摘要：
The mesoporous carbons with abundant Fe-Co sites were prepared through one-step carbonization of a MOF materials (ZIF-67) with sodium iron ethylenediaminetetraacetic acid [NaFe(III)EDTA], which can facilitate the nucleation and growth of highly dispersed palladium active sites. The robust synergistic interaction between Pd and FeCo metal with moderate work functions is responsible for the enhanced catalytic activity. Interfacing Pd nano-particles with FeCo sites has been demonstrated for the first time to boost the heterogeneous catalysis of hydrogen production from formic acid, affording the high turnover frequency (TOF) value of 1288 h- 1 at 303 K. The Pd-Fe-Co sites also help to achieve outstanding catalysis performance of in situ hydrogenating phenol. The 91.1 % of the conversion of phenol and 92.7 % of the selectivity of cyclohexanone has been obtained with formic acid as H-donor.
作者机构：
[Long, Yun; Bao, Yude] Guangdong Power Grid Co Ltd, Guangzhou Power Supply Bur, Guangzhou 510260, Peoples R China.;[Zeng, Linjun] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha, Peoples R China.
通讯机构：
[Zeng, LJ ] C;Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha, Peoples R China.
关键词：
power monitoring system;cloud-edge-device collaboration;large-scale digital substation;edge computing;intelligent patrol;intelligent operation;decision fusion
摘要：
With the continuous promotion of digital transformation in the field of power transformation, the diversification of application scenarios, and the scale of pilot construction, the real-time, concurrency, and security requirements for data fusion and application support of the power monitoring system, management information system, and other business platforms are getting higher and higher, and this paper puts forward a high concurrency and availability "cloud-side-end collaboration" based on edge computing. This paper proposes a high concurrency and availability "cloud, edge and end collaboration" architecture based on edge computing for substation operation support systems. First, this paper summarizes the development status of domestic substation operation support systems and analyzes the advantages and disadvantages of various technical architectures. Then, a "cloud-side-end cooperative" substation operation support system architecture with "high real-time, high concurrency, high security and high stability" is proposed, which focuses on remote inspection, remote operation, and remote safety control of substation businesses from the perspective of engineering applications. It realizes transparent monitoring of equipment operation, unified management of operation data, and integration of production command and decision-making; solves the problems of dispersed coexistence of multiple systems for dispatching, monitoring, analysis, management, and other businesses, switching between multiple systems, and insufficient real-time and stability of the system; and controls the risks of the grid, reduces the potential safety hazards, and solves the contradiction between the continuous growth of the grid equipment and the shortage of production personnel. The results of engineering application examples show that the proposed architecture compared with the existing system architecture has greater advantages and can meet the requirements of large-scale access to the substation, with feasible popularization and application.
期刊：
Journal of Alloys and Compounds,2024年976:173160 ISSN：0925-8388
通讯作者：
Ouyang, LZ;Zhang, JR
作者机构：
[Qin, Chenglei; Zhong, Hao; Wang, Hui; Ouyang, Liuzhang; Liu, Jiangwen] South China Univ Technol, Sch Mat Sci & Engn, Guangzhou 510641, Peoples R China.;[Qin, Chenglei; Zhong, Hao; Wang, Hui; Ouyang, Liuzhang; Liu, Jiangwen] South China Univ Technol, Key Lab Adv Energy Storage Mat Guangdong Prov, Guangzhou 510641, Peoples R China.;[Zhong, Hao] Guangzhou High Tech Zone Inst Energy Technol, Guangzhou 510000, Peoples R China.;[Chen, Kang] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Key Lab Efficient & Clean Energy Utilizat, Changsha 410111, Peoples R China.;[Lang, Chengguang] Sun Yat sen Univ Shenzhen, Sch Adv Energy, Shenzhen 518107, Peoples R China.
通讯机构：
[Zhang, JR ] L;[Ouyang, LZ ] S;South China Univ Technol, Sch Mat Sci & Engn, Guangzhou 510641, Peoples R China.;South China Univ Technol, Key Lab Adv Energy Storage Mat Guangdong Prov, Guangzhou 510641, Peoples R China.;Lishui Univ, Dept Chem, Lishui 323000, Peoples R China.
摘要：
Onsite hydrogen generation by sodium borohydride hydrolysis resolves hydrogen energy supply system challenges. However, the spent-NaBH4 regeneration is still a problem in the closed loop of this irreversible reaction. As the by-product is the key to the problem, NaB(OH)4 is regarded as not the boron source but the hydrogen source of NaBH4 regeneration. Therefore, in this study, inexpensive Al metal and NaB(OH)4 are ball milled under argon to regenerate NaBH4 without additional hydrogen input. However, the ball-milling reaction is hindered by the flexible Al and impact oxide layer, and the NaBH4 yield is only approximately 22 %. Therefore, a brittle intermetallic compound Mg2Al3 is reacted with NaB(OH)4 by ball milling, achieving a NaBH4 yield of over 42 %. The mechanism study shows that the brittleness of the raw material plays an important role in promoting the ball-milling reaction. This study achieves NaBH4 regeneration using only Al as the reducing agent and provides a promising method to promote the mechanochemical regeneration of NaBH4.
摘要：
Fatigue performances of critical structures are strongly affected by the microstructural (e.g. grain, defect, inclusion, etc.) size effect, and it is thus important to quantify their detrimental effect. In this work, a numerical procedure is constructed to quantify the influence of microstructure on the mechanical and fatigue behaviors of Ni-based superalloy GH4169. Specifically, by combining sub modelling approach with crystal plasticity constitutive model, a dual-scale modelling approach is developed for studying grain-level mechanical behavior of Ni-based superalloy GH4169 notched components. In addition, the dislocation-based Tanaka-Mura-Wu model is applied for fatigue crack initiation life prediction. The Paris law is then utilized for fatigue crack propagation analysis based on the simulated short crack. To study the microstructural size effect on fatigue crack initiation and propagation behaviors, sub-models containing various grain orientation, grain size, defect size/shape are built and analysed. Finally, a series of fatigue tests on notched specimens of Ni-based superalloy GH4169 were carried out for method validation. Results indicate that the established dual-scale modelling approach and fatigue life prediction framework yields good agreement with experimental results.
关键词：
PV direct driven air conditioner (PVAC);Zero energy buildings;Load flexibility;Building design
摘要：
The energy matching of PV driven air conditioners is influenced by building load demand and PV generation. Merely increasing energy performance of building or PV capacity separately may improve the energy balance on a large time resolution, the real-time energy mismatching problem is still serious. In this study, a coordinated optimization method of PV capacity, building design, and load flexibility is proposed for improving the real-time energy matching of PVAC system. Then, a methodology integrating data mining method (XG Boost) and parametric simulation was developed to identify the determinant parameters of PV system and building design, exploring feature importance and correlations. The results of XG Boost indicate that the PV capacity, shape factor, and SHGC are the most critical factors. Finally, based on the optimized building design, the PCM layer was applied to improve the real time energy matching. To achieve a goal of 90 % ZEP, the PCM capacity can be decreased by 50.4 % and 62.8 % in Guangzhou and Shanghai in the optimized building. Moreover, the PV capacity can be reduced by 23 % in Guangzhou. The findings of this study provide practical guidance for designing PVAC system coupling with building design and energy storage devices.
作者机构：
[Li, Chuanchang; Li, Yaxi; Li, Mu; Xie, Baoshan; Peng, Meicheng; Li, CC] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Key Lab Renewable Energy Elect Technol Hunan Prov, Changsha 410114, Peoples R China.
通讯机构：
[Li, CC ] C;Changsha Univ Sci & Technol, Sch Energy & Power Engn, Key Lab Renewable Energy Elect Technol Hunan Prov, Changsha 410114, Peoples R China.
关键词：
Refrigerated transportation;Sodium carbonate decahydrate;Phase change materials;Cold energy storage
摘要：
The technology of cold energy storage with phase change materials (PCMs) can effectively reduce carbon emissions compared with the traditional refrigerated transportation mode, so it has attracted increasing attention. Using sodium carbonate decahydrate (SCD) as the cold energy carrier, and improving its performance through additives, the SCD composite PCM for refrigerated transportation of fresh fruits was successfully prepared. Its melting temperature was 9.3 degrees C, melting latent heat was 90.7 J/g, and the degree of supercooling was 5 degrees C. The phase and microstructure of the prepared PCMs were investigated by XRD and SEM respectively, which proved the materials had good compatibility. The application experiment showed that the cold storage plate filled with prepared PCM could storage cold energy at an ambient temperature of 2 degrees C, and the prepared PCM could significantly prolong the preservation time of fruits.
摘要：
Corrosion caused by salt-spray and fatigue failure resulting from cyclic sea wave and strong storm are common degradation problem in offshore structural steels, and their interaction would accelerate service failure of these steels. In this work, therefore, FeCoNiCrMn high-entropy alloy (HEA) coatings were first prepared on 321 steels to simultaneously improve their corrosion and fatigue resistance. Then the pre-corrosion in salt-spray environment and subsequent high-cycle fatigue (HCF) tests were conducted on both coated and uncoated steel. The same HCF tests were also performed on the uncorroded steel specimens to reveal the influence of pre-corrosion on their fatigue resistance. The results showed that the corrosion and fatigue resistance of coated steel were both improved, which should be attributed to the higher strength, dislocation motivity and formation rate of corrosion film of the HEA coating. Moreover, pre-corrosion would decrease the mechanical properties and depth of the HEA coating, leading to significant damage to the fatigue resistance of coated steel. However, after pre-corrosion, the fatigue life of uncoated and coated steel was decreased by 18.2 %–38.8 % and 34.4 %–42.6 % at different stress amplitudes, respectively, showing the significant protective effect of HEA coatings against the pre-corrosion damage to fatigue life of offshore 321 steel.
作者机构：
[Li, Chuanchang; Ma, Huan; Xie, Baoshan; Chen, Jian; Li, CC] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Key Lab Renewable Energy Elect Technol Hunan Prov, Changsha 410114, Peoples R China.;[Li, Chuanchang; Xie, Baoshan; Chen, Jian; Li, CC] Changsha Univ Sci & Technol, State Key Lab Disaster Prevent & Reduct Power Grid, Changsha 410114, Peoples R China.
通讯机构：
[Li, CC ] C;Changsha Univ Sci & Technol, Sch Energy & Power Engn, Key Lab Renewable Energy Elect Technol Hunan Prov, Changsha 410114, Peoples R China.;Changsha Univ Sci & Technol, State Key Lab Disaster Prevent & Reduct Power Grid, Changsha 410114, Peoples R China.
关键词：
thermal energy storage;phase change material;stone coal;vanadium extraction;secondary utilization
摘要：
Phase change materials (PCMs) can be incorporated with low-cost minerals to synthesize composites for thermal energy storage in building applications. Stone coal (SC) after vanadium extraction treatment shows potential for secondary utilization in composite preparation. We prepared SC-based composite PCMs with SC as a matrix, stearic acid (SA) as a PCM, and expanded graphite (EG) as an additive. The combined roasting and acid leaching treatment of raw SC was conducted to understand the effect of vanadium extraction on promoting loading capacity. Results showed that the combined treatment of roasting at 900 degrees C and leaching increased the SC loading of the composite by 6.2% by improving the specific surface area. The loading capacity and thermal conductivity of the composite obviously increased by 127% and 48.19%, respectively, due to the contribution of 3wt% EG. These data were supported by the high load of 66.69% and thermal conductivity of 0.59 W center dot m-1 center dot K-1 of the designed composite. The obtained composite exhibited a phase change temperature of 52.17 degrees C, melting latent heat of 121.5 J center dot g-1, and good chemical compatibility. The SC-based composite has prospects in building applications exploiting the secondary utilization of minerals.
摘要：
In this work, APBO and its typical organic matter (HAc, Phenol, Guaiacol) were used to pretreat wheat straw separately, and CFP characteristics of wheat straw before and after the pretreatment were investigated. Washing with four different solutions removed more than 95% of K(+ )and over 86% removal of Na+; the removal effect of APBO on Ca2+ and Mg2+ is more evident with more than 84%. Washing reduced AAEMs, thereby reducing acids and ketones and increasing sugars in the bio-oil. TGA demonstrated that different washing significantly increased wheat straw's maximum weight loss rate and overall weight loss rate. After the subsequent addition of HZSM-5 catalyzed pyrolysis, the level of oxygen-containing compounds in bio-oil was significantly reduced and the aromatic hydrocarbon level increased from 2.19% (R) to 14.89% (CR), 31.28% (APBO-CR), 25.9% (HAc-CR), 24.74% (Phenol-CR), 15.81% (Guaiacol-CR), and the highest selectivity was 54.57% for BTX (APBO-CR). The combined APBO washing and HZSM-5 is a potential technology for upgrading biomass and the liquid products of pyrolysis because it can effectively raise bio-oil quality.
期刊：
Journal of Materials Chemistry A,2024年12(1):277-285 ISSN：2050-7488
通讯作者：
Yang, J;Cao, PH
作者机构：
[Yang, J; Tang, Jingjing; Yang, Juan; Meng, Qi; Zhang, Guilin; Bai, Qixian] Cent South Univ, Sch Met & Environm, Changsha 410083, Peoples R China.;[Liu, Weiping; Lin, Wenjun; Yi, Pengfei] Zhuzhou Smelter Grp Co Ltd, Zhuzhou 412000, Peoples R China.;[Cao, Penghui] Changsha Univ Sci & Technol, Coll Energy & Power Engn, Changsha 410114, Peoples R China.
通讯机构：
[Yang, J ; Cao, PH ] C;Cent South Univ, Sch Met & Environm, Changsha 410083, Peoples R China.;Changsha Univ Sci & Technol, Coll Energy & Power Engn, Changsha 410114, Peoples R China.
摘要：
Aqueous zinc-ion batteries (AZIBs) are considered to be a green and safe energy storage system. However, electrolyte leakage, zinc dendrite growth and side reactions are still barriers to their practical application. A quasi-solid sodium alginate gel electrolyte (GE) was designed to alleviate these pain points. To further stabilize the water molecules in this GE and extend its application to subzero temperatures, a disaccharide called trehalose (TreH) was introduced as a multifunctional additive. The rational introduction of TreH notably improved the strength (186.6 kPa) of the sodium alginate GE while retaining a high ionic conductivity (22.4 mS cm-1) at 25 degrees C. The zinc-polyaniline full battery assembled with this composite GE exhibited a capacity retention of 70.4% after 500 cycles at 25 degrees C, and still delivered a reversible capacity of 120.6 mA h g-1 at -20 degrees C. These results show that the sodium alginate GE with trehalose as an additive has great potential for development in AZIBs. Sodium alginate was selected as a matrix and trehalose was employed as an additive to form a hydrogel electrolyte for Zn-ion batteries applied at low temperatures.
作者机构：
[Hu, Zhiming; Chen, Wei; Zhou, Libo; Niu, Yan; Ren, Yanjie; Li, Cong; Qiu, Wei; Chen, Jian; Peng, Zeai; Zhou, LB; Liu, Jiaqing] Changsha Univ Sci & Technol, Inst Energy & Power Engn, Changsha 410114, Peoples R China.;[Zhou, Libo; Zhou, LB] Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;[Zhou, Libo; Zhou, LB] Zhuzhou Smelter Grp Co Ltd, Zhuzhou 412000, Peoples R China.
通讯机构：
[Zhou, LB ] C;Changsha Univ Sci & Technol, Inst Energy & Power Engn, Changsha 410114, Peoples R China.;Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;Zhuzhou Smelter Grp Co Ltd, Zhuzhou 412000, Peoples R China.
关键词：
grain morphology;Inconel 625 alloy;laser powder bed fusion;mechanical property
摘要：
The controlling strategies of grain morphology and mechanical properties of Inconel 625 alloy by laser powder bed fusion are investigated, and beyond that, the effects of phase composition, grain morphology, and crystallographic texture on mechanical properties are also studied. The phase evolution is insensitive to the scanning strategies, and all of the samples are composed of gamma-Ni phase. The (001) texture orientation tends to increase with the scanning rotation angle, and the sample IV fabricated by scanning strategies of 90 degrees shows the highest (001) texture. Different grain morphologies can be tailored by controlling the direction of heat flow between continuous layers via changing scanning strategies. The proportion of large elongated columnar crystals gradually decreases, while the proportion of the equiaxed grains gradually increases as the scanning strategies change from 0 degrees -> 90 -> 67 degrees -> 45 degrees. The rotation angle increases from 0 degrees to 45 degrees, and the ultimate tensile strength and yield strength increase from 1267 +/- 12 to 1304 +/- 5 MPa and 760 +/- 10 to 801 +/- 5 MPa, respectively, which is attributed to the different stress states presented in the columnar crystals and the equiaxed crystals. The Inconel 625 alloy is manufactured by laser powder bed fusion (LPBF) with four scanning strategies of 0 degrees, 45 degrees, 67 degrees, and 90 degrees, under the condition that other parameters are consistent. The effects of different scanning strategies on the grain morphology and mechanical properties of LPBF-fabricated Inconel 625 alloy are systematically investigated.image (c) 2024 WILEY-VCH GmbH
期刊：
Renewable & Sustainable Energy Reviews,2024年189:114005 ISSN：1364-0321
通讯作者：
Kapsalis, V;Karamanis, D
作者机构：
[Kapsalis, Vasileios] Natl Tech Univ Athens, Sch Mech Engn, Sect Ind Management & Operat Res, Athens, Greece.;[Maduta, Carmen] European Commiss, Joint Res Ctr JRC, Ispra, VA, Italy.;[Skandalos, Nikolaos] Czech Tech Univ, Univ Ctr Energy Efficient Bldg,1024 Trinecka St, Bustehrad 27343, Czech Republic.;[Wang, Meng] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha 410114, Hunan, Peoples R China.;[Raj, Uday; Bhuvad, Sushant Suresh] Indian Inst Technol Bhilai, Dept Mech Engn, Bhilai 492015, Chhattisgarh, India.
通讯机构：
[Kapsalis, V ] N;[Karamanis, D ] U;Natl Tech Univ Athens, Sch Mech Engn, Sect Ind Management & Operat Res, Athens, Greece.;Univ Patras, Dept Environm Engn, Agrinion 30100, Greece.
关键词：
Solar energy;Photovoltaics;Building-integrated photovoltaics;Rooftop PV;Zero energy buildings;Urban decarbonisation
摘要：
In support of the clean energy transition, rooftop photovoltaics (RTPV) deployment has been globally advocated, enabling citizens as energy prosumers within their localised building environment. However, the effectiveness of RTPV implementation is influenced by diverse bioclimatic conditions. Here, we provide a critical climate-related RTPV characterisation across the globe, consisting of a comprehensive assessment of RTPV performance, taking into account global horizontal irradiation (GHI) and local environmental parameters, including space conditioning requirements in different climatic zones. Additionally, we examine the technological advancements aimed at improving efficiency in RTPV systems.
Within a meta-data analysis, we find that the RTPV systems offer various advantages in terms of building overall energy performance, particularly in moderate and warm climates. We observe that typical or increased insulation values can offset the RTPV effect in uninsulated roofs. This is essential in regions with cold climates and helps to mitigate increased heating requirements during winters or higher cooling demands during summer nights. A relationship between the ratio of building space coverage to PV surface and GHI is proposed for low-energy buildings to calculate the space requirements for achieving net zero buildings, globally. Moreover, in hot climates, cooling the RTPV surfaces can enhance efficiency by up to 20 % and increase power output by up to 15 %. By advancing RTPV efficiency to 30 % with emerging technologies, the decarbonisation of high-rise buildings can be facilitated, alongside energy efficiency and RTPV implementation measures. Striking a balance between thermal insulation needs, we conclude that RTPV offers wide benefits across different climatic conditions.
摘要：
This work investigates the electrochemical behavior and discharge performance of Mg-3Al-0.4Ca-0.7Mn alloys with three extrusion ratios (ER) of 10, 16 and 25 as anodes for Mg -air batteries. The results show that the ER16 sample has the lowest corrosion current density and the highest corrosion resistance. The corrosion performance of the ER25 sample is slightly reduced due to the excessive discontinuous second phase leading to elevated selfcorrosion rate. The alloy exhibits higher discharge voltage and stable discharge process with increasing extrusion ratio. Increasing the extrusion ratio has a homogeneous microstructure, the increase in the area fraction of nonbasal oriented grains is conducive to the homogeneous dissolution of the anode and the inhibition of the "chunk effect". The ER25 sample showed the highest anode efficiency, specific capacity and energy density of 55.73 %, 1306.67 mA h g-1 and 1635.947 mW h g-1 at 20 mA cm -2, respectively.
摘要：
Foaming pretreatment has been proven effective in promoting sludge drying, however, the variation in sludge properties significantly influences the foaming efficiency. Inspired by foam stabilizer of solid particles, Camellia oleifera shells (COS) was screened out from various biomasses as an additive incorporated with the CaO for promoting the sludge foaming. For the introduction of COS, this study analyzed the drying behaviors of foamed sludge, quantified the surface cracks information, characterized the combustion performance, and evaluated the energy consumption. The results indicated that 46.72-50.10% of time could be saved in foaming the sludge to 0.70g/mL by addition of 3.0wt% COS. Compared with the original sludge (OS), the 0.70g/mL foamed sludge saved 47.43% of time for sludge drying at 80°C, and this value further increased to 53.14% with 3.0wt% COS addition. Combining the multifractal spectra and drying kinetics analysis, the foaming promoted the formation of complex surface cracks in the warm-up period, while COS further improved the complexity of cracks in the constant rate period, and the shrinkage of isolated sludge blocks in the falling rate period, thus enhanced the moisture diffusion and heat transfer. Furthermore, the appropriate porous structure and additional volatile matters promoted the combustion performance. The 0.90g/mL foamed sludge with COS presented the lowest activation energy of 180.362kJ/mol in combustion. Overall, compared with OS, the 0.70g/mL foamed sludge with COS saved 40.65% energy consumption during the foaming, drying and combustion processes, providing an energy-efficient solution for the sludge treatment and disposal.
期刊：
International Journal of Reasoning-based Intelligent Systems,2024年15(3-4):297-303 ISSN：1755-0556
作者机构：
[Quan Gan] Department of Architecture, Henan Technical College of Construction, Henan 450064, China;[Yucai Zhou] School of Energy and Power, Changsha University of Science and Technology, Changsha 410076, China
关键词：
naive Bayes;2D art image;colour distortion;histogram equalisation;multi-scale retinal algorithm
摘要：
Aiming at the problems of low correction accuracy and long correction time in the traditional two-dimensional art image colour distortion correction method, a two-dimensional art image colour distortion correction method based on naive Bayes is proposed. Through the RGB image sensor, the brightness pixels are relatively evenly distributed on the histogram through the conversion of four links: world coordinate system, camera coordinate system, photosensitive device coordinate system and pixel coordinate system. Binarisation is carried out based on naive Bayes. According to the binarisation results, the salient regions of two-dimensional art images are extracted. Based on the obtained key regions, the multi-scale retinal algorithm with colour restoration is used to correct the colour distortion of two-dimensional art images. The experimental results show that the proposed method has the highest accuracy and the shortest correction time.
期刊：
Journal of Energy Storage,2024年85:111124 ISSN：2352-152X
通讯作者：
Ye Tan<&wdkj&>Ju-Lan Zeng
作者机构：
[Ye Tan; You-Tong Zhu; Rong Chen; Sheng-Ci Cui; Qi Wang; Lin-Ping Yu; Ju-Lan Zeng] Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, Hunan Provincial Key Laboratory of Cytochemistry, School of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, PR China;Hunan Xiangli Salt Chemical Co, Ltd, Jinshi 415400, PR China;[Chuan-Chang Li] School of Energy and Power Engineering, Changsha University of Science and Technology, Changsha 410114, PR China;[Ping Hu] Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, Hunan Provincial Key Laboratory of Cytochemistry, School of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, PR China<&wdkj&>Hunan Xiangli Salt Chemical Co, Ltd, Jinshi 415400, PR China
通讯机构：
[Ye Tan; Ju-Lan Zeng] H;Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, Hunan Provincial Key Laboratory of Cytochemistry, School of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, PR China
摘要：
Microencapsulating phase change materials (PCMs) with CaF2 as shell could obtain not only novel microencapsulated PCMs (MPCMs) but also potential luminescence materials with self-thermal regulation property. Prior to the preparation of good luminescent MPCMs with doped CaF2 as shell, the formation mechanism of the MPCMs should be well understood. In this work, n-octadecane (ODE) was selected as core to prepare CaF2 MPCMs and the formation mechanism was comprehensively investigated. The results revealed that the concentrations of the Ca2+ and the F− in the solution, which could be adjusted by the coordination equilibrium of Ca-citrate complex and the hydrolysis balance of NaBF4, played key roles in formation of the MPCMs. Moreover, the formation of the MPCMs was composed of five periods, including: formation of emulsion; formation of Ca-citrate intermediate microcapsules; induction of CaF2 shell; growth and aggregation of CaF2 shell and overgrowth of CaF2. Meanwhile, the results also revealed that prolonging the overgrowth period of CaF2 had significant effects on the morphology and properties of the prepared MPCMs. In addition, with the increase of the reaction temperature, the nucleation, growth and aggregation of CaF2 crystals could be accelerated, and the formation and growth periods of the CaF2 shell were shortened. This work is not only significant for the preparation and optimization of MPCMs with CaF2 as shell, but also can guide and promote the development of luminescent MPCMs.
摘要：
Electromagnetic powder compaction technology is an effective method for producing high density and strength parts. In this work, the influence of discharge energy on the electromagnetic compaction characteristics of copper powders with same compression amount was studied through experiment investigation and numerical simulation. The finite element simulation, micro morphology observation, and compressive strength testing were conducted. Results showed that the propagation direction of stress was 45 degrees from top to bottom of compacts. At 7-9 kJ, there was a turning phenomenon in the direction of stress propagation at the upper edge position due to the restriction of shim. As the discharge energy increased, the pores on the upper end face shifted towards reduction and concentration, ultimately forming local defects with large pores. This method could be used to improve the compaction quality of the local position of compacts. The compressive strength of compacts also increased gradually and then almost linearly, and the maximum value was 164.07 MPa. The relationships between volume strain and compaction time were obtained, R-square exceeded 0.9997 under different discharge energies, indicating high reliability. (c) 2023 Published by Elsevier B.V. on behalf of The Society of Powder Technology Japan. All rights reserved.
摘要：
Enhancing biochar's adsorption and solidification performance in compound-polluted aqueous solutions remains a crucial task for achieving the cost-effective removal of heavy metals from water bodies. The study examined the removal performances and mechanisms of Cu(II) and Cr(III) using biochar prepared from food waste at tem-peratures of 350 degrees C, 450 degrees C, and 550 degrees C (FWB-350, FWB-450, and FWB-550). FWB-450 exhibited the highest overall effectiveness in adsorbing Cu(II) and Cr(III), demonstrating the adsorption capacity (Qe) of 40.283 and 21.456 mg/g in single-solution, respectively. Thermodynamic parameters indicate that the adsorption process involves physical and chemical reactions involving heat absorption. The impact of Cr(III) on the adsorption of Cu (II) is more apparent in the mixed competitive system. The pH, the oxygen-functional groups and carbonate ion quantity of FWB are crucial in improving Cu(II) and Cr(III) adsorption by affect the hydrolysis, complexation, and ion exchange processes. The presence of alkaline earth metal ions in FWB, like Ca(II), aids in the elimination of Cu(II) and Cr(III) through ionic precipitation and ion exchange, correspondingly. Furthermore, FWB adsorbed with Cu(II) and Cr(III) is relatively less hazardous than solid waste. The study validates the resource utilization of FW and its potential application of biochar in heavy metal adsorption.
