An optimized generic cerebral tumor growth modeling framework by coupling biomechanical and diffusive models with treatment effects

Mathematical modeling of cerebral tumor growth is of great importance in clinics. It can help in understanding the physiology of tumor growth, future prognosis of tumor shape and volume, quantify tumor aggressiveness, and the response to therapy. This can be achieved at macroscopic level using medical imaging techniques (particularly, magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI)) and complex mathematical models which are either diffusive or biomechanical. We propose an optimized generic modeling framework that couples tumor diffusivity and infiltration with the induced mass effect. Tumor cell diffusivity and infiltration are captured using a modified reaction-diffusion model with logistic proliferation term. On the other hand, tumor mass effect is modeled using continuum mechanics formulation. In addition, we consider the treatment effects of both radiotherapy and chemotherapy. The efficacy of chemotherapy is included via an adaptively modified log-kill method to consider tissue heterogeneity while the efficacy of radiotherapy is considered using the linear quadratic model. Moreover, our model efficiently utilizes the diffusion tensor of the diffusion tensor imaging. Furthermore, we optimize the tumor growth parameters to be patient-specific using bio-inspired particle swarm optimization (PSO) algorithm. Our model is tested on an atlas and real MRI scans of 8 low grade gliomas subjects. Experimental results show that our model efficiently incorporates both treatment effects in the growth modelingprocess. In addition, simulated growths of our model have high accuracy in terms of Dice coefficient (average 87.1%) and Jaccard index (77.14%) when compared with the follow up scans (ground truth) and other models as well.     

Diffusion behavior and reactions between Al and Ca in Mg alloys by diffusion couples

The diffusion behavior and reactions between Al and Ca in Mg alloys by diffusion couple method were investigated. Results demonstrate that Al_2Ca is the only phase existing in the diffusion reaction layers.The volume fraction of Al_2Ca in diffusion reaction layers increases linearly with temperature. The standard enthalpy of formation for intermetallic compounds was rationalized on the basis of the Miedema model. Al-Ca intermetallic compounds were preferable to form in the Mg-Al-Ca ternary system under the same conditions. Over the range of 350–400?C, the structure of Al_2Ca is more stable than that of Al_4Ca, Al_(14)Ca_(13) and Al_3Ca_8. The growth constants of the layer Ⅰ, layer Ⅱ and entire diffusion reaction layers were determined. The activation energies for the growth of the layer Ⅰ, layer Ⅱ and entire diffusion reaction layers were(80.74 ± 3.01) k J/mol,(93.45 ± 2.12) k J/mol and(83.52 ± 1.50) k J/mol, respectively.In layer Ⅰ and Ⅱ, Al has higher integrated interdiffusion coefficients D~(Int, layer)ithan Ca. The average effective interdiffusion coefficients D_(Al)~(eff) values are higher than D_(Ca)~(eff) in the layer Ⅰ and Ⅱ.     

Ultrasonic vibration assisted tungsten inert gas welding of dissimilar magnesium alloys

The effects of ultrasonic vibration assisted (UVA) treatment on the microstructures and mechanical properties of MB3/AZ31 dissimilar magnesium (Mg) alloy joints were studied by microstructural characterization, micro-hardness testing and tensile testing. Results indicate that the welding pores are eliminated and coarse ??-Mg grains of fusion zone are refined to 26 ??m, owing to the acoustic streaming effect and cavitation effect induced by the UVA treatment with an optimal ultrasonic power of 1.0 kW. In addition, Mg₁₇Al₁₂ precipitation phases are fine and uniformly distributed in the whole fusion zone of weldment. Micro-hardness of fusion zone of the Mg alloy joints increases to 53.5 HV after UVA process, and the maximum tensile strength with optimized UVA treatment increases to 263 MPa, which leads to fracture occurrence in the Mg alloy base plate. Eventually, it is experimentally demonstrated that robust MB3/AZ31 Mg alloy joints can be obtained by UVA process.     

Research on meta-action decomposition and meta-action unit modeling technology for electromechanical product

The current decomposition methods are not suitable for electromechanical product; the smallest decomposition units obtained by these methods are static parts or components, which cannot reflect the characteristics of electromechanical product that ‘action determines motion, and motion determines function'. Meta-action is the smallest action to realize the function of electromechanical product, and it is reasonable to regard meta-action as the smallest decomposition unit of electromechanical product. Meta-action unit is the smallest structural unit to ensure the normal operation of meta-action, and it is also the smallest carrier of electromechanical product quality characteristics. Meta-action unit modeling technology is the basis of other subsequent research, so it is necessary to study it. In this paper, detailed criteria for meta-action decomposition and meta-action unit separation are formulated, and the standardized structural model, symbolized conceptual model, and assembly model of meta-action unit are also studied, which provide a basis for mechanical, kinematic, and failure mechanism research of electromechanical product. A CNC (computer numerical control) machine tool made in China is taken as an example for meta-motion decomposition and meta-action unit modeling, and the results verify the applicability and correctness of the method proposed in this paper. The proposed method is also applicable to other types of electromechanical product.     

Charge photogeneration and recombination in ternary polymer solar cells based on compatible acceptors

The strategy of ternary blend is one of the most important approaches to enhance the power conversion efficiency (PCE) for polymer solar cells (PSCs). The present work prepared a new series of ternary PSCs, PBDB-T-2F:IT-4F:ITIC, based on the perspective of compatibility of non-fullerene molecule (ITIC) and its derivative (IT-4F) and studied the effect of the third component (ITIC) on the morphology and photoelectric conversion process of PBDB-T-2F:IT-4F solar cells. The results showed that surface roughness and phase scale of the PBDB-T-2F:IT-4F changed with the ITIC content, leading to variable morphology, optical, photophysical and electrical characteristics in ternary blend active layers. When the content of ITIC reached 20%, the ternary PSCs achieved the highest PCE (13.41%) among the PSCs. Morphology and optical spectroscopy studies showed that the enhanced performance of ternary device can be attributed to the morphology optimization of ternary active layer with the content of ITIC, and consequently the improved charge photogeneration processes. This work provided another way to achieve the high-performance ternary polymer solar cells via the combination of compatible non-fullerene molecules.

     

Deep-red iridium complex with alkyl-functionalized ligands for high-performance phosphorescent organic light-emitting diodes

Journal of Materials Science: Materials in Electronics - In this work, a novel deep-red (638 nm) iridium complex, Ir(bp3b)2(dend), is developed. This compound exhibits suitable physical...     

Discrete event-driven model predictive control for real-time work-in-process optimization in serial production systems

Advanced technologies (e.g., distributed sensors, RFID, and auto-identification) can gather processing information (e.g., system status, uncertain machine breakdown, and uncertain job demand) accurately and in real-time. By combining this transparent, detailed, and real-time production information with production system physical properties, an intelligent event-driven feedback control can be designed to reschedule the release plan of jobs in real-time without work-in-process (WIP) explosion. This controller should obtain the operational benefits of pull (e.g., Toyota’s Kanban system) and still develop a coherent planning structure (e.g., MRPII). This paper focuses on this purpose by constructing a discrete event-driven model predictive control (e-MPC) for real-time WIP (r-WIP) optimization. The discrete e-MPC addresses three key modelling problems of serial production systems: (1) establish a max-plus linear model to describe dynamic transition behaviors of serial production systems, (2) formulate a model-based event-driven production loss identification method to provide feedback signals for r-WIP optimization, and (3) design a discrete e-MPC to generate the optimal job release plan. Based on a case from an industrial sewing machine production plant, the advantages of the discrete e-MPC are compared with the other two r-WIP control strategies: Kanban and MRPII. The results show that the discrete e-MPC can rapidly and cost-effectively reconfigure production logic. It can decrease the r-WIP without deteriorating system throughput. The proposed e-MPC utilizes the available transparent sensor data to facilitate real-time production decisions. The effort is a step forward in smart manufacturing to achieve improved system responsiveness and efficiency.     

求解阻塞混流生产机器人制造单元调度问题的分支定界算法

针对阻塞混流生产机器人制造单元调度问题,为了同时优化机器人运行顺序和工件加工顺序,提出了分支定界算法。首先,定义机器人活动,将双排序转化为单排序;其次,构建顺序插入规则生成可行解;最后,依据顺序插入规则,设计了分支过程。通过计算随机生成算例,计算结果表明：工作站个数为3时,分支定界算法得到的目标函数值与CPLEX相同,但平均运行时间比CPLEX降低38.58%,证实了分支定界算法的有效性;工作站个数大于3时,与CPLEX相比,在同等时间内,有85.19%的算例搜索到更好解,因此,对于大规模情形,分支定界算法更有价值。     

Effects of the deep traps on the thermal‐stability property of CaAl2O4: Eu2+ phosphor

The thermal quenching properties and mechanisms of phosphors employed in white light emitting diodes (wLEDs) are critical for their commercial application. Here, we attempted to characterize the deep traps for capturing and releasing carriers to improve the thermal stability of the blue‐emitting CaAl₂O₄: Eu²⁺, Tm³⁺ phosphors. The enhanced thermal stability contributed to the introduction of traps has been demonstrated, and the mechanism of the transport process of carriers, has been explored in detail. In comparison with Eu²⁺ doped sample, the co‐doped Tm³⁺ samples bring more deep traps. The releasing of carriers in deep traps therefore sustains the luminescence with increasing temperature and compensates the thermal luminescence intensity loss. The results provide a theoretical basis and new field of view for exploring excellent thermal stability phosphors for wLEDs.     

Design of a compact planar wide band antenna family

A new family of compact planar wide band antennas is proposed. These simple and planar antennas have stable omnidirectional patterns and flat gain in the whole of bandwidth. Five types of these antennas are designed and simulated to clarify the ability of these introduced antenna family. Also, one of these antennas is fabricated and tested. The simulation and the measurement results are in good agreement. The measurement results show that this antenna works between 1.91 and 5.25 GHz (93.3% bandwidth) and it has a very compact dimensions. Also, the antenna analysis results show that the antenna center frequency and bandwidth can easily controlled by changing the scale factor and section factor, respectively. Finally, the antennas comparison results with the references verify the capability and power of them.