were evaluated. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra indicated interactions between SSPS and the nano-fillers. The nanocomposite films containing MFC showed improved tensile strength, stiffness, ultraviolet (UV) light barrier property, thermal stability and water resistance when compared with the neat SSPS film. The nZnO-incorporated nanocomposite films exhibited good antimicrobial activity against E. coli and B. subtlis. Overall, the MFC-reinforced SSPS/nZnO nanocomposite films possessed desirable characteristics to be considered as potential candidates for antimicrobial packaging and biomedical applications. Unlabelled Image • Soluble soybean polysaccharide based nanocomposite films were prepared. • Microfibrillated cellulose improved mechanical properties of the films. • Nanocomposites exhibited improved UV-shielding property and thermal stability. • The ZnO-containing nanocomposites showed good antimicrobial activity. [ABSTRACT FROM AUTHOR]

Self-renewing, damage–repair and differentiation of mammalian stratified squamous epithelia are subject to tissue homeostasis, but the regulation mechanisms remain elusive. Here, we investigate the esophageal squamous epithelial tissue homeostasis in vitro and in vivo. We establish a rat esophageal organoid (rEO) in vitro system and show that the landscapes of rEO formation, development and maturation trajectories can mimic those of rat esophageal epithelia in vivo. Single-cell RNA sequencing (scRNA-seq), snapshot immunostaining and functional analyses of stratified “matured” rEOs define that the epithelial pluripotent stem cell determinants, p63 and Sox2, play crucial but distinctive roles for regulating mammalian esophageal tissue homeostasis. We identify two cell populations, p63+Sox2+ and p63−Sox2+, of which the p63+Sox2+ population presented at the basal layer is the cells of origin required for esophageal epithelial stemness maintenance and proliferation, whereas the p63−Sox2+ population presented at the suprabasal layers is the cells of origin having a dual role for esophageal epithelial differentiation (differentiation-prone fate) and rapid tissue damage–repair responses (proliferation-prone fate). Given the fact that p63 and Sox2 are developmental lineage oncogenes and commonly overexpressed in ESCC tissues, p63−Sox2+ population could not be detected in organoids formed by esophageal squamous cell carcinoma (ESCC) cell lines. Taken together, these findings reveal that the tissue homeostasis is maintained distinctively by p63 and/or Sox2-dependent cell lineage populations required for the tissue renewing, damage–repair and protection of carcinogenesis in mammalian esophagi. [ABSTRACT FROM AUTHOR]

• A high-strength pullulan dialdehyde (PDA) crosslinked gelatin hydrogel was synthesized. • The hydrogel strength was adjusted by controlling the concentration of PDA. • The swelling and enzymatic degradation of the hydrogel were limited by PDA crosslinking. • The hydrogel exhibited non-cytotoxicity. Herein the construction of a strong gelatin hydrogel is presented by using pullulan dialdehyde (PDA) as a macromolecular crosslinker. The resultant PDA crosslinked gelatin hydrogels (G-PDA) exhibit extremely high mechanical strength, manifested in the achieved optimal compressive stress of 5.80 MPa at 80% strain, which is up to 152 times higher than pure gelatin hydrogel. The G-PDA were characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The extent of crosslinking was determined by ninhydrin assay. The results suggested that the synergistic effect of dual-crosslinking, which is composed of short- and long-range covalent crosslinking and thermoreversible physical crosslinking, may played a key role in enhancing the load-bearing capacity of ensuing hydrogels. The swelling and enzymatic degradation of G-PDA are gradually limited with increasing PDA concentration. The result from MTT assay demonstrated that G-PDA is non-cytotoxic against MC3T3 cells, regardless of the concentrations of PDA. [ABSTRACT FROM AUTHOR]

The development of high‐performance and low‐cost, flexible electronic devices is a crucial prerequisite for emerging applications of energy storage, conversion, and sensing system. Collagen as the most abundant structural protein in mammals, owing to the unique amino acid composition and hierarchical structure, the conversion of collagen into collagen‐derived carbon materials with different nanostructures and abundant ideal heteroatom doping through the carbonization method is expected to be a promising candidate material for electrodes of energy storage devices. The excellent mechanical flexibility of collagen and the abundant functional groups on its molecular chain that are easy to modify provide the possibility to be used as a separator material. On this basis, the ideal biocompatibility and degradability provide unique conditions for it to match the flexible substrate material of the human body for wearable electronic skin. In this review, the unique characteristics and advantages of collagen for electronic devices are first summarized. Recent progress in designing and constructing collagen‐based electronic devices for future applications of electrochemical energy storage and sensing are reviewed. Finally, the challenges and prospects for collagen‐based flexible electronic devices are discussed. [ABSTRACT FROM AUTHOR]

Since radiator takes an important role in controlling indoor air temperature and heat output of district heating system, efficient control of radiator is essential for thermal comfort and energy conservation. The governing equation of radiator heat transfer is a partial differential equation (PDE), which is not suitable for controller design. In this paper, an accurate model reduction method was established to reduce the radiator model. Comparison of the reduced and PDE models via Bode diagrams shows good approximation of the reduced model. The integrated model of room heating system was developed based on the reduced radiator model. In order to enhance the dynamic performance of room heating system, a new control algorithm, the two-degrees-of-freedom H ∞ control was proposed. The reference tracking and disturbance rejection performances of room heating system with H ∞ and PI controllers were compared. Dynamic performances of closed-loop system controlled by the two control algorithms under capacity parameter uncertainties were analyzed to verify the robustness of the proposed control algorithm. Results show that the proposed two-degrees-of-freedom H ∞ controller can ensure better reference tracking and disturbance rejection performances even when system uncertainty exists. [ABSTRACT FROM AUTHOR]

Herein, a strong and stable gelatin-based composite hydrogel was fabricated by incorporation of amino-functionalized microfibrillated cellulose (AMFC) into gelatin matrix along with genipin crosslinking. The hydrogel consists of chemical and physical crosslinks among gelatin chains and AMFC fibrils. The morphology, swelling behavior and compressive properties of the composite hydrogels were investigated. The results show that the mechanical properties and structural stability of the gelatin hydrogels were improved remarkably by the addition of AMFC due to the formation of a hybrid network structure. The composite hydrogel has a compressive strength up to 1.52 MPa at a strain of 80 %, which is 41.2 and 1.8 times higher than that of the conventional physical and genipin-crosslinked gelatin hydrogels, respectively. Moreover, the developed gelatin-based composite hydrogels reinforced with AMFC exhibit good enzymatic stability, high surface hydrophobicity, tunable swelling property and excellent biocompatibility, which are expected to have potential applications in biomedical and pharmaceutical fields. [Display omitted] • Amino-functionalized microfibrillated cellulose (AMFC) was synthesized. • AMFC addition improves the mechanical properties of gelatin-based hydrogel. • The hydrogels have tunable swelling and enzymatic degradation behaviors. • The hydrogels containing AMFC exhibit hydrophobicity and non-cytotoxicity. [ABSTRACT FROM AUTHOR]

To investigate the status quo of heating supply and the impact of energy saving policies in northern China, a survey was conducted on the DHSs (district heating systems) in 15 Chinese cities. The average heating energy consumption was 19.2% lower than in 2008 due to the corresponding policies formulated and promoted by the authorities. Additionally, parameters of DHSs in cold and severe cold zones were collected, which include the energy consumption, operating efficiency, monitoring and control level, and gas emissions. These essential data can serve as a reference for energy efficiency retrofits and further analysis of comprehensive energy consumption of the DHSs in northern China. Finally, suggestions for improving existing policies during “the Twelfth Five-Year Plan” period are put forward to further improve the energy efficiency of DHSs. [ABSTRACT FROM AUTHOR]

[Display omitted] • An acid treatment/pyrolysis combined method was proposed for disposing of CTLS. • Acid treatment affects kinetics and evolved gases of CTLS pyrolysis. • Acid treatment increases the yields of aliphatic hydrocarbons and NH 3. • Pyrolysis mechanism can be described by random nucleation and nuclei growth model. Management and safe disposal of chrome-tanned leather wastes generated in leather industry are of great importance due to their potential health risks and environmental hazards. Herein, an integrated strategy was proposed for disposing of chrome-tanned leather scrap (CTLS). This method involves the separation of chromium salts from CTLS with sulfuric acid for recycling purpose, followed by pyrolysis of the acid-treated CTLS in an inert atmosphere. SEM/EDX analysis was employed to characterize the changes in composition and morphology of CTLS after acid treatment. CO 2 and H 2 O are main pyrolysis gases of CTLS, while the acid treatment increases the relative content of aliphatic hydrocarbons and NH 3 in evolved gases. The pyrolysis characteristics and kinetics of the acid-treated CTLS were investigated by thermogravimetric analysis (TGA) at three different heating rates. After 3 and 6 days of acid treatment, the average activation energy of CTLS (450.9 kJ/mol) obtained from the Flynn-Wall-Ozawa method decreased to 369.6 and 351.0 kJ/mol, respectively. It is assumed that the CTLS consists of two pseudocomponents: low-crosslinked collagen (LCol) and highly-crosslinked collagen (HCol). Using the generalized master plots method, random nucleation and nuclei growth model (An model) was found to be the most probable kinetic model for the pyrolysis process of LCol and HCol. The kinetic exponent for pseudocomponent pyrolysis varied between 3.00 and 3.90, and the pre-exponential factor ranged from 5.83 × 1012 to 2.93 × 1013 min−1. The results of the present study provide an alternative route and useful information for recycling and disposing of chrome-containing leather wastes. [ABSTRACT FROM AUTHOR]

Complex coacervation of polysaccharides and proteins is a liquid-liquid phase separation that can occur when they are oppositely charged in aqueous solution. In the present work, soluble soybean polysaccharide (SSPS) and fish gelatin (FG) edible blend films were prepared through pH-induced complex coacervation. The optimal SSPS-to-FG mass ratio (1:3) and pH (5.0) conditions for complex coacervation was determined by measuring the maximum turbidity of SSPS/FG mixtures. The effect of SSPS-FG coacervates on microstructure and properties of SSPS/FG blend films were investigated. Results indicated that the film surface roughness and water contact angle were increased due to the presence of coacervates, while the water vapor permeability and Young's modulus were decreased. The SSPS/FG films containing coacervates had similar optical properties, tensile strength, heat seal ability and water sensitivity but improved thermal stability than the coacervate-free SSPS/FG films. When curcumin was incorporated into SSPS/FG films as an active ingredient, the complex coacervates effectively delayed the release of curcumin from the blend films into lipophilic food simulants. Thus, SSPS/FG blend films fabricated by complex coacervation could serve as potential substrates for developing active food packaging materials with satisfactory properties. [Display omitted] • SSPS/FG blend films were developed through complex coacervation. • Optimal conditions for complex coacervation were determined. • Complex coacervates enhance SSPS/FG film's barrier and thermal properties. • Complex coacervates delay curcumin release from SSPS/FG films in food simulants. [ABSTRACT FROM AUTHOR]

Frosting on the coil of the air source heat pump (ASHP) significantly affects its performance. An accurate defrosting control method is essential for the ASHP unit. Here, a novel visual defrosting control method based on machine vision is proposed. The frosting degree of the unit is accurately obtained by frosting image analysis with digital image processing to achieve on-demand defrosting. Fractal dimension, frosting degree coefficient, and single-circuit frosting evenness value are introduced to evaluate the frosting degree of coil images. The image acquisition point is determined with confusion matrix. Based on this, the logical framework of the proposed method is constructed, in which the defrosting starting and termination conditions are set as the moment when the frosting degree coefficient is equal to 0.9 and 0, respectively. A multi-variable model of fractal dimension is fitted, which improves the generalization of the proposed method. Finally, comparative experiments are conducted between the proposed method and the traditional temperature-time (T-T) method in typical cases. The results indicate that the COP and total heating capacity increase by 11.8 %, 10.6 % and 7.4 %, 6.6 %, respectively, and the defrosting frequency is reduced by 75 %, which demonstrates dominant advantages of the proposed method in accuracy, energy-saving, and indoor thermal comfort management. • A novel visual defrosting control method based on machine vision is proposed. • Microscopic image acquisition point is selected by multi-case statistical analysis. • The defrosting control conditions are determined by frosting degree coefficient. • Comparative experiments are conducted between T-T method and the novel method. [ABSTRACT FROM AUTHOR]

Rat model of N-nitrosomethylbenzylamine (NMBzA)-induced esophageal squamous cell carcinoma (ESCC) is routinely used to study ESCC initiation, progression and new therapeutic strategies. However, the model is time-consuming and malignant tumor incidences are low. Here, we report the usage of multi-kinase inhibitor sorafenib as a tumor promoter to establish an efficient two-stage NMBzA-induced rat ESCC carcinogenesis model, resulting in increments of tumor incidences and shortened tumor formation times. By establishing the model and applying whole-genome sequencing, we discover that benign papillomas and malignant ESCCs harbor most of the "driver" events found in rat ESCCs (e.g. recurrent mutations in Ras family, the Hippo and Notch pathways and histone modifier genes) and the mutational landscapes of rat and human ESCCs overlap extensively. We generate tumor cell lines derived from NMBzA-induced papillomas and ESCCs, showing that papilloma cells retain more characteristics of normal epithelial cells than carcinoma cells, especially their exhibitions of normal rat cell karyotypes and inabilities of forming tumors in immunodeficient mice. Three-dimensional (3-D) organoid cultures and single cell RNA sequencing (scRNA-seq) indicate that, when compared to control- and papilloma-organoids, ESCC-organoids display salient abnormalities at tissue and single-cell levels. Multi-omic analyses indicate that NMBzA-induced rat ESCCs are accompanied by progressive hyperactivations of the FAT-Hippo-YAP1 axis and siRNA or inhibitors of YAP1 block the growth of rat ESCCs. Taken together, these studies provide a framework of using an effective rat ESCC model to investigate multilevel functional genomics of ESCC carcinogenesis, which justify targeting YAP1 as a therapeutic strategy for ESCC. • Rat NMBzA/sorafenib induced two-stage carcinogenesis model elucidate the initiation and progression of ESCC. • Demonstration of NMBzA-induced rat papilloma and carcinoma cells acquired similar genomic mutation landscapes. • Rat esophageal papilloma (REP) cell lines retain similar characteristics of normal cells at organoid and single cell levels. • Rat esophageal squamous carcinoma (RESC) cell lines display malignant phenotypes at the tissue and single cell levels. • Alteration of FAT-Hippo-YAP axis is involved in regulating ESCC carcinogenesis progression. [ABSTRACT FROM AUTHOR]

A hybrid hydrogel system (GSOHA) consisting of serotonin-grafted gelatin and oxidized hyaluronic acid (OHA) was developed in this study to efficiently control bleeding and prevent bacterial infections during surgery and trauma. The study results showed that the incorporation of serotonin successfully produced hydrogels with rapid hemostatic, antibacterial, and antioxidant properties. The GSOHA hydrogel exhibited considerably stronger tissue adhesion (15.55 ± 0.36 kPa) to porcine skin than the commercial fibrin glue (1.09 ± 0.04 kPa). In addition, the hydrogel could rapidly absorb blood cells and stimulate cell conjugation with serotonin addition. In vitro experiments using endothelial cells and erythrocytes demonstrated the excellent biocompatibility and hemocompatibility of the hydrogel. Most importantly, the GSOHA hydrogel accelerated the wound healing process in a full-thickness skin defect mice model, and the histological staining results demonstrated that GSOHA significantly promoted collagen deposition and vascularization. In conclusion, this study demonstrated the significant potential of the GSOHA hydrogel as an adhesive dressing for rapid hemostasis and wound healing. [ABSTRACT FROM AUTHOR]

• The synergistic effect of temperature and relative humidity on the deterioration of mimosa-tanned leather was investigated. • The changes in structure and thermal properties of artificially aged mimosa-tanned leather were systematically studied. • The TG-FTIR technique was employed to analyze the deterioration with the evolved gaseous products during thermal degradation. The deterioration of mimosa-tanned leather artificially aged at 80 °C and 60% relative humidity (RH) for up to 32 days was investigated. The changes in thermal properties, morphology, and structure were analyzed by thermogravimetric analyzer (TGA), polarized light microscopy (PLM), scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray diffraction (XRD). The results showed that the mimosa-tanned leather was deteriorated with a decrease in hydroxyproline content. After the artificial aging treatment, the thermal resistance of the mimosa-tanned leather was reduced. This result was further confirmed by PLM observations that the shrinkage temperature of the collagen fibers decreased with increasing aging time. The evolved gaseous products from the TGA were detected by TGA-FTIR to characterize the deterioration caused by aging. After aging, the evolution yield of nitrogen-containing products such as NH 3 , HNCO, and pyrrole decreased, while the evolution yield of CO 2 increased. According to the ATR-FTIR, XRD, and SEM results, the orientation and structural integrity of the collagen fibers were destroyed by artificial aging. [ABSTRACT FROM AUTHOR]

A highly hydrophobic and self-recoverable sponge was prepared with cellulose nanofibrils (CNFs), N-alkylated chitosan (NCS), and poly (vinyl alcohol) (PVA), which was then endowed with hydrophobic properties via simple thermal chemical vapor deposition (CVD). The three-dimensional (3D) interconnected microstructure of the prepared CNF/NCS/PVA sponge was found to have 96% porosity, ultra-low density (16.61–50.91 mg/cm3) and high hydrophobicity (water contact angle of 147°), which can absorb various organic solvents with an absorption capacity of 19.05–51.08 times of its original weight. Besides, the sponge could bear 80% strain and be cyclically compressed 50 times under the strain of 50%. The sponge can effectively separate oil/water mixtures and water-in-oil emulsions with high separation efficiency and fluxes. Moreover, the sponge could keep its good stability in various acidic, saline and mechanical abrasion conditions. The green preparation and good separation efficiency suggest a potential application of recyclable and versatile CNF/NCS/PVA sponges in oil/water separation. [Display omitted] • The hydrophobic and self-recoverable sponge based on polysaccharides was prepared via a green way. • The sponge could withstand a good recoverable deformation under the strain of 80%. • The sponge possessed good stability under harsh conditions. • The sponge exhibited excellent selective and versatile oil/water separation. [ABSTRACT FROM AUTHOR]

Ethanol was used to induce coacervation in aqueous solutions of gelatin. Coacervation resulted from phase separation driven by ethanol as a poor solvent for gelatin, impacting aggregation of gelatin chains. Static coacervation was performed to investigate coacervate morphology, and gelatin concentration and ethanol temperature influenced the morphologies of the gelatin coacervates. High-concentration gelatin solutions (>4.8 wt%) treated with lower temperature ethanol (<25 °C) formed network morphologies, while low-concentration gelatin solution (<4.8 wt%) treated with ethanol near room temperature formed nanosphere assemblies. Dispersive nanospheres were obtained after treatment with higher temperature ethanol (~45 °C). Stirring the mixture of gelatin solution and ethanol resulted in dispersed nanospheres where the size was adjusted by changing the volume ratio of aqueous gelatin solution and ethanol (V Gel :V EtOH) and the gelatin concentration. Turbidity and absorbance measurements were carried out to further investigate coacervation dynamics. The cocervation system reached dynamic equilibrium according to the V Gel :V EtOH , suggesting phase separation and molecular arrangements were key. DLS results showed that reversible changes in coacervate radius could be attained by periodic heating and cooling cycles (25–60 °C). This work provides useful information for constructing gelatin-based materials using a facile coacervation method. [ABSTRACT FROM AUTHOR]

In the present work, a facile and green synthesis approach for the production of monodispersed, small-sized (2.9 ± 0.7 nm) and stable silver nanoparticles (AgNPs) using soluble soybean polysaccharide (SSPS) was reported. SSPS was used as the reducing and stabilizing agent. The obtained SSPS-stabilized AgNPs (SA) were characterized by UV–vis absorption spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy. The antimicrobial activity of the SA colloidal dispersion (SACD) was evaluated based on the growth kinetics of bacteria E. coli and S. aureus. Afterwards, the colloidal dispersion was applied as a coating material to Kraft paper. The SACD-coated Kraft paper exhibited excellent antimicrobial activity against above bacteria strains and P. aeruginosa. The effects of SACD coating on surface wettability, barrier property and microstructure of the Kraft paper were also studied. The results suggested that the SSPS-stabilized AgNPs have great potential in antibacterial applications. Unlabelled Image • A green method was developed to synthesis silver nanoparticles (AgNPs) using soluble soybean polysaccharide (SSPS) as reducing and stabilizing agent. • The synthesized AgNPs were characterized by XRD, TEM, FTIR and EDX. • The SSPS-stabilized AgNPs showed excellent antibacterial property. • The SSPS-stabilized AgNPs have great potential in antibacterial applications. [ABSTRACT FROM AUTHOR]

This work prepared high mechanical strength gelatin composite hydrogels reinforced by cellulose nanofibrils with unique beads-on-a-string morphology. In detail, cellulose nanofibrils (H-Cel) with unique beads-on-a-string morphology were obtained by acid hydrolysis followed by intensive sonication. The D-H-Cel nanofibrils were prepared through oxidizing part of the non-esterified hydroxyl groups on the H-Cel into aldehyde groups. D-H-Cel were then mixed with gelatin and D-H-Cel/Gel composite hydrogels were produced. During the mixing, a giant network structure was constructed through the Schiff-base reaction between the aldehyde groups on the surface of D-H-Cel nanofibrils and the primary amino groups on gelatin macromolecular chains. Since the cellulose nanofibrils were covalently bonded to gelatin, the stress could be efficiently transferred between the reinforcing agent and matrix, resulting in a composite hydrogel with drastically increased mechanical strength. The compressive strength of D-40H-Cel/Gel hydrogel reached 3.398 MPa. SEM images showed a highly porous three-dimensional structure in the hydrogel with regulated pore size. The crosslinking indices were measured with ninhydrin assay. The composite hydrogels could maintain their shape well in buffer solution. The present work shows that natural polymer-based composite hydrogels with extremely high mechanical strength could be obtained by reinforcing with surface modified cellulose nanofibrils with unique beads-on-a-string morphology. This work prepared high mechanical strength gelatin composite hydrogel reinforced by cellulose nanofibrils with unique beads-on-a-string morphology. Nano cellulose fibrils (H-Cel) with beads-on-a-string morphology were obtained by acid hydrolysis followed by high-power sonication. The D-H-Cel nanofibrils were prepared through oxidizing part of the hydroxyl groups on H-Cel into aldehyde groups. High strength D-H-Cel/Gel composite hydrogels were successfully prepared by covalent bonds between aldehyde groups on the surface of D-H-Cel nanofibrils and the primary amino groups of gelatin, as well as the increased contact area between the rough surface of beads-on-a-string nanofibrils and gelatin. The investigated gelatin composite hydrogels exhibited a three-dimensional porous structure and presented an improved swelling performance. The present work provides a strategy to produce the cellulose nanofibrils with unique beads-on-a-string morphology, and a high mechanical composite hydrogel based on natural polymers. Unlabelled Image [ABSTRACT FROM AUTHOR]

Efficient numerical simulation of thermo-hydraulic coupled conditions is critical for analysis and control of DH network. However, for most of meshed DH network, the flow directions of its pipelines may change, which will lead to difficulties in effective numerical calculation of the thermo-hydraulic conditions. This paper established an efficient thermo-hydraulic coupled calculation method, which utilizes the topology sorting algorithm to obtain the calculation sequence of all pipelines during numerical thermal transient calculation, according to the flow directions and flow rates of all pipelines. The flow directions and flow rates are solved by hydraulic condition calculation at each time step. The proposed method is applied to a real meshed DH network for thermal dynamic simulation. Independence analysis of hydraulic computation frequency is conducted, and convergences of the simulated temperature variations are observed when hydraulic computation frequency gets larger. Thermal dynamics of the meshed DH network are analyzed with 10-min hydraulic computation interval. Results show that the temperature decay and time delay can be up to 2.7 °C and 210 min for the simulated network. Thermal dynamic characteristics of supply temperature waves are various considering the distance from heat source, fluctuations of outdoor temperature and the variations of substation flow rate. • Topology sorting based thermo-hydraulic calculation of district heating network. • Independence analysis of hydraulic computation frequency on thermal dynamics. • Thermal transient analysis of a real meshed district heating network. • Influence of substation flow rate on district heating network thermal dynamics. [ABSTRACT FROM AUTHOR]

Low‐cost light management films that completely originate from natural polymers for biodegradable optoelectronics are a growing trend with great demand in the near future, for example, highly transparent and hazy films. Herein, a novel green method simply based on the solubility difference between cellulose and chitosan in ionic liquid is proposed to cast all‐polysaccharide transparent films with customized transmission haze. The dissolved cellulose in 1‐Allyl‐3‐methylimidazolium chloride (AmimCl) ionic liquid serves as matrix. The insoluble chitosan is deliberately dispersed in the matrix, which can maintain its original particle size due to its poor solubility in AmimCl and can significantly increase the surface roughness of the composite film and hence functions as the light scatterer. Eventually, an all‐polysaccharide composite film (Cel/CS) with high transmittance (>84.8%) and tunable haze (10–93%) is prepared using different coagulating bath and drying methods. The film is highly suitable for large‐scale continuous production and sufficient to satisfy the varying haze requirements of different applications, including flexible lighting and displays, antireflection and anti‐glare coatings, and privacy protection. [ABSTRACT FROM AUTHOR]

• An injectable aerogel was prepared with cellulose nanofiber and chitosan. • The compression strength of aerogel was improved by amide condensation. • The shape-recovering time of aerogel is less than 30 s by absorbing water. • The aerogel exhibits good antibacterial property and coagulation ability. Here an injectable antibacterial aerogel was fabricated with oxidized cellulose nanofiber and chitosan for rapid hemostasis of noncompressible hemorrhage application. Especially, cellulose nanofiber was modified with carboxyl groups by pre-oxidizing in 2,2,6,6-tetramethylpiperidine-1-oxyl combined with high pressure homogenization. Whereafter, the realized carboxyl group of cellulose nanofiber was reacted with the amidogen of chitosan to yield a strong composite aerogel with a nanofiber/nanosheet interlaced structure, which increased the compressive mechanical strength up to 75.4 kPa. In addition, the nanocellulose/chitosan composite aerogel exhibits high water absorption capacity, rapid shape recovery and good antibacterial ability (via Escherichia coli and Staphylococcus aureus). Once absorbing water, the nanocellulose5/chitosan5 compressed aerogel could rapidly recover its shape within 30 s. The in vitro coagulation ability measurement showed that the composite aerogel has a good adhesion and aggregation effect to red blood cells and platelets. Hemolysis and cytotoxicity analysis results indicated a good biocompatibility for the composite aerogel. [ABSTRACT FROM AUTHOR]

Carboxymethyl chitosan (CMCS) has good biocompatibility, biodegradability and water solubility. This work investigated a nanocellulose fibrils reinforced CMCS composite hydrogel with giant network structure and quick gelation formability. The microfibrillated cellulose (MFC) with diameter in nano scale and length in sub-micron scale was obtained through high-pressure homogenization. The hydroxyl groups on the MFC nanofibrils surface were partly oxidized into aldehyde groups. The dialdehyde MFC (DAMFC), remaining the fibril morphology and fine three-dimensional network structure, was mixed with CMCS. Due to the Schiff-base reaction between the aldehyde groups on DAMFC surface and amino groups on CMCS chains, a giant network was formed in DAMFC/CMCS. As a result, CMCS composite hydrogel could be formed in short time, although pure CMCS could not form hydrogel. In the composite, DAMFC acted as a reinforcing agent as well as a macroscopical crosslinking agent. The structure and properties of the composite hydrogels were investigated. The compression strength and the work of fracture of the hydrogel was increased dramatically as the DAMFC content increasing from 5 to 15 wt%, an increase of 330% and 338%, respectively. SEM images of the hydrogel showed a fine three-dimensional porous structure, which may provide a promising platform for tissue engineering scaffold. Hydrogels composed of natural macromolecules, having good biocompatibility, are widely used in tissue engineering. This work evaluated a dialdehyde microfibrillated cellulose (DAMFC) reinforced carboxymethyl chitosan (CMCS) composite hydrogel. Pure CMCS molecular chains entangled with each other, but cannot form hydrogel. In DAMFC/CMCS system, a giant network can be rapidly formed due to the Schiff base reaction between the aldehyde groups on DAMFC nanofibrils surface and amino groups on CMCS molecular chains. DAMFC/CMCS hydrogel presents porous structure and drastically improved mechanical strength. Unlabelled Image [ABSTRACT FROM AUTHOR]

Highlights • The bottom-supply mode and side-supply mode were studied contrastively. • The simulation results were validated by the physical experiment in the laboratory. • The indoor thermal environment, PPD and energy utilization efficiency were explored. • The bottom-supply mode provided better thermal comfort and lower energy saving. Abstract The growing energy consumption and thermal comfort of an air-conditioned room have attracted increasing public attention. As such, the performance of air-conditioning systems with two air supply modes for a simplified office room was studied by numerical simulation and physical experiment. An experimental investigation was developed in an environmental chamber to validate the simulation model. Numerical investigation was carried out subsequently for an office setting by the validated CFD model. The indoor thermal environment, human thermal comfort and energy utilization efficiency of two air supply modes were analyzed and compared in this study. The results showed that under both air supply modes, thermal stratification occurred in the model room, and the air flow velocity in the occupied zone was low. In addition, the results indicated that under 21 °C supply temperature, the air-conditioning system with bottom-supply mode provided better indoor thermal comfort of the occupied zone, but the energy consumption was higher than the side-supply mode. [ABSTRACT FROM AUTHOR]

Soluble soybean polysaccharide (SSPS)-based composite films with the addition of nano zinc oxide (nZnO, 5 wt% based on SSPS) and tea tree essential oil (TTEO, 10 wt% based on SSPS) were developed by the casting method. The effect of the combination of nZnO and TTEO on the microstructure and physical, mechanical and functional properties of SSPS films was evaluated. The results showed that the SSPS/TTEO/nZnO film exhibited enhanced water vapor barrier properties, thermal stability, water resistance, surface wettability, and total color difference, and almost completely prevented ultraviolet light transmission. The addition of TTEO and nZnO had no significant effect on the tensile strength and elongation at break of the films, but decreased the percentage of light transmittance of the films at 600 nm from 85.5 % to 10.1 %. The DPPH radical scavenging activity of the films significantly increased from 46.8 % (SSPS) to 67.7 % (SSPS/TTEO/nZnO) due to the presence of TTEO. Scanning electron microscopy analysis indicated that nZnO and TTEO were evenly dispersed in the SSPS matrix. The synergistic effect of nZnO and TTEO endowed the SSPS film with excellent antibacterial activity against E. coli and S. aureus , suggesting that the SSPS/TTEO/nZnO film could be a promising material for active packaging applications. [Display omitted] • Soluble soybean polysaccharide (SSPS)/tea tree essential oil (TTEO)/nano zinc oxide (nZnO) composite film was fabricated. • nZnO and TTEO enhanced barrier and antioxidant properties of the SSPS films. • The synergistic effect of nZnO and TTEO endowed the SSPS film with excellent antibacterial activity. • The composite film has a high potential for active packaging application. [ABSTRACT FROM AUTHOR]

Hydraulic performance of district heating (DH) network is the key to energy reduction of DH system. Efficient hydraulic operation strategy requires precise values of the hydraulic resistances of pipelines. In this paper, a hydraulic resistance identification method was developed. With this method, precise hydraulic resistances of all the pipelines in the DH network can be obtained based on the pressure and flow rate values observed at the heating substations under different hydraulic conditions. An optimal pressure control strategy of DH network was established based on the identified hydraulic resistances for energy reduction of the pumping systems. The feasibility and effectiveness of the hydraulic resistance identification method were analyzed with the well-developed hydraulic simulation technique of district heating network realized in Matlab environment. Hydraulic performances of the optimal pressure control (OPC) strategy were compared with the traditional constant pressure difference control (CPDC) strategy. Results show that the pumping energy of DH system under the control of CPDC can be reduced by 14.6% compared with OPC during the heating period. [ABSTRACT FROM AUTHOR]

In this paper, a solar air collector with slit-perforated corrugated plate is put forward, which is a combination of transpired solar air collector and corrugated packing solar air collector. The slit-perforated corrugated plate can enlarge the heat collection area and reinforce the jet impingement largely. The mathematical model is developed to predict thermal performance of the collector. Simulation results of temperature distribution in the collector are verified by the experimental data with the average bias of 4.8%. The local resistance coefficient of the collector is obtained though experimental results. The effects of key parameters on thermal efficiency are analyzed. It can be found that the height of absorber plate has the largest effect on thermal performance among structure parameters. And when air velocity in the collector increases to 1.14 m/s, effective efficiency can reach the peak, 67.83%. Compared with other transpired solar air collectors, the present solar air collector has better thermal performance and lower resistance. Case study shows that the application of the present solar air collector can produce 820.7 MJ in the heating season, which can save 43.1 kg standard coal and reduce 102.1 kg carbon dioxide emission. Hence, there is application potential for space heating in the cold region. [ABSTRACT FROM AUTHOR]

Activated carbon-entrapped microfibrilated cellulose (AC/C) films were successfully fabricated by self-assembly of cellulose microfibrils via a simple and environmentally friendly method. The structures and properties of films were characterized by scanning election microscope (SEM) as well as density, turbidity, and mechanical analyses. Cationic brilliant red 5GN (CBR) was selected as a model dye, and the adsorption of CBR in aqueous solution by AC/C films was evaluated. Adsorption kinetics was described by the pseudo-second-order model, and the absorption behaviors were in agreement with a Langmuir isotherm. Thermodynamic analyses indicated that CBR adsorption onto AC/C film was favorable. The adsorption–desorption cycle of AC/C films was repeated three times without significant loss of adsorption capacity. Moreover, AC particles in films showed high stability during adsorption. This work proposes a novel utilization of bulk forms of adsorption particles within cellulose networks to achieve better adsorption applications in water treatment. [ABSTRACT FROM AUTHOR]

Predicting the thermal transients of district heating (DH) network is the key to simulation analysis and operation optimization of DH system. Numerical methods can provide accurate prediction and sufficient information of thermal transients. But the high computation burden restricts the application of numerical methods, especially when applied to operation optimization of large DH networks. This dilemma can be relieved by suitably increasing the scales of time and spatial steps, but do not obviously affect the precision of the numerical models. However, there are few researches concerning such topics. In this paper, the optimal scales of time and spatial steps of a newly proposed implicit upwind model and the characteristic line model were studied for fast and accurate calculation. Results show that both models can ensure the prediction errors of the pipeline outlet temperature within ±0.5 °C. For characteristic line model, the recommended time step and spatial step are 60 s and 170 m < Δ x < 520 m. And for implicit upwind method, the recommended time step and spatial step are 20 s and 30 m. Besides, the implicit upwind model is unconditionally stable and provides more information on temperature distribution along the pipeline, especially when small and fast propagation occurs. [ABSTRACT FROM AUTHOR]

Heat output and uniformity of surface temperature distribution are primarily concerned by designers and users of radiant floor heating. The testing approach, testing conditions and calculation of the heat output at each stage of program are different among the test standards. In this paper, a mathematical model to calculate surface temperature and heat output of radiant floor heating system was proposed. Measured data from experiments was used to validate the proposed model. Based on this simulation model, four current test standards in China, Europe, America and Japan were simulated. The simulation results show that the heat output of the same sample is different under the four test standards. Meanwhile, simulations were carried out at various non-heating surface temperatures. The results indicate that the non-heating surface temperature has a significant impact on the heat output of the radiant floor. The differences in the simulations of heating capacity vary from 2% to 7%. Hence, a parameter, the temperature difference between average water temperature of test sample and area weighted average temperature of non-heating surfaces, is introduced to revise the heat output characteristic equation based on the Chinese test standard. [ABSTRACT FROM AUTHOR]

Since the heating substation plays a key role in transferring the thermal energy from the primary network to the secondary network and controlling the heat output of district heating system to meet the thermal load, high operation performance of heating substation is essential for energy conservation, cost saving and emission reduction. The dynamic operation stability of heating substation is a very important dynamic characteristic of heating substation and largely affects the operation efficiency of district heating system. The operation instability of heating substation mainly manifest as flow rate and pressure oscillations, which will deteriorate the network hydraulic condition, break the network thermal balance, reduce the consumer comfort and increase the energy cost of the pumping system. Since heating substations will easily operate unstably under some conditions, this paper presents a theoretical method to analyze the stability and retune the feedback controller for operation stability of heating substation. Mathematical model of the plate heat exchanger was established and the feedback control theory was adopted to study the operation stability of heating substation. Based on the mathematical model and feedback control theory, a stability criterion was proposed for analyzing the operation stability of district heating substation effectively. The dynamic model of plate heat exchanger was validated with measured data. Simulation results show that controller tuned at certain operating condition can’t ensure operation stability of heating substation, when operating condition varies in large range. The stability analysis method proposed in this paper can be applied to analyzing the operation stability and tuning the controller of heating substation to enhance the operation stability. [ABSTRACT FROM AUTHOR]

The thermal performance of a novel solar air collector with metal corrugated packing in the buildings of cold regions is studied in this paper. Mathematical models are developed to investigate the thermal performance of the collector and the results are verified by experiments. The hydraulic analysis is conducted experimentally to study the pressure drops of the air flows in the corrugated packing. Effects of the structural and operating parameters, such as the collector width, height, specific surface area and solar radiation intensity, ambient air temperature, air inlet temperature and velocity are studied to optimize the thermal performance of the collector. Comparisons are conducted among the metal corrugated packing solar air collector, the unglazed transpired solar collector, the glazed transpired solar collector and the packed bed solar collector with iron chips. The results indicate that the metal corrugated packing solar air collector is more appropriate to be used in the rural buildings of cold regions for its advantages of large heat transfer area, high heat transfer coefficient and good economic performance. [ABSTRACT FROM AUTHOR]

According to the annual air quality report released by the Ministry of Environmental Protection of China, the cities that requiring heating reported an average of 168.3 days that could not reach the air quality standard, which was 59.8% higher than warm cities that did not require heating in 2014. Coal-fired energy conversion for building space heating can generate a large amount of haze pollutions during the winter. More seriously, the year-by-year data of district heating capacity increases with an average growth rate of 5.59% published in the China Statistical Yearbook, which means more and more heating associated pollutants will emit into the atmosphere and result in the worse and worse environment quality predictability in the further without taking any effective measure. In this context, considering the factors of energy, environment and human health simultaneously, this paper aimed to develop an air quality index (AQI) associated with energy conversion for building space heating model to guide the energy-saving measures on heating. Principal component analysis and grey relation projection evaluation theory approaches were used to preprocess the historical AQI data. Moreover, a simplified two-dimensionality heating capacity model based on EnergyPlus simulation results was introduced to expand the application range of the AQI-Heating (A-H) model. The A-H model included three components, which were the direct pollutant emission, regenerated pollutant emission and urban self-purifying capacity. Four pollutants related input coefficients including the direct emission factor A , the urban maximum purifying capacity a , the attenuation coefficient b and the regenerated coefficient ξ were solved by homemade code based on Matlab software according to a 10-year observed data (2003–2015). The performance of A-H model was compared with the actual values (data from 2015 to 2016) and the results of conventional linear and nonlinear regression techniques, in terms of the index of mean absolute error ( MAE ), mean absolute percentage error ( MAPE ), root-mean-squared error ( RMSE ) and index of agreement ( IA ). All performance metrics proved that the A-H model was accurate enough (e.g. IA = 0.983) to analyze the relationship between the AQI and the energy conversion for building space heating. [ABSTRACT FROM AUTHOR]

Tannin-immobilized cellulose (CT) hydrogels were successfully fabricated by homogeneous immobilization and crosslinking reaction via a simple method. The structures and properties of hydrogels were characterized by SEM and mechanical test. Methlyene Blue (MB) was selected as a cationic dye model, and the adsorption ability of CT hydrogel was evaluated. Tannins immobilized acted as adsorbent sites which combined MB by electrostatic attraction, resulting in the attractive adsorption ability of CT hydrogel. Adsorption kinetics could be better described by the pseudo-second-order model, and the absorption behaviors were in agreement with a Langmuir isotherm. The adsorption-desorption cycle of CT hydrogel was repeated six times without significant loss of adsorption capacity. In this work, both tannin immobilization and hydrogel formation were achieved simultaneously by a facile homogeneous reaction, providing a new pathway to fabricate tannin-immobilized materials for water treatment. [ABSTRACT FROM AUTHOR]

The PTC (parabolic trough solar collector) is widely used for space heating, heat-driven refrigeration, solar power, etc. The concentrated solar radiation is the only energy source for a PTC, thus its optical performance significantly affects the collector efficiency. In this study, four different optical models were constructed, validated and compared in detail. On this basis, a novel coupled method was presented by combining advantages of these models, which was suited to carry out a mass of optical simulations of collectors with different geometrical parameters rapidly and accurately. Based on these simulation results, the optimal configuration of a collector with highest efficiency can be determined. Thus, this method was useful for collector optimization and design. In the four models, MCM (Monte Carlo Method) and FVM (Finite Volume Method) were used to initialize photons distribution, as well as CPEM (Change Photon Energy Method) and MCM were adopted to describe the process of reflecting, transmitting and absorbing. For simulating reflection, transmission and absorption, CPEM was more efficient than MCM, so it was utilized in the coupled method. For photons distribution initialization, FVM saved running time and computation effort, whereas it needed suitable grid configuration. MCM only required a total number of rays for simulation, whereas it needed higher computing cost and its results fluctuated in multiple runs. In the novel coupled method, the grid configuration for FVM was optimized according to the “true values” from MCM of collectors with the maximum geometry difference. Following this, the initialization of photons distribution of collectors with different geometries were conducted with FVM. To demonstrate this coupled model in real practice, performance analysis of a kind of cavity receiver for PTCs was carried out. The judgment of collectors with maximum geometry difference were worth investigating further in the future work. [ABSTRACT FROM AUTHOR]

Operational optimization is the key to energy reduction of the district heating (DH) system. Poor hydraulic performances of the DH network will largely increase the energy consumption. However, for most meshed DH networks with multiple heat sources, the optimal hydraulic conditions are usually not achieved. In this paper, the hydraulic performance optimization problem of meshed DH network with multiple heat sources was proposed. In order to solve the problem, the General Reduced Gradient (GRG) algorithm was adopted to minimize the total pump power through optimizing the pump frequencies and substation valve openings of the DH network. The hydraulic performances of the GRG algorithm based optimal control (OC) strategy were compared with the traditional constant pressure difference control (CPDC) and the constant speed control (CSC) strategies. Results shows that in comparison with the CPDC and CSC strategy, the total pump power can be reduced by 20% and 65% respectively, when applying the OC strategy. And the hydraulic intersection point of the DH network was changeable to reallocate the serving areas of heat sources and optimize the total pump power. Besides, increasing the pump efficiency without considering the hydraulic constraints of the DH network may not lead to optimal conditions. [ABSTRACT FROM AUTHOR]