Case Studies in Thermal Engineering最新文献

{"title":"Experimental investigations of heat transfer, energy, and exergy-based sustainability of a novel photovoltaic thermal system","authors":"Hariam Luqman Azeez ,&nbsp;Adnan Ibrahim ,&nbsp;Banw Omer Ahmed ,&nbsp;Sharul Sham Dol ,&nbsp;Ali H.A. Al-Waeli ,&nbsp;Mahmoud Jaber","doi":"10.1016/j.csite.2025.106089","DOIUrl":"10.1016/j.csite.2025.106089","url":null,"abstract":"<div><div>The inefficiency of photovoltaic systems is a major obstacle. This research proposes an advanced collector design with dimpled and petal-patterned absorber tubes, coiled twisted tape, and nanofluids combined with nanophase changing materials. The adopted methodology consists of two phases, namely experimentally characterizing the heat transfer performance of the absorber tubes and conducting indoor experiments to evaluate the performance of the new photovoltaic thermal system. The experiments were performed under different flow rates of (0.01–0.085 kg/s), irradiances (400–1000 W/m²), and six different coolants. The initial experiment revealed an inverse relationship between the mass flow rate and the thermal performance of the absorber tubes. However, mass flow rates, solar irradiances up to 1000 W/m², and using various coolants positively impacted the overall performance of the photovoltaic system. The absorber tube with dimples, petal arrays, coiled twisted tape, and nanofluid outperformed the smooth tube with water threefold. Additionally, the photovoltaic thermal system utilizing nanofluids and nanophase changing materials achieved electrical and thermal energy enhancements of 32 % and 21.2 %. The optimal design demonstrated environmental and economic viability, with total output surpassing input energy by 2.11 MWh and net CO₂ mitigation exceeding CO₂ emissions by 0.63 tons.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"70 ","pages":"Article 106089"},"PeriodicalIF":6.4,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical simulation of a multi-tube automotive thermoelectric generator for heat transfer and power generation performance","authors":"Xiao-bi Wang ,&nbsp;Jin-liang Zeng ,&nbsp;Xun Liu ,&nbsp;Chu-qi Su ,&nbsp;Xin Xiong ,&nbsp;Yi-Ping Wang","doi":"10.1016/j.csite.2025.106091","DOIUrl":"10.1016/j.csite.2025.106091","url":null,"abstract":"<div><div>To improve the performance of automotive exhaust thermoelectric generators, a numerical evaluation of automotive exhaust gas thermoelectric generators with multi-tube heat exchangers is carried out in this paper. The influence of complex flow states in corrugated tubes with different geometric structures on the device's heat transfer and power generation is analyzed. The calculation considers different mass flow rates of exhaust gas, heat transfer efficiency and entropy change based on power generation output and power generation efficiency. The results show that the increase of the height-diameter ratio of the corrugated tube is beneficial to the strength of the fluid such as the secondary flow. The rise in distance of the corrugated ring is encouraged to increase the influence range of the fluid such as the secondary flow. When the exhaust gas flow rate is 10–30 g/s, these changes can enhance the heat transfer and heat transfer efficiency compared with the smooth tube, but at the same time, the frictional resistance inside the tube will also increase. The power generation efficiency is increased to 1.2–2 times, and the maximum output power is 120W, which provides data support for optimising thermoelectric generators.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"70 ","pages":"Article 106091"},"PeriodicalIF":6.4,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal error modeling of slant bed CNC lathe spindle based on BiLSTM with data augmentation and grey wolf optimizer algorithm","authors":"Musab Alataiqeh,&nbsp;Hu Shi,&nbsp;Qiangqiang Qu,&nbsp;Xuesong Mei,&nbsp;Haitao Wang","doi":"10.1016/j.csite.2025.106090","DOIUrl":"10.1016/j.csite.2025.106090","url":null,"abstract":"<div><div>The BL20 slant bed CNC lathe is widely recognized for its compact design and precision; however, it suffers from significant thermal errors due to heat generated during operation. This study analyzes and models the thermal errors of the BL20 lathe, identifying the heat produced by the main spindle as the primary source. Utilizing finite element simulation in ANSYS, the thermal characteristics of the lathe are examined, yielding insights into the dynamics of heat transfer. Experimental data are processed using fuzzy c-means clustering and grey relational analysis, which leads to the identification of four critical temperature-sensitive points. To mitigate the challenges associated with small datasets, the Synthetic Minority Over-Sampling Technique (SMOTE) is employed for data augmentation. Furthermore, a predictive model that integrates Bidirectional Long Short-Term Memory (BiLSTM) with hyperparameter optimization via the Grey Wolf Optimizer (GWO) is developed. In comparison to traditional methods, including Convolutional Neural Networks (CNN), Support Vector Machines (SVM), and standalone BiLSTM, the GWO-BiLSTM-SMOTE model demonstrates predictive accuracy, achieving R² of 0.95384 and 0.95004 at various rotation speeds. The proposed approach showcases enhanced robustness and generalization. This study establishes a comprehensive framework for predicting thermal errors in CNC machine tools, offering valuable insights for precision machining.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"70 ","pages":"Article 106090"},"PeriodicalIF":6.4,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The enhanced heat source model and its verification of unsteady heat transfer simulation in laser quenching based on experiment","authors":"Yutong Guo,&nbsp;Gangyan Li,&nbsp;Rui Shen,&nbsp;Hui Shi,&nbsp;Baoming Hu","doi":"10.1016/j.csite.2025.106081","DOIUrl":"10.1016/j.csite.2025.106081","url":null,"abstract":"<div><div>Laser hardening, also known as laser phase transformation hardening, is a critical surface modification technology. In current engineering practice, the design of process parameters primarily relies on simulation. However, variations in actual conditions pose a significant challenge in selecting the most appropriate heat source model for accurately simulating the laser quenching process. This paper proposes a novel heat source model calculation method for simulation analysis by integrating the weighted residual Galerkin method with matrix block computation, based on temperature data acquired from the upper surface during laser quenching. By comparing the three-dimensional numerical simulation results of the transient heat transfer process of laser quenching using the proposed surface heat source model with experimental measurements obtained under corresponding conditions, it is demonstrated that the heat source model derived from this method achieves superior accuracy compared to traditional empirical models within the experimental environment utilized in this study. Furthermore, the simulation accuracy of the heat source model obtained through this computational approach remains consistently below 5 %, exhibiting minimal fluctuation even when laser power, laser state, and sample thickness vary.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"70 ","pages":"Article 106081"},"PeriodicalIF":6.4,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143828286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Entropy optimized radiative nanomaterial flow beyond classical concepts of heat and mass fluxes","authors":"T. Hayat ,&nbsp;Muhammad Fahim ,&nbsp;Aneeta Razaq ,&nbsp;Mohamed Abdalla","doi":"10.1016/j.csite.2025.106088","DOIUrl":"10.1016/j.csite.2025.106088","url":null,"abstract":"<div><div>Involvement of nanomaterials in such manufacturing processes is not underestimated. Especially the rheological nanomaterials for heat transfer are useful in processes related to cooling microchips, solar energy and thermal energy technology. Experimental studies have now witnessed the efficiency for utilization of nanoparticles regarding heat transportation enhancement. With such consideration here we analyze magnetohydrodynamic (MHD) flow of tangent hyperbolic nanomaterial. Analysis involves novel concepts of nonlinear mixed convection and entropy generation. New concepts of heat and mass fluxes for thermal and solutal transport rates are utilized. Brownian movement and thermophoresis behaviors are under consideration. Heat expression contains thermal radiation. Entropy optimization with Cattaneo-Christov theory through entire new concept of radiation is discussed. Nonlinear ordinary differential system by adequate transformations is derived. Optimal homotopy analysis technique (OHAM) for convergent solutions is implemented. Analysis of flow, temperature, rate of entropy and concentration is provided. Performances of Nusselt and Sherwood numbers for influential variables are graphically explored. Here one can conclude that flow through buoyancy ratio and magnetic field respond in a reverse manner. Temperature and entropy rate for radiation have same trend. Higher thermal Biot number lead to enhancement of Nusselt number and thermal field. Higher approximation of solutal relaxation time variable corresponds to rise of concentration. An intensification in rate of entropy through diffusion variable is witnessed.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"70 ","pages":"Article 106088"},"PeriodicalIF":6.4,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143828280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring SLT80 nanostructured lipid carriers as a novel delivery system for curcumin: Thermal analysis of experimental and theoretical approach","authors":"Mahboubeh Pishnamazi ,&nbsp;Saad M. Alshahrani ,&nbsp;Abdullah Alkhammash","doi":"10.1016/j.csite.2025.106066","DOIUrl":"10.1016/j.csite.2025.106066","url":null,"abstract":"<div><div>This study aims to develop a novel SLT80 nanostructured lipid carrier (NLC) for the encapsulation and delivery of Curcumin (CUR). CUR is a potent therapeutic agent with poor bioavailability, limiting its clinical applications. SLT80 NLCs were prepared using a solvent evaporation method and characterized using experimental techniques (UV–Vis, FTIR, DTA, SEM, and TEM) and molecular dynamics simulations. Results indicated that the SLT80 formulation maintained a slow release of CUR over twelve days, with an encapsulation efficiency that varied with drug concentration and a particle size averaging 40.15 ± 2.23 nm. CUR, were nontoxic to Human Dermal Fibroblasts (HDF) cells at the tested concentrations. Molecular dynamic simulations indicated that the CUR-loaded NLCs exhibited a stable form with a uniform nano-sized spherical shape, confirming TEM results. UV–Vis spectra of CUR-loaded SLT80 nanoparticles exhibited shifted peak maxima, consistent with both experimental and theoretical analyses. Density functional theory (DFT) analysis indicates enhanced drug solubility in the presence of the NLC, with the most stable form of complex A exhibiting a dipole moment of approximately 68.76 Debye. Favorable binding energies (E_bin: 2.02 eV) between the drug and lipid carrier support this observation and predict successful encapsulation. The developed SLT80 NLCs demonstrated high encapsulation efficiency, sustained release, and enhanced bioavailability of CUR, making them a promising drug delivery system for therapeutic applications.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"70 ","pages":"Article 106066"},"PeriodicalIF":6.4,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143817532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal conductivity enhancement in hybrid Co@MWCNT/SiC nanofluids: An experimental investigation","authors":"Bader Huwaimel ,&nbsp;Saad Alqarni","doi":"10.1016/j.csite.2025.106084","DOIUrl":"10.1016/j.csite.2025.106084","url":null,"abstract":"<div><div>In this study, we investigated the thermal conductivity characteristics of MWCNT, cobalt-encapsulated MWCNT (Co@MWCNT), and hybrid Co@MWCNT/SiC nanofluids, focusing on their thermal conductivity coefficients and specific heat under varying temperature and volume fraction conditions. The cobalt nanoparticles encapsulated in carbon nanotubes were synthesized using chemical methods and characterized through TEM, XRD, and FTIR techniques. The results indicate that cobalt nanocrystals are successfully encapsulated within carbon nanotubes, and SiC nanoparticles exhibit strong interactions with them. Notably, the hybrid composites can produce stable nanofluids with magnetic properties. The thermal conductivity coefficient is influenced by the pH of the solution, with optimal values typically found between pH 6 and 8 due to enhanced nanoparticle dispersion and reduced agglomeration in this range. As the concentration of cobalt and SiC nanoparticles increases, the thermal conductivity follows the trend of hybrid composites &gt; Co@MWCNT &gt; MWCNT. For instance, a 0.01 % increase in the volume fraction of hybrid nanoparticles can lead to a thermal capacity increase of up to 33 % compared to the base fluid. Moreover, applying a magnetic field of 0.05T can alter the thermal conductivity coefficient by enhancing the magnetic order of the cobalt atoms, often resulting in a 50 % increase in thermal capacity. Overall, the specific heat of these nanofluids varies with temperature and volume fractions, demonstrating a strong dependence on these factors. This study enhances the understanding of hybrid nanofluid properties and lays the groundwork for their practical applications in thermal management and energy systems.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"70 ","pages":"Article 106084"},"PeriodicalIF":6.4,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical investigation of the effect of three types of spiral coils on the hydrothermal behavior of fluid flow in a shell and coil heat exchanger","authors":"Ahmed Mir ,&nbsp;Seyed Hossein Hashemi Karouei ,&nbsp;Rassol Hamed Rasheed ,&nbsp;Pradeep Kumar Singh ,&nbsp;Saurav Dixit ,&nbsp;Rifaqat Ali ,&nbsp;Walid Aich ,&nbsp;Lioua Kolsi","doi":"10.1016/j.csite.2025.106078","DOIUrl":"10.1016/j.csite.2025.106078","url":null,"abstract":"<div><div>This investigation is specifically centered on quantitatively assessing the heat transfer and fluid movement within a shell and spiral tube heat exchanger comprising three distinct designs. Water was considered as the heat transfer fluid, operating within the spiral coil and the shell. In this setup, the hot fluid circulates inside the coil while the cold fluid is contained within the shell. The research covers a range of Reynolds numbers from 500 to 2000 and is split into two parts. The first part of the study examines the impact of three different spiral coil models and evaluates their thermal performance. In the second part, the best spiral coil is selected based on the findings from the first part. Three different spiral winding pitches (P) are considered: 60 mm, 50 mm, and 40 mm, with the results compared to those of a simple winding. Among the three models analyzed in the first part, model (A) with a special helical coil design exhibited the greatest thermal productivity across different Reynolds numbers. Findings showed that the helical coil with the model (A) design enhances the energy exchange between hot and cold fluid particles owing to the reinforcement of centrifugal force, intensified secondary flow, and improved radial mixing of particles. As a result, this particular coil displayed significant thermal perform effectiveness because of the intensified vortex movement of liquid particles and the thinning of thermal boundary layers. The second part of the study revealed that the thermal performance of the spiral coil with a 60 mm pitch surpassed that of the other two models. At a Reynolds number of 500, it was observed that the thermal performance coefficient increased by 60 % for the model with a 60 mm pitch, 45 % for the model with a 50 mm pitch, and 28.8 % for the model with a 40 mm pitch. This indicates a significant improvement in thermal performance as the pitch size decreases.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"70 ","pages":"Article 106078"},"PeriodicalIF":6.4,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal errors in high-speed motorized spindle: An experimental study and INFO-GRU modeling predictions","authors":"Zhaolong Li ,&nbsp;Kai Zhao ,&nbsp;Haonan Sun ,&nbsp;Yongqiang Wang ,&nbsp;Bangxv Wang ,&nbsp;JunMing Du ,&nbsp;Haocheng Zhang","doi":"10.1016/j.csite.2025.106085","DOIUrl":"10.1016/j.csite.2025.106085","url":null,"abstract":"<div><div>As the accuracy requirements of machine tools increase, so do the accuracy requirements for electric spindles. Due to the compact internal structure of the spindle and poor heat dissipation, it is prone to serious thermal errors. Therefore, this study simulates the thermal characteristics of the A02 motorized spindle and builds a thermal error analysis experimental platform to monitor the temperature and thermal elongation data of key components in real time. Four key temperature measurement points are selected using k-means clustering and the Pearson correlation coefficient method. Finally, the INFO-GRU thermal error prediction model is established and compared with the WCA-GRU and GRU models. The results show that at 2000 r/min, the INFO-GRU model has a prediction accuracy of 95.5 %, which is better than WCA-GRU (91.5 %) and GRU (88.4 %); at 6000 rpm, the INFO-GRU model has a prediction accuracy of 95.9 %, which is also significantly higher than the other two models (91.7 % and 89.3 %, respectively). The novelty of this study lies in two improvements: firstly, the number of temperature measurement points is optimized by combining a clustering algorithm with a correlation coefficient method, reducing the amount of calculation and the risk of data coupling in the prediction; secondly, the GRU model optimized by the INFO algorithm is applied to the field of electric spindles for the first time, effectively analyzing the dynamic relationship between temperature and thermal expansion. The fluctuation of the model residual is controlled within 5 μm, providing a reliable prediction scheme for temperature compensation of high-speed electric spindles.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"70 ","pages":"Article 106085"},"PeriodicalIF":6.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermo-economic comparative of open-greenhouse and sun-patio coffee drying in the Sierra Mariscal Chiapas-México","authors":"D. Santizo-Díaz,&nbsp;J.J. Flores-Prieto","doi":"10.1016/j.csite.2025.106072","DOIUrl":"10.1016/j.csite.2025.106072","url":null,"abstract":"<div><div>We show a thermal-economic comparative of open-greenhouse and sun-patio drying in the Sierra Mariscal, Chiapas-México. Thermal analyses involve drying kinetics, thermal efficiency, and drying-specific energy; economic analyses involve the investment payback period and importance parameters analysis. In an open-greenhouse, 14 kg/m² samples were spread in 12 trays (135 kg<em>/batch</em>), while in the sun-patio were 10 kg/m² of coffee bed. The initial and final samples moisture content were from 53 <em>%</em> to 11–12 <em>%</em> (<em>w.b</em>). In the comparison, the sun-patio and open-greenhouse, respectively, drying constant, water-effective diffusivity, and activation energy were on average (11.8 × 10⁻⁰⁴:9.25 × 10⁻⁰⁴), (6.08 × 10⁻¹⁰:3.42 × 10⁻⁰⁹ m²<em>/s</em>) and (14.24:12.58 kJ/mol). In open-greenhouse, the payback period better correlates with solar irradiation, 39 % more than in sun-patio. Although the drying time in the open-greenhouse increases by an average of 60.0 % compared to the sun-patio and thermal efficiency by 15.0 %, the drying-specific energy is reduced by an average of 10.6 % and payback of 2.3 <em>%</em>. At a similar payback, the open-greenhouse drying fulfills sanitary regulations contrary to sun-patio. Although in open-greenhouses, the drying time increases by 60.0 %, the drying area requirement reduces by 14.0 times. Therefore, open-greenhouse coffee drying looks like a thermo-economic alternative for coffee growers, as it improves the dried beans without increasing the cost considerably.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"70 ","pages":"Article 106072"},"PeriodicalIF":6.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}