Progress in Energy and Combustion Science最新文献

{"title":"Internationalism in climate action and China’s role","authors":"Danae Kyriakopoulou, L. Xia, Chunping Xie","doi":"10.1088/2516-1083/acb4d6","DOIUrl":"https://doi.org/10.1088/2516-1083/acb4d6","url":null,"abstract":"The world is facing dual challenges of generating an economic recovery from the COVID-19 crisis, and transitioning to a low-carbon economy to tackle climate change. Strongly interrelated global challenges will require an integrated and coordinated response by all countries to manage the risk and lay the foundation for building back better. As the world’s biggest emitter and the second-largest economy, China is a very important player in international collaboration and coordination in climate action. Against this backdrop, this paper looks into the increasingly crucial role that China is playing in global climate action, especially focusing on three aspects: China’s domestic and foreign policymaking for the energy transition; its role in promoting multilateralism and international collaboration on building a sustainable world; and how it could accelerate climate action and diplomacy through research, development and innovation. In the critical decade of the 2020s, China has a great opportunity to further transform and upgrade its energy and industrial structures, promote research, development and the application of green and low-carbon technologies and intensify international climate cooperation on climate change. China should aim to be at the forefront of raising climate ambition and accelerating climate action for a sustainable and more equitable world.","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"20 1","pages":""},"PeriodicalIF":29.5,"publicationDate":"2023-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81952480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fundamentals of window-ejected fire plumes from under-ventilated compartment fires: Recent progresses and perspectives","authors":"Xiepeng Sun ,&nbsp;Fei Tang ,&nbsp;Kaihua Lu ,&nbsp;Fei Ren ,&nbsp;Congling Shi ,&nbsp;Bart Merci ,&nbsp;Longhua Hu","doi":"10.1016/j.pecs.2022.101039","DOIUrl":"https://doi.org/10.1016/j.pecs.2022.101039","url":null,"abstract":"<div><p>This paper intends to provide a comprehensive state-of-art review of recent progresses and to formulate perspectives on window-ejected fire plumes, originating from under-ventilated compartment fires (known as ‘Regime I’ fires). Various external boundary conditions are considered, as they contribute to the fire and plume dynamics, and as such affect decisions on fire prevention and firefighting. Hence this is an important fire combustion topic of both fundamental and practical significance. After discussing the general fundamentals, the paper focuses particularly on recent progresses on quantifying the ejected fire plume behavior: constrained by the presence of walls; at sub-atmospheric pressure (for fires at high altitudes) and under complex flow conditions caused by wind. Experiments, theoretical scaling analysis and basic models are reviewed. The key points cover systematically: the compartment fire evolution (and hence criteria for flame ejection through the window); flame interaction and merging behavior from two windows; air entrainment mechanisms and characteristic parameters (flame structure/dimensions, temperature profile and heat flux) of window-ejected fire plumes. Meanwhile, the limitations of present research and future challenges are also discussed.</p></div>","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"94 ","pages":"Article 101039"},"PeriodicalIF":29.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2622298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Opportunities and challenges in using particle circulation loops for concentrated solar power applications","authors":"Gilles Flamant ,&nbsp;Benjamin Grange ,&nbsp;John Wheeldon ,&nbsp;Frédéric Siros ,&nbsp;Benoît Valentin ,&nbsp;Françoise Bataille ,&nbsp;Huili Zhang ,&nbsp;Yimin Deng ,&nbsp;Jan Baeyens","doi":"10.1016/j.pecs.2022.101056","DOIUrl":"https://doi.org/10.1016/j.pecs.2022.101056","url":null,"abstract":"&lt;div&gt;&lt;p&gt;Concentrated Solar Power (CSP) is an electricity generation technology that concentrates solar irradiance through heliostats onto a small area, the receiver, where a heat transfer medium, currently a fluid (HTF), is used as heat carrier towards the heat storage and power block. It has been under the spotlight for a decade as one of the potential or promising renewable and sustainable energy technologies.&lt;/p&gt;&lt;p&gt;Using gas/solid suspensions as heat transfer medium in CSP has been advocated for the first time in the 1980′s and this novel concept relies on its possible application throughout the full CSP plant, i.e., in heat harvesting, conveying, storage and re-use, where it offers major advantages in comparison with the common heat transfer fluids such as water/steam, thermal fluids or molten salt. Although the particle suspension has a lower heat capacity than molten salts, the particle-driven system can operate without temperature limitation (except for the maximum allowable wall temperature of the receiver tubes), and it can also operate with higher hot-cold temperature gradients. Suspension temperatures of over 800 °C can be tolerated and achieved, with additional high efficiency thermodynamic systems being applicable. The application of high temperature particulate heat carriers moreover expands the possible thermodynamic cycles from Rankine steam cycles to Brayton gas cycles and even to combined electricity generating cycles.&lt;/p&gt;&lt;p&gt;This review paper deals with the development of the particle-driven CSP and assesses both its background fundamentals and its energy efficiency. Among the cited systems, batch and continuous operations with particle conveying loops are discussed. A short summary of relevant particle-related properties, and their use as heat transfer medium is included. Recent pilot plant experiments have demonstrated that a novel bubbling fluidized bed concept, the upflow bubbling fluidized bed (UBFB), recently adapted to use bubble rupture promoters and called dense upflow fluidized bed (DUFB), offers a considerable potential for use in a solar power tower plant for its excellent heat transfer at moderate to high receiver capacities.&lt;/p&gt;&lt;p&gt;For all CSP applications with particle circulation, a major challenge remains the transfer of hot and colder particles among the different constituents of the CSP system (receiver to storage, power block and return loop to the top of the solar tower). Potential conveying modes are discussed and compared. Whereas in solar heat capture, bubbling fluidized beds, particle falling films, vortex and rotary furnaces, among others, seem appropriate, both moving beds and bubbling fluidized beds are recommended in the heat storage and re-use, and examined in the review.&lt;/p&gt;&lt;p&gt;Common to all CSP applications are the thermodynamic cycles in the power block, where different secondary working fluids can be used to feed the turbines. These thermodynamic cycles are discussed in detail and the current or f","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"94 ","pages":"Article 101056"},"PeriodicalIF":29.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1886079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reduction in greenhouse gas and other emissions from ship engines: Current trends and future options","authors":"Päivi T. Aakko-Saksa ,&nbsp;Kati Lehtoranta ,&nbsp;Niina Kuittinen ,&nbsp;Anssi Järvinen ,&nbsp;Jukka-Pekka Jalkanen ,&nbsp;Kent Johnson ,&nbsp;Heejung Jung ,&nbsp;Leonidas Ntziachristos ,&nbsp;Stéphanie Gagné ,&nbsp;Chiori Takahashi ,&nbsp;Panu Karjalainen ,&nbsp;Topi Rönkkö ,&nbsp;Hilkka Timonen","doi":"10.1016/j.pecs.2022.101055","DOIUrl":"https://doi.org/10.1016/j.pecs.2022.101055","url":null,"abstract":"<div><p>The impact of ship emission reductions can be maximised by considering climate, health and environmental effects simultaneously and using solutions fitting into existing marine engines and infrastructure. Several options available enable selecting optimum solutions for different ships, routes and regions. Carbon-neutral fuels, including low-carbon and carbon-negative fuels, from biogenic or non-biogenic origin (biomass, waste, renewable hydrogen) could resemble current marine fuels (diesel-type, methane and methanol). The carbon-neutrality of fuels depends on their Well-to-Wake (WtW) emissions of greenhouse gases (GHG) including carbon dioxide (CO₂), methane (CH₄), and nitrous oxide emissions (N₂O). Additionally, non-gaseous black carbon (BC) emissions have high global warming potential (GWP). Exhaust emissions which are harmful to health or the environment need to be equally removed using emission control achieved by fuel, engine or exhaust aftertreatment technologies. Harmful emission species include nitrogen oxides (NO_x), sulphur oxides (SO_x), ammonia (NH₃), formaldehyde, particle mass (PM) and number emissions (PN). Particles may carry polyaromatic hydrocarbons (PAHs) and heavy metals, which cause serious adverse health issues. Carbon-neutral fuels are typically sulphur-free enabling negligible SO_x emissions and efficient exhaust aftertreatment technologies, such as particle filtration. The combinations of carbon-neutral drop-in fuels and efficient emission control technologies would enable (near-)zero-emission shipping and these could be adaptable in the short- to mid-term. Substantial savings in external costs on society caused by ship emissions give arguments for regulations, policies and investments needed to support this development.</p></div>","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"94 ","pages":"Article 101055"},"PeriodicalIF":29.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1867846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Critical review on the synthesis, characterization, and application of highly efficient metal chalcogenide catalysts for fuel cells","authors":"Tasnim Eisa ,&nbsp;Mohammad Ali Abdelkareem ,&nbsp;Dipak A. Jadhav ,&nbsp;Hend Omar Mohamed ,&nbsp;Enas Taha Sayed ,&nbsp;Abdul Ghani Olabi ,&nbsp;Pedro Castaño ,&nbsp;Kyu-Jung Chae","doi":"10.1016/j.pecs.2022.101044","DOIUrl":"https://doi.org/10.1016/j.pecs.2022.101044","url":null,"abstract":"<div><p>The shift in the energy sector toward green resources makes fuel cells increasingly relevant as a supplier of green and sustainable energy. However, factors such as expensive catalysts, anodic poisoning, and fuel crossover reduce the lifetime and performance of the fuel cells, necessitating catalysis improvement. This review article presents the unique capabilities of metal chalcogenides (MC) as tailored catalysts, elucidating their synthesis, testing techniques, and performance evaluations. MC catalysts are matured via various physical and chemical methods to control their morphology, quantity, dimension, and size. Upon synthesis, the catalyst performance is quantified using three-electrode cells, followed by tests in fuel-cell prototypes. As anodic catalysts, MCs oxidize various fuels such as methanol, ethanol, urea, and impure H₂ at high current densities and low onset potentials, while hindering the poisoning species. As cathodic catalysts, MCs exhibit current values similar to that exhibited by their noble metal counterparts while reducing oxygen selectively in the vicinity of the fuels via four electron transfers at a wide range of potentials.</p></div>","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"94 ","pages":"Article 101044"},"PeriodicalIF":29.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1886078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Volumetric emission tomography for combustion processes","authors":"Samuel J. Grauer ,&nbsp;Khadijeh Mohri ,&nbsp;Tao Yu ,&nbsp;Hecong Liu ,&nbsp;Weiwei Cai","doi":"10.1016/j.pecs.2022.101024","DOIUrl":"https://doi.org/10.1016/j.pecs.2022.101024","url":null,"abstract":"<div><p>This is a comprehensive, critical, and pedagogical review of volumetric emission tomography for combustion processes. Many flames that are of interest to scientists and engineers are turbulent and thus inherently three-dimensional, especially in practical combustors, which often contain multiple interacting flames. Fortunately, combustion leads to the emission of light, both spontaneously and in response to laser-based stimulation. Therefore, images of a flame convey path-integrated information about the source of light, and a tomography algorithm can be used to reconstruct the spatial distribution of the light source, called emission tomography. In a carefully designed experiment, reconstructions can be post-processed using chemical kinetic, spectroscopic, and/or transport models to extract quantitative information. This information can be invaluable for benchmarking numerical solutions, and volumetric emission tomography is increasingly relied upon to paint a more complete picture of combustion than point, linear, or planar tools. Steady reductions in the cost of optical equipment and computing power, improvements in imaging technology, and advances in reconstruction algorithms have enabled a suite of three-dimensional sensors that are regularly used to characterize combustion. Four emission modalities are considered in this review: chemiluminescence, laser-induced fluorescence, passive incandescence, and laser-induced incandescence. The review covers the reconstruction algorithms, imaging models, camera calibration techniques, signal physics, instrumentation, and post-processing methods needed to conduct volumetric emission tomography and interpret the results. Limitations of each method are discussed and a survey of key applications is presented. The future of volumetric combustion diagnostics is considered, with special attention paid to the advent and promise of machine learning as well as spectrally-resolved volumetric measurement techniques.</p></div>","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"94 ","pages":"Article 101024"},"PeriodicalIF":29.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3137476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A synthesis and review of exacerbated inequities from the February 2021 winter storm (Uri) in Texas and the risks moving forward","authors":"Sergio Castellanos, Jerry R. Potts, Helena R. Tiedmann, S. Alverson, Y. R. Glazer, A. Robison, Suzanne Russo, Dana Harmon, Bobuchi Ken-Opurum, Margo Weisz, Frances Acuna, K. Stephens, K. Faust, M. Webber","doi":"10.1088/2516-1083/aca9b4","DOIUrl":"https://doi.org/10.1088/2516-1083/aca9b4","url":null,"abstract":"A severe winter storm in February 2021 impacted multiple infrastructure systems in Texas, leaving over 13 million people without electricity and/or water, potentially $100 billion in economic damages, and almost 250 lives lost. While the entire state was impacted by temperatures up to 10 °C colder than expected for this time of year, as well as levels of snow and ice accumulation not observed in decades, the responses and outcomes from communities were inconsistent and exacerbated prevailing social and infrastructure inequities that are still impacting those communities. In this contribution, we synthesize a subset of multiple documented inequities stemming from the interdependence of the water, housing, transportation, and communication sectors with the energy sector, and present a summary of actions to address the interdependency of infrastructure system inequities.","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"51 1","pages":""},"PeriodicalIF":29.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90848079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrogen storage in liquid hydrogen carriers: recent activities and new trends","authors":"T. H. Ulucan, S. Akhade, Ajith Ambalakatte, T. Autrey, A. Cairns, Ping Chen, Y. Cho, F. Gallucci, Wenbo Gao, J. Grinderslev, Katarzyna Grubel, T. Jensen, P. D. de Jongh, J. Kothandaraman, K. Lamb, Young-Su Lee, C. Makhloufi, P. Ngene, Pierre Olivier, C. J. Webb, Berenger Wegman, B. Wood, C. Weidenthaler","doi":"10.1088/2516-1083/acac5c","DOIUrl":"https://doi.org/10.1088/2516-1083/acac5c","url":null,"abstract":"Efficient storage of hydrogen is one of the biggest challenges towards a potential hydrogen economy. Hydrogen storage in liquid carriers is an attractive alternative to compression or liquefaction at low temperatures. Liquid carriers can be stored cost-effectively and transportation and distribution can be integrated into existing infrastructures. The development of efficient liquid carriers is part of the work of the International Energy Agency Task 40: Hydrogen-Based Energy Storage. Here, we report the state-of-the-art for ammonia and closed CO2-cycle methanol-based storage options as well for liquid organic hydrogen carriers.","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"324 1","pages":""},"PeriodicalIF":29.5,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76640923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Liquid air energy storage technology: a comprehensive review of research, development and deployment","authors":"Ting Liang, Tongtong Zhang, Xipeng Lin, Tafone Alessio, Mathieu Legrand, Xiufen He, H. Kildahl, Chang Lu, Haisheng Chen, A. Romagnoli, L. Wang, Qing He, Yongliang Li, Lizhong Yang, Yulong Ding","doi":"10.1088/2516-1083/aca26a","DOIUrl":"https://doi.org/10.1088/2516-1083/aca26a","url":null,"abstract":"Liquid air energy storage (LAES) uses air as both the storage medium and working fluid, and it falls into the broad category of thermo-mechanical energy storage technologies. The LAES technology offers several advantages including high energy density and scalability, cost-competitiveness and non-geographical constraints, and hence has attracted a growing interest in recent years. As a result, several reviews have been published on the topic. However, these reviews covered little in the following aspects of LAES: dynamic simulation and optimisation, key components for LAES, LAES applications through integration, and unified economic and cost models for LAES. This article provides a comprehensive review on the LAES technology and fills the above gaps. Apart from applications in electrical grids such as peak-shaving, load shifting, and dealing with intermittency of renewable generation, the review also shows a diverse range of other LAES applications through integration, including waste heat and cold energy recovery and utilisation, multi-energy vector service provision, and sector coupling for chemical production and carbon capture. The review also leads to the recommendation of several areas for future research and development, including dynamic characteristics of whole LAES system integrated with renewables and end users; thermo-economic and dynamic optimization of stand-alone LAES and integrated systems; and experimental study on commercial systems.","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"51 1","pages":""},"PeriodicalIF":29.5,"publicationDate":"2022-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75108243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advances in biomass torrefaction: Parameters, models, reactors, applications, deployment, and market","authors":"Sonal K. Thengane ,&nbsp;Kevin S. Kung ,&nbsp;Alberto Gomez-Barea ,&nbsp;Ahmed F. Ghoniem","doi":"10.1016/j.pecs.2022.101040","DOIUrl":"https://doi.org/10.1016/j.pecs.2022.101040","url":null,"abstract":"<div><p>Biomass is a promising renewable source that can reduce fossil fuel consumption and associated greenhouse gas emissions, but some of its characteristics make it difficult to use in its raw form. Torrefaction<span> has been proposed as a thermochemical pretreatment<span><span> to upgrade biomass for direct applications such as combustion and gasification, biochar and chemicals production, while reducing its transportation cost and increasing its shelf-life. Research, development, and demonstration of biomass torrefaction technologies have advanced during the last few decades, but many science and engineering fundamentals as well as technological challenges remain, especially in the areas of reaction thermodynamics and kinetics, reactor models and design, large-scale implementation, and environmental performance. In this paper we present a comprehensive review of recent developments in biomass torrefaction research and technology focusing on kinetics, particle and reactor scale models, and reactor designs. The impacts of torrefaction as a pretreatment of biomass on subsequent conversion processes, and the novel applications of torrefied biomass are discussed. The </span>energy management<span>, environmental impacts, economic and market potential of the technology as well as the deployment options are also addressed. There is no best universal torrefaction reactor and hence the choice should be made based on the biomass feedstock<span> and the expected production rate and application. To reduce process costs and competition with other uses of biomass, the utilization of either waste or environmentally sustainable, more abundant, and faster growing biomass should be targeted for this technology. Torrefied biomass produced at higher temperatures resemble pyrolysis biochar in several properties thereby making it suitable for most biochar applications. Finally, considering the need to identify the bottlenecks that potentially could limit the use of torrefaction, and its preceding or subsequent processes, the future prospects, challenges, and opportunities of torrefaction technology are presented.</span></span></span></span></p></div>","PeriodicalId":410,"journal":{"name":"Progress in Energy and Combustion Science","volume":"93 ","pages":"Article 101040"},"PeriodicalIF":29.5,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1695771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}