Chinese Journal of Chemical Engineering最新文献

{"title":"Bubble breakup in viscous liquids at a microfluidic T-junction","authors":"Hongwei Zhu ,&nbsp;Junjie Feng ,&nbsp;Ziyi Xu ,&nbsp;Chunying Zhu ,&nbsp;Youguang Ma ,&nbsp;Wei Xu ,&nbsp;Bing Sun ,&nbsp;Taotao Fu","doi":"10.1016/j.cjche.2024.10.026","DOIUrl":"10.1016/j.cjche.2024.10.026","url":null,"abstract":"<div><div>Bubble breakup at T-junction microchannels is the basis for the numbering-up of gas−liquid two-phase flow in parallelized microchannels. This article presents the bubble breakup in viscous liquids at a microfluidic T-junction. Nitrogen is used as the gas phase, and glycerol-water mixtures with different mass concentration of glycerol as the liquid phase. The evolution of the gas−liquid interface during bubble breakup at the microfluidic T-junction is explored. The thinning of the bubble neck includes the squeezing stage and the rapid pinch-off stage. In the squeezing stage, the power law relation is found between the minimum width of the bubble neck and the time, and the values of exponents <em>α</em>₁ and <em>α</em>₂ are influenced by the viscous force. The values of pre-factors <em>m</em>₁ and <em>m</em>₂ are negatively correlated with the capillary number. In the rapid pinch-off stage, the thinning of the bubble neck is predominated by the surface tension, and the minimum width of the bubble neck can be scaled with the remaining time as power-law. The propagation of the bubble tip can be characterized by the power law between the movement distance and the time, with decreasing exponent as increased liquid viscosity.</div></div>","PeriodicalId":9966,"journal":{"name":"Chinese Journal of Chemical Engineering","volume":"78 ","pages":"Pages 44-57"},"PeriodicalIF":3.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural evolution of iron components and their action behavior on lignite combustion","authors":"Jialin Chen,&nbsp;Zhenghao Yan,&nbsp;Runxia He,&nbsp;Yanpeng Ban,&nbsp;Huacong Zhou,&nbsp;Quansheng Liu","doi":"10.1016/j.cjche.2024.10.012","DOIUrl":"10.1016/j.cjche.2024.10.012","url":null,"abstract":"<div><div>Spontaneous combustion of lignite is closely related to the inherent minerals it contains, and the iron component has a remarkable influence on the combustion property of lignite. It is very important to study the influence of iron component on the combustion reaction property of lignite to reveal autoignition mechanism of lignite and reduce autoignition of lignite. In this research, FeCl₃ and Fe₂O₃ were doped into demineralised lignite (SL⁺) by impregnation to research the effects of iron salts and iron oxides on the combustion properties of lignite. Based on the above, the effects of post-treatment method of the FeCl₃-doped coal samples, iron-salt hydrolysis products and heat-treated temperatures on the combustion property of lignite were researched, and the microstructures of the coal samples were characterised and analysed using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope-energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results demonstrate that doping with FeCl₃ increases the combustion performance of lignite, thereby reducing the ignition temperature of lignite by approximately 112 °C. In contrast, doping with Fe₂O₃ has a weaker combustion-promoting effect. XRD and XPS characterisation indicates that iron species in the coal samples doped with iron salts are highly dispersed and exhibit the FeOOH structure, whereas iron species in the coal samples doped with Fe₂O₃ exhibit the crystal form of α-Fe₂O₃. Doping of lignite with FeCl₃ and its hydrolysis product β-FeOOH reduces the ignition temperature of the coal samples. Iron species in the FeCl₃-doped coal samples after heat treatment at 300–500 °C increase the combustion property of the coal samples, whereas iron species after heat treatment at 600–900 °C have a much weaker or non-existent promoting effect on the combustion performance of the coal samples. The characterisation show a change in iron species in the coal samples with the rise in the heat treatment temperature. This change progresses from highly dispersed β-FeOOH below 300 °C to Fe₃O₄ above 400 °C. Fe₃O₄ is gradually reduced, with part of it further reduced to elementary iron at the same time as grain growth. It is believed that the gradual agglomeration of Fe₃O₄ and the appearance of elementary iron are the main reasons for the weakening or disappearance of the promoting effect on coal combustion.</div></div>","PeriodicalId":9966,"journal":{"name":"Chinese Journal of Chemical Engineering","volume":"78 ","pages":"Pages 251-262"},"PeriodicalIF":3.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the recovery of NMP waste liquid in lithium battery production by coupled pervaporation–adsorption process and evaluation of technical and economic performances","authors":"Jiayi Zhang ,&nbsp;Jiali He ,&nbsp;Guibing Wang ,&nbsp;Yu Zhao ,&nbsp;Huairong Zhou ,&nbsp;Dongliang Wang ,&nbsp;Dongqiang Zhang","doi":"10.1016/j.cjche.2024.10.006","DOIUrl":"10.1016/j.cjche.2024.10.006","url":null,"abstract":"<div><div><em>N</em>-methyl-pyrrolidone (NMP) is an important solvent for the production of lithium batteries, which causes environmental pollution and wastes resources if it is directly discharged. The current commonly used vacuum distillation recovery process suffers from high operating costs and high energy consumption. Therefore, this paper proposes a coupled pervaporation-adsorption (PV-A) process to recover NMP solvents from lithium battery production waste streams. In this process, pervaporation is used to dewater the NMP waste liquid, it was found that the water content in the raw material liquid decreased from the initial 8.3% (mass) to 0.14% (mass) after 400 min of dewatering, but the membrane separation performance decreased significantly when the water content of the raw material liquid decreased to 0.45% (mass), and at the same time, the NMP loss rate increased rapidly. An adsorption process was used to remove trace water from the remaining liquid, and the water content in the feed liquid under the optimal adsorption process conditions was reduced from 0.45% (mass) to 0.014%, which fully meets the purity requirements of electronics-grade NMP for the production of lithium batteries. Steady-state modeling and techno-economic evaluation of the proposed coupled process were carried out, and compared with vacuum distillation and pervaporation technologies, the results showed the PV-A process yielded the best techno-economic performance and the lowest environmental impact, and it can be used as an alternative process to the traditional NMP recycling technology. This study provides a new method for the recycling of NMP in the lithium battery industry.</div></div>","PeriodicalId":9966,"journal":{"name":"Chinese Journal of Chemical Engineering","volume":"78 ","pages":"Pages 273-283"},"PeriodicalIF":3.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gold nanoparticles on Fe-doped Co3O4 for enhanced low-temperature CO oxidation","authors":"Jianfang Liu,&nbsp;Hongwei Huang,&nbsp;Jie Yang,&nbsp;Laishuan Liu,&nbsp;Yu Li","doi":"10.1016/j.cjche.2024.10.015","DOIUrl":"10.1016/j.cjche.2024.10.015","url":null,"abstract":"<div><div>A series of Au/Co_<em>x</em>Fe_3-<em>x</em>O₄ catalysts was synthesized using the sol-deposition method by depositing 2–5 nm Au particles on Fe-doped Co₃O₄. Co₂FeO₄, with a Co/Fe molar ratio of 2:1, exhibited higher specific surface area, Co³⁺/Co²⁺ ratio, and oxygen vacancy content compared to Co₃O₄. As a result, it displayed better performance in CO oxidation, achieving a total conversion temperature (<em>T</em>₁₀₀) of 96 °C. Au greatly improved the catalytic efficiency of all Co_<em>x</em>Fe_3-<em>x</em>O₄ samples, with the 0.2%Au/Co₂FeO₄ catalyst achieving a further decrease in <em>T</em>₁₀₀ to 73 °C. Stability tests conducted at room temperature on the 1%Au/Co_<em>x</em>Fe_3-<em>x</em>O₄ catalysts demonstrated a slowed deactivation rate after Fe-doping. The reaction pathway for CO oxidation catalyzed by Au/Co₂FeO₄ followed the Mars-van Krevelen mechanism.</div></div>","PeriodicalId":9966,"journal":{"name":"Chinese Journal of Chemical Engineering","volume":"78 ","pages":"Pages 175-186"},"PeriodicalIF":3.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CFD investigation in the temperature effect on coal catalytic hydrogasification in the pressurized bubbling fluidized bed","authors":"Yin Zhang ,&nbsp;Shuai Yan ,&nbsp;Zihong Xia ,&nbsp;Caixia Chen ,&nbsp;Xuan Qu ,&nbsp;Jicheng Bi","doi":"10.1016/j.cjche.2024.10.020","DOIUrl":"10.1016/j.cjche.2024.10.020","url":null,"abstract":"<div><div>Temperature is a critical factor influencing the performance of coal catalytic hydrogasification in bubbling fluidized bed gasifiers. Numerical simulations at various temperatures (1023 K, 1073 K, 1123 K, and 1173 K) are conducted to elucidate the mechanisms by which temperature affects bubble size, global reaction performance, and particle-scale reactivity. The simulation results indicate that bubble size increases at elevated temperatures, while H₂-char hydrogasification reactivity is enhanced. Particle trajectory analyses reveal that particles sized between 100 and 250 μm undergo intense char hydrogasification in the dense phase, contributing to the formation of hot spots. To assess the impact of temperature on the particle-scale flow-transfer-reaction process, the dimensionless quantities of Reynolds, Nusselt, and Sherwood numbers, along with the solids dispersion coefficient, are calculated. It is found that higher temperatures inhibit bubble-induced mass and heat transfer. In general, 3 MPa, 1123 K, and 3–4 fluidization numbers are identified as the optimal conditions for particles ranging from 0 to 350 μm. These findings provide valuable insights into the inherent interactions between temperature and gas-particle reaction.</div></div>","PeriodicalId":9966,"journal":{"name":"Chinese Journal of Chemical Engineering","volume":"78 ","pages":"Pages 205-217"},"PeriodicalIF":3.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physically-consistent-WGAN based small sample fault diagnosis for industrial processes","authors":"Siyu Tang,&nbsp;Hongbo Shi,&nbsp;Bing Song,&nbsp;Yang Tao,&nbsp;Shuai Tan","doi":"10.1016/j.cjche.2024.10.028","DOIUrl":"10.1016/j.cjche.2024.10.028","url":null,"abstract":"<div><div>In real industrial scenarios, equipment cannot be operated in a faulty state for a long time, resulting in a very limited number of available fault samples, and the method of data augmentation using generative adversarial networks for smallsample data has achieved a wide range of applications. However, the current generative adversarial networks applied in industrial processes do not impose realistic physical constraints on the generation of data, resulting in the generation of data that do not have realistic physical consistency. To address this problem, this paper proposes a physical consistency-based WGAN, designs a loss function containing physical constraints for industrial processes, and validates the effectiveness of the method using a common dataset in the field of industrial process fault diagnosis. The experimental results show that the proposed method not only makes the generated data consistent with the physical constraints of the industrial process, but also has better fault diagnosis performance than the existing GAN-based methods.</div></div>","PeriodicalId":9966,"journal":{"name":"Chinese Journal of Chemical Engineering","volume":"78 ","pages":"Pages 163-174"},"PeriodicalIF":3.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Continuous-flow synthesis of pentaerythritol: Alkalinity release of sodium solvation cage to control aldol and cannizzaro reactions","authors":"Zhengguang Wang ,&nbsp;Xin Qu ,&nbsp;Xingke Yuan ,&nbsp;Zhanpeng Gao ,&nbsp;Niu Hu ,&nbsp;Jiansheng Wei ,&nbsp;Wenpeng Li ,&nbsp;Zhirong Yang ,&nbsp;Jingtao Wang","doi":"10.1016/j.cjche.2024.11.005","DOIUrl":"10.1016/j.cjche.2024.11.005","url":null,"abstract":"<div><div>Continuous-flow upgrading of pentaerythritol synthesis technology <em>via</em> base-catalyzed aldol and Cannizzaro reactions of formaldehyde and acetaldehyde faces the challenge of effectively controlling the critical side reaction of hydroxymethyl acetaldehyde (HA) to the acrolein intermediate. Here, we first identified the forms of industrial formaldehyde as methane diol that easily converts to the alkaline formaldehyde under alkaline (NaOH) environment. The carbonyl group of alkaline formaldehyde induces deprotonation of acetaldehyde instead of the recognized base-hydroxyl group-induced deprotonation, and it needs to overcome only 18.31 kcal·mol⁻¹ (1 kcal = 4.186 kJ) energy barrier to form key intermediates of HA. The sodium solvation cage formed by NaOH hexa-coordinated formaldehyde effectively inhibits the alkalinity, thus contributing to a high energy barrier (46.21 kcal·mol⁻¹) to unwanted acrolein formation. In addition, the solvation cage gradually opens to increase the alkalinity with the consumption of formaldehyde, thus facilitating the subsequent Cannizzaro reaction (to overcome 11.77 kcal·mol⁻¹). In comparison, strong alkalinity promotes the formation of acrolein (36.65 kcal·mol⁻¹) to initiate the acetal side reaction, while weak alkalinity reduces the possibility of the Cannizzaro reaction (to overcome 20.44 kcal·mol⁻¹). This theoretically reveals the importance of the segmented feeding of weak and strong bases to successively control the aldol reaction and Cannizzaro reaction, and the combination of Na₂CO₃ or HCOONa with NaOH improves the pentaerythritol yield by 7%−13% compared to that of NaOH alone (70% yield) within 1 minute at a throughput of 155.7 ml·min^-1.</div></div>","PeriodicalId":9966,"journal":{"name":"Chinese Journal of Chemical Engineering","volume":"79 ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143528992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent advances in time-series analysis methods for identifying fluid flow characteristics in stirred tank reactors","authors":"Xiaoyu Tang ,&nbsp;Facheng Qiu ,&nbsp;Peiqiao Liu ,&nbsp;Yundong Wang ,&nbsp;Hong Li ,&nbsp;Zuohua Liu","doi":"10.1016/j.cjche.2024.09.028","DOIUrl":"10.1016/j.cjche.2024.09.028","url":null,"abstract":"<div><div>Leveraging big data signal processing offers a pathway to the development of artificial intelligence-driven equipment. The analysis of fluid flow signals and the characterization of fluid flow behavior are of critical in two-phase flow studies. Significant research efforts have focused on discerning flow regimes using various signal analysis methods. In this review, recent advances in time series signals analysis algorithms for stirred tank reactors have been summarized, and the detailed methodologies are categorized into the frequency domain methods, time-frequency domain methods, and state space methods. The strengths, limitations, and notable findings of each algorithm are highlighted. Additionally, the interrelationships between these methodologies have also been discussed, as well as the present progress achieved in various applications. Future research directions and challenges are also predicted to provide an overview of current research trends in data mining of time series for analyzing flow regimes and chaotic signals. This review offers a comprehensive summary for extracting and characterizing fluid flow behavior and serves as a theoretical reference for optimizing the characterization of chaotic signals in future research endeavors.</div></div>","PeriodicalId":9966,"journal":{"name":"Chinese Journal of Chemical Engineering","volume":"77 ","pages":"Pages 310-327"},"PeriodicalIF":3.7,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Controllable synthesis of hydrogen-bonded organic framework encapsulated enzyme for continuous production of chiral hydroxybutyric acid in a two-stage cascade microreactor","authors":"Danyang Zhao,&nbsp;Qiangqiang Xue,&nbsp;Yujun Wang,&nbsp;Guangsheng Luo","doi":"10.1016/j.cjche.2024.09.020","DOIUrl":"10.1016/j.cjche.2024.09.020","url":null,"abstract":"<div><div>Constructing a framework carrier to stabilize protein conformation, induce high embedding efficiency, and acquire low mass-transfer resistance is an urgent issue in the development of immobilized enzymes. Hydrogen-bonded organic frameworks (HOFs) have promising application potential for embedding enzymes. In fact, no metal involvement is required, and HOFs exhibit superior biocompatibility, and free access to substrates in mesoporous channels. Herein, a facile <em>in situ</em> growth approach was proposed for the self-assembly of alcohol dehydrogenase encapsulated in HOF. The micron-scale bio-catalytic composite was rapidly synthesized under mild conditions (aqueous phase and ambient temperature) with a controllable embedding rate. The high crystallinity and periodic arrangement channels of HOF were preserved at a high enzyme encapsulation efficiency of 59%. This bio-composite improved the tolerance of the enzyme to the acid-base environment and retained 81% of its initial activity after five cycles of batch hydrogenation involving NADH coenzyme. Based on this controllably synthesized bio-catalytic material and a common lipase, we further developed a two-stage cascade microchemical system and achieved the continuous production of chiral hydroxybutyric acid (R-3-HBA).</div></div>","PeriodicalId":9966,"journal":{"name":"Chinese Journal of Chemical Engineering","volume":"77 ","pages":"Pages 175-184"},"PeriodicalIF":3.7,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CPAM-assisted synthesis of NaA zeolite membrane on macroporous mullite hollow fiber for ethanol dehydration by pervaporation","authors":"Liqin Tang,&nbsp;Xiang Jin,&nbsp;Bing Gao,&nbsp;Xuechao Gao,&nbsp;Xuehong Gu","doi":"10.1016/j.cjche.2024.09.016","DOIUrl":"10.1016/j.cjche.2024.09.016","url":null,"abstract":"<div><div>Due to the low transport resistance, mullite hollow fiber (HF) could be regarded as a promising support for preparation of NaA zeolite membranes. However, insufficient coverage and undesired seed penetration often occur in the seeding step of the mullite support due to the rough surfaces with ultra-large macropores (2–4 μm). This leads to poor intergrowth of the membrane layer. To solve this issue, cationic polyacrylamide (CPAM) was employed to modify the chemical and electrostatic properties of the mullite HF surface, where the electrostatic attraction between the surface and seed crystals could significantly promote the coating effect. In the seeding, the original seeds (3.2 μm) were mixed with the ball-milled seeds (0.3 μm) to improve the seed coverage, <em>i.e.,</em> the original seed was used to block the macropores on the support surface to prevent the penetration of small seeds, while the decked ball-milled seed was used to provide sufficient active sites to induce the intergrowth of the zeolite crystals. The effects of the concentration of CPAM, mixed mass ratio of seeds, and seed concentration on the preparation of NaA zeolite membranes were systematically examined, where the separation performances were characterized by pervaporation (PV) dehydration of 90% (mass) ethanol/water mixtures at 75 °C. The results indicated that under a CPAM concentration of 0.7% (mass), an equivalent mass ratio of mixed seeds in a seed concentration of 1.0% (mass), the prepared mullite HF supported NaA zeolite membrane yielded the best PV performance, where the permeation flux and separation factor corresponded to 5.45 kg·m⁻²·h⁻¹ and 10000, respectively, being sufficient for industrial applications.</div></div>","PeriodicalId":9966,"journal":{"name":"Chinese Journal of Chemical Engineering","volume":"77 ","pages":"Pages 66-80"},"PeriodicalIF":3.7,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}