Manufacturing Letters最新文献

{"title":"An experimental study of ultrasonic-knife cutting for a woven carbon fiber preform by an industrial robot","authors":"Hyeong Gu Kim ,&nbsp;Tae Hwa Hong ,&nbsp;Dave Kim ,&nbsp;Seong Hyeon Kim","doi":"10.1016/j.mfglet.2024.09.074","DOIUrl":"10.1016/j.mfglet.2024.09.074","url":null,"abstract":"<div><div>This study investigates the effect of the cutting process parameters on the cutting forces and the quality parameters of a woven carbon fiber preform during robotic ultrasonic-knife cutting. An ultrasonic cutting device, with a power of 1200 W, a frequency of 24 kHz, and an amplitude of 60 µm, mounted on the end effector of a six-axis degree of freedom industrial robot to make linear cuts. A three-level factorial experimental design was used to examine the effect of the feed rate (1 m/min to 5 m/min) and the knife’s attack angle (45° to 75°) on the cutting forces, the dimensional accuracy of the machined preform coupons, and the damage on the machined preform edges. The cutting force analysis results show that the increasing feed rate resulted in increasing feed force and thrust force. However, the increase of the attack angle increases the feed force but decreases the thrust force. The average width and damage of the ultrasonic knife cut preform coupons are highly related to the process conditions. The combination of the low feed rate, 1 m/min, and the low attack angle, 45°, resulted in dimensional errors ranging from 253 μm to 365 μm oversized from the programmed 15.0 mm width with no damage. When the feed became 3 m/min and 5 m/min at the attack angle of 75°, the preform coupons’ dimensional accuracy and damage formation worsened. In these conditions, the ultrasonic knife attached to the industrial robot arm could not cut the preform plate effectively, so the tows on the preform were unevenly cut or dislodged.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 581-587"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An analytical model for estimating process parameters input in L-DED based on bead geometry","authors":"Kandice S.B. Ribeiro ,&nbsp;Ana C. Reghini ,&nbsp;Reginaldo T. Coelho","doi":"10.1016/j.mfglet.2024.09.092","DOIUrl":"10.1016/j.mfglet.2024.09.092","url":null,"abstract":"<div><div>Additive manufacturing of metal alloys via laser Directed Energy Deposition (L-DED) has been gaining popularity due to its potential to repair and create new features/components, enabling new applications for built parts. The success of L-DED operations hinges on the precise control of printing parameters, including laser power, scanning speed, and powder feed rate. These parameters significantly influence heat distribution during printing, directly impacting the quality of the resulting parts. Thus, defining an efficient methodology to find a good correlation between these parameters for the printing process is crucial to boost part production, as it reduces the time-consuming trial-and-error parameter tuning process. In this context, our study introduces an analytical model that predicts printing parameters based on the deposited material volume along track lines. Deposition was carried in stainless steel 316L with different values for laser power (ranging from 500 to <span><math><mrow><mn>750</mn><mspace></mspace><mtext>W</mtext></mrow></math></span> with <span><math><mrow><mn>50</mn><mspace></mspace><mtext>W</mtext></mrow></math></span> increments), scanning speed (from 400 to <span><math><mrow><mn>700</mn><mspace></mspace><mtext>mm</mtext><mo>/</mo><mtext>min</mtext></mrow></math></span> with <span><math><mrow><mn>100</mn><mspace></mspace><mi>mm</mi><mo>/</mo><mi>min</mi></mrow></math></span> increments), and powder feed rate (<span><math><mrow><mn>6.4</mn><mo>,</mo><mn>8.0</mn></mrow></math></span> and <span><math><mrow><mn>10.0</mn><mspace></mspace><mtext>g</mtext><mo>/</mo><mtext>min</mtext></mrow></math></span>). The experimental data verified the effectiveness of the proposed model, demonstrating its potential to standardize the first step of printing process and expedite the initial search for optimal printing parameters in L-DED. The model provided accurate initial estimates of laser power, with a maximum relative error of <span><math><mrow><mn>12</mn><mo>%</mo></mrow></math></span>, particularly for the optimum mass flow rate (<span><math><mrow><mover><mrow><mi>m</mi></mrow><mrow><mo>̇</mo></mrow></mover></mrow></math></span>) of <span><math><mrow><mn>8.0</mn><mspace></mspace><mtext>g</mtext><mo>/</mo><mtext>min</mtext></mrow></math></span>. Beyond its benefits to the L-DED process, this analytical solution contributes to experimental practices by offering an efficient method for predicting material deposition volume during printing. Thus, our work underscores the significance of optimizing printing parameters to achieve high-quality parts and provides a valuable reference for future research and studies in the field of L-DED.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 742-752"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Grit size effect on HydroFlex polishing dynamics and performance","authors":"Patrick Chernjavsky ,&nbsp;Rohit Dey ,&nbsp;Jack Shanks ,&nbsp;Yinggang Tian ,&nbsp;Yihao Zheng","doi":"10.1016/j.mfglet.2024.09.060","DOIUrl":"10.1016/j.mfglet.2024.09.060","url":null,"abstract":"<div><div>Controllable, adaptable internal polishing is critical to metal additive manufactured (MAM) complex channels. Conventional fluid-based internal polishing methods are challenging to control the material removal, resulting in varied surface roughness (Sa) depending on channel length, aspect ratio (AR), and complexity. HydroFlex is an internal polishing method which drives a fixed-abrasive grinding wheel via a flexible spindle to navigate complex, high AR channels controllably and predictably removing material. Key to HydroFlex performance is the orbital motion of the grinding wheel governed by the hydrodynamic and cutting forces to achieve uniform polishing. Effect of grit size on orbital motion, and corresponding performance was experimentally evaluated. 46 µm, 76 µm, and 91 µm grit sizes were tested at a rotational speed of 50,000 rpm and a channel to wheel (C/W) ratio of 0.54 and orbital frequency and consistency, grinding force, Sa, material removal rate (MRR), and wheel wear were compared. Orbital frequency was found to directly correlate with increasing grit size and consistency of orbit shown to be highest at moderate grinding forces. Sa and MRR were inversely proportional with sub-micron roughness achieved at 0.15 g/min and 0.34 g/min corresponding to 2.2 µm Sa. Wheel wear was effected by grain pullout, attrition, and capping with all grit sizes experiencing similar wear. These findings suggest that orbital motion can be controlled through manipulation of wheel kinetics enabling precise control of grinding dynamics essential to adaptable performance in complex, non-uniform MAM channels.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 494-503"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Achieving uniform distribution of nanoparticles in oxide dispersion strengthened (ODS) SS316L through laser powder bed fusion (L-PBF)","authors":"Changyu Ma ,&nbsp;Tianqi Zheng ,&nbsp;Yu-Keng Lin ,&nbsp;Philip Mallory ,&nbsp;Xiaochun Li ,&nbsp;Y. Morris Wang ,&nbsp;Bruce Kang ,&nbsp;Bingbing Li","doi":"10.1016/j.mfglet.2024.09.095","DOIUrl":"10.1016/j.mfglet.2024.09.095","url":null,"abstract":"<div><div>Oxide dispersion strengthened (ODS) SS316L is a promising candidate for the nuclear industry for its enhanced irradiation resistance and high temperature strength. Additionally, additive manufacturing enables the design flexibility of components. Achieving a uniform distribution of oxides in ODS SS316L is one of the remaining challenges in additive manufacturing. In this paper, we investigated the effects of printing parameters on the microstructure and mechanical properties of ODS SS316L (SS316L + 0.5 wt% Y₂O₃) through laser powder bed fusion (L-PBF) additive manufacturing. The results showed that plate-like Y-Si-rich oxides (∼50 μm) were observed along the molten pool boundary in the ODS SS316L printed with nominal parameters (48.5 J/mm³) for pure SS 316L, resulting from inadequate heat input in molten pool due to the reduced laser absorption rate of powder feedstock. Through higher volumetric energy density (76.2 J/mm³) and remelting, a bimodal distribution of oxides, including nanoparticles and fine spherical oxide (∼2.5 μm), was achieved. Consequently, this contributed to increased ultimate tensile strength (UTS) and strain of ODS SS316L from 685.2.6 ± 31.4 MPa and 27.8 ± 6.2 % to 706.6 ± 36.2 MPa and 33.0 ± 6.1 %, respectively. The exploration of parameters optimization provides valuable insights into the additive manufacturing of ODS alloys with uniformly distributed nanoparticles.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 766-771"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"3D soft material printer as a mesoscale additive biomanufacturing platform for in-space manufacturing","authors":"Albert J. Patrick,&nbsp;Salil Bapat,&nbsp;Ajay P. Malshe","doi":"10.1016/j.mfglet.2024.09.015","DOIUrl":"10.1016/j.mfglet.2024.09.015","url":null,"abstract":"<div><div>With the burgeoning in-space manufacturing (ISM) industry, developing an on-demand additive manufacturing (AM) platform will be crucial for long-term space habitation. However, acute space boundary conditions, such as limited physical space, microgravity, vacuum, and others pose unique challenges for designing the printing process, the platform’s structure, and the materials’ printability. An AM platform operable in a space environment would enable production at the point of need (PoN), for example, on-demand food, nutrition, and pharmaceutical products. This research is focused on the design, fabrication, and testing of a 3D printer confined within CubeSat boundaries to study the feasibility of soft material printing aimed toward potential ISM applications. The printer unit was built using components off the shelf (COTS) while adhering to the severe spatial boundary conditions posed by the CubeSat dimensions and was tested using an edible material ink to demonstrate multi-layer prints of soft materials. Printing in ambient Earth conditions as well as under vacuum displayed consistent layer cohesion and comparison to 3D model data although vacuum prints showed visibly dehydrated prints owing to outgassing of air bubbles. The printer equipment’s structural integrity was validated under simulated launch and operation conditions using a vibration testing setup according to the NASA-recommended microsatellites standards. The results indicated that the printer assembly maintained its structural and operational integrity during and after testing. Using soft materials as the basis of testing allows scalability when expanding to more complex and structural materials to produce spare parts using a frugally engineered modular manufacturing platform.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 113-123"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Employing the electrode of different diameters to join dissimilar Al-Cu thin sheets using resistance spot welding","authors":"Rajdev Singh,&nbsp;Amit Choudhary,&nbsp;Navneet Arora","doi":"10.1016/j.mfglet.2024.09.055","DOIUrl":"10.1016/j.mfglet.2024.09.055","url":null,"abstract":"<div><div>This study aims to clarify the intricate connection between using different electrode tip diameters and the quality of spot joints. By investigating basic principles and process parameters, the research highlights how various combinations of electrode sizes affect weld quality. Specifically, to join aluminum (Al) and copper (Cu), two electrode sizes were employed: 4 mm and 8 mm tip diameter. Given that copper has higher conductivity (398 W/mK) and a higher melting temperature (1085 °C) compared to aluminum (237 W/mK and 660 °C respectively), efforts were made to enhance current density towards the copper side by using the smaller electrode tip diameter (4 mm) on that side. Experiments were conducted using two different combinations of sheet thicknesses (0.5 mm and 1 mm), revealing the need for optimized electrode tip diameter combinations for varying sheet thicknesses and materials with different thermos-physical properties. Overall, this study seeks to deepen our understanding of resistance spot welding, specifically focusing on the importance, challenges, and future prospects associated with varying electrode tip diameters in joining dissimilar metals.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 457-461"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surface insight: Leveraging high-density dataset fusion for enhanced roughness classification","authors":"Ronit Shetty,&nbsp;Ahmad Al Majali,&nbsp;Lee Wells","doi":"10.1016/j.mfglet.2024.09.022","DOIUrl":"10.1016/j.mfglet.2024.09.022","url":null,"abstract":"<div><div>The ability to assess the surface quality quickly and accurately is of immense importance in manufacturing system. Modern metrology system along with machine learning is great at classification but requires more time. Traditionally accessing surface roughness is a time-consuming process. The progress in manufacturing technology necessitates improved approaches for quality control, specifically in the categorization of surface roughness, which has a substantial impact on the performance of materials. This research study introduces a novel method for classifying surface roughness by combining image data and point cloud data to create a comprehensive model. It then compares the performance of this model with a model that just relies on image data. A comprehensive analysis is conducted in this study, where image and point cloud data is collected and analysed. Multilinear principal component analysis (MPCA) along with random forest classifier is employed to create a model that classifies the surface texture. The primary goal is to showcase the enhanced precision and comprehensive understanding offered by the fused data model compared to the model that solely relies on images.</div><div>Furthermore, the work presents a pragmatic approach for developing this enhanced model offline and applying it online in real-time production environments, with a particular focus on using only image data. This strategy is in line with the objectives of Industry 4.0, which seeks to achieve more intelligent and data-driven manufacturing processes. Subsequent investigations will prioritize expanding the model’s suitability to various manufacturing settings, particularly highlighting its capacity to ensure quality in manufacturing lines through the utilization of images.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 182-190"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving surface integrity of GH4169 alloy through magnetic-assisted cutting","authors":"Chao Tang,&nbsp;Yixuan Ye,&nbsp;Yu Zhang,&nbsp;Binghan Huang,&nbsp;Tao Huang,&nbsp;Dong Zhang,&nbsp;Xiaoming Zhang,&nbsp;Chang Ye","doi":"10.1016/j.mfglet.2024.09.077","DOIUrl":"10.1016/j.mfglet.2024.09.077","url":null,"abstract":"<div><div>GH4169 alloy presents superior properties such as high strength and resistance to high temperature, but possesses poor machinability. To ameliorate the problem and improve the machined surface integrity of GH4169 alloy, this paper focused on the application of magnetic-assisted cutting (MAC) for GH4169 alloy. In the MAC process, a permanent magnetic field (the magnetic field intensity is 0.25 T) was applied to the workpiece material during cutting, and its impact on chip morphology, tool damage and surface integrity was investigated. By comparing to traditional cutting (TC), the introduction of a magnetic field results in a reduction in the chip thickness and minimizes chip serration, leading to smoother cutting process and reduced fluctuations in cutting forces. Meanwhile, the introduction of magnetic field resulted in a substantial decrease in the notch wear and abrasion of cutting tool, and mitigated the excessive growth of built-up edge (BUE), which improved the tool life and machined surface integrity. By analyzing the machined surface at the end of TC and MAC, it was found that the surface roughness at the end of MAC was reduced by 22.4 %. Meanwhile, the cavity, side flow and debris of BUE, which tend to occur in the machined surface during the TC process, are effectively suppressed after MAC. Furthermore, Microstructural analysis of the machined surface indicated an enhancement in the dislocation density on the machined surface layer, suggesting the magnetoplastic effect of the magnetic field on GH4169 alloy.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 605-609"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kalman filter-driven state observer for thermal error compensation in machine tool digital twins","authors":"Sebastian Lang ,&nbsp;Sofia Talleri ,&nbsp;Josef Mayr ,&nbsp;Konrad Wegener ,&nbsp;Markus Bambach","doi":"10.1016/j.mfglet.2024.09.025","DOIUrl":"10.1016/j.mfglet.2024.09.025","url":null,"abstract":"<div><div>Sustainable reduction of thermal errors during production is the key challenge in modern high-precision manufacturing. Numerical compensation models provide an energy-efficient solution, but in the case of data-driven models, high-quality experimental data must be time-consuming and expensive to produce, negatively impacting overall productivity. Furthermore, robustness concerns arise in the case of new operating conditions, which were not contained in the training data. This paper presents a novel use of a Kalman filter together with model order reduced finite element models to observe the entire thermal state, which allows the subsequent solution of the mechanical model and computation of the thermal errors in real-time without requiring any training data but instead purely based on the physical system model. The effectiveness of this approach is evaluated using experiments on a thermal test bench with 16 out of 40 temperature sensors employed for observation and demonstrated on a 5-axis machine tool (MT) with 13 out of 25 temperature sensors used. Due to the combination of the reduced order model and Kalman filter these 13 temperature sensors are sufficient to represent a MT mesh of more than 350’000 elements. The entire temperature profile of the thermal test bench is reconstructed to achieve a root mean square error (RMSE) of the unobserved temperature sensors of only 2.7 °C, which accounts for more than 83% of all temperature variations and 1.3 °C for the 5-axis MT. For the thermal error of the thermal test bench, the RMSE could be reduced from <span><math><mrow><mn>67.4</mn><mspace></mspace><mi>μ</mi><mtext>m</mtext></mrow></math></span> to <span><math><mrow><mn>33.3</mn><mspace></mspace><mi>μ</mi><mtext>m</mtext></mrow></math></span>, corresponding to a reduction of 52.7 %. This could be achieved without the need for experimental data for model calibration, in a real-time capable physics-based model.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 208-218"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nanotechnology-enhanced castability of wrought aluminum alloys 2024 and 6063","authors":"Guan-Cheng Chen ,&nbsp;Xiaochun Li","doi":"10.1016/j.mfglet.2024.09.033","DOIUrl":"10.1016/j.mfglet.2024.09.033","url":null,"abstract":"<div><div>In the realm of high-performance applications, wrought aluminum alloys are esteemed for their high mechanical properties and excellent strength-to-weight ratio. However, their limited castability poses challenges in economically producing intricate structures through casting processes. To address this issue, a small proportion of TiC nanoparticles is introduced into the melts of AA 2024 and AA 6063 for nano-treating. This nano-treatment imparts several beneficial effects, including the delayed release of latent heat, inhibition of grain growth, and improvement of wettability. These effects enhance the fluidity of the melt, eliminate hot cracking, and elevate the surface quality of the castings. The outcomes underscore the promising potential of emerging nano-treatment technology in rendering traditionally non-castable wrought aluminum alloys suitable for cost-effective casting processes, ultimately delivering high-performance products for a wide range of applications.</div></div>","PeriodicalId":38186,"journal":{"name":"Manufacturing Letters","volume":"41 ","pages":"Pages 281-286"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}