Finite element analysis of porously punched prosthetic short stem virtually designed for simulative uncemented hip arthroplasty

Background: There is no universal hip implant suitably fills all femoral types, whether prostheses of porous short-stem suitable for Hip Arthroplasty is to be measured scientifically. Methods: Ten specimens of femurs scanned by CT were input onto Mimics to rebuild 3D models; their *stl format dataset were imported into Geomagic-Studio for simulative osteotomy; the generated *.igs dataset were interacted by UG to fit solid models; the prosthesis were obtained by the same way from patients, and bored by punching bears designed by Pro-E virtually; cements between femora and prosthesis were extracted by deleting prosthesis; in HyperMesh, all compartments were assembled onto four artificial joint style as: (a) cemented long-stem prosthesis; (b) porous long-stem prosthesis; (c) cemented short-stem prosthesis; (d) porous short-stem prosthesis. Then, these numerical models of Finite Element Analysis were exported to AnSys for numerical solution. Results: Observed whatever from femur or prosthesis or combinational femora-prostheses, “Kruskal-Wallis” value p > 0.05 demonstrates that displacement of (d) ≈ (a) ≈ (b) ≈ (c) shows nothing different significantly by comparison with 600 N load. If stresses are tested upon prosthesis, (d) ≈ (a) ≈ (b) ≈ (c) is also displayed; if upon femora, (d) ≈ (a) ≈ (b) < (c) is suggested; if upon integral joint, (d) ≈ (a) < (b) < (c) is presented. Conclusions: Mechanically, these four sorts of artificial joint replacement are stabilized in quantity. Cemented short-stem prostheses present the biggest stress, while porous short-stem & cemented long-stem designs are equivalently better than porous long-stem prostheses and alternatives for femoral-head replacement. The preferred design of those two depends on clinical conditions. The cemented long-stem is favorable for inactive elders with osteoporosis, and porously punched cementless short-stem design is suitable for patients with osteoporosis, while the porously punched cementless short-stem is favorable for those with a cement allergy. Clinically, the strength of this study is to enable preoperative strategy to provide acute correction and decrease procedure time

FaceChain-SuDe: Building Derived Class to Inherit Category Attributes for One-shot Subject-Driven Generation

Subject-driven generation has garnered significant interest recently due to its ability to personalize text-to-image generation. Typical works focus on learning the new subject's private attributes. However, an important fact has not been taken seriously that a subject is not an isolated new concept but should be a specialization of a certain category in the pre-trained model. This results in the subject failing to comprehensively inherit the attributes in its category, causing poor attribute-related generations. In this paper, motivated by object-oriented programming, we model the subject as a derived class whose base class is its semantic category. This modeling enables the subject to inherit public attributes from its category while learning its private attributes from the user-provided example. Specifically, we propose a plug-and-play method, Subject-Derived regularization (SuDe). It constructs the base-derived class modeling by constraining the subject-driven generated images to semantically belong to the subject's category. Extensive experiments under three baselines and two backbones on various subjects show that our SuDe enables imaginative attribute-related generations while maintaining subject fidelity. Codes will be open sourced soon at FaceChain (https://github.com/modelscope/facechain).Comment: accepted by CVPR202

Out-of-Candidate Rectification for Weakly Supervised Semantic Segmentation

Weakly supervised semantic segmentation is typically inspired by class activation maps, which serve as pseudo masks with class-discriminative regions highlighted. Although tremendous efforts have been made to recall precise and complete locations for each class, existing methods still commonly suffer from the unsolicited Out-of-Candidate (OC) error predictions that not belongs to the label candidates, which could be avoidable since the contradiction with image-level class tags is easy to be detected. In this paper, we develop a group ranking-based Out-of-Candidate Rectification (OCR) mechanism in a plug-and-play fashion. Firstly, we adaptively split the semantic categories into In-Candidate (IC) and OC groups for each OC pixel according to their prior annotation correlation and posterior prediction correlation. Then, we derive a differentiable rectification loss to force OC pixels to shift to the IC group. Incorporating our OCR with seminal baselines (e.g., AffinityNet, SEAM, MCTformer), we can achieve remarkable performance gains on both Pascal VOC (+3.2%, +3.3%, +0.8% mIoU) and MS COCO (+1.0%, +1.3%, +0.5% mIoU) datasets with negligible extra training overhead, which justifies the effectiveness and generality of our OCR.Comment: Accepted to CVPR202

3D Microscopic Simulation of Mediator Supercapacitors

Supercapacitors (SCs) can reach a high specific energy (25-50 Wh/kg) by doping mediators in electrolyte contained in porous electrode structure. Mediators in electrolyte can be considered as redox materials to provide pseudocapacitance and to increase the conductivity of electrolyte. However, the charge/discharge behaviors of the mediators with respect to current and voltage are difficult to be resolved because of the complicated structure and charge/discharge kinetics of the electrode materials. In this work, a 3D microscopic model is established to investigate the roles of different components, especially mediators in charge/discharge processes. The microscopic model (Figure 1) is solved using COMSOL Multiphysics. Activated carbon, carbon fibers, mediators and polymer electrolyte are explicitly represented in this model. The simulation describes the process after applying a voltage on the mediator SC. During charging, electric current flows into the mediators at positive electrode and flows out from the mediators at negative electrode. The charge rate at electrical double layers is much faster than the charge rate for the mediator domains due to different charge storage mechanisms. The mediators can only store the charges at the certain potential range. With the increase of the mediator capacitance, the time to reach a stable state increases. The mediators can also affect the stable potential of the electrolyte. As such, the model can be used to design the composition of the mediator SCs and predict the effect of mediators on the performance of the mediator SCs. In addition, the information regarding the stable electrolyte potential vs. mediator capacitance can be used to choose the electrolyte with specific potential windows to avoid electrolyte degradation at electrode/electrolyte interface. Figure

Effect of Metal Complex Mediators on the Performance of Mediator Supercapacitor

Demand of electrical energy storages is increasing quickly with market expansion of cell phones, electrical vehicles, and stationary energy storage. Supercapacitor is an alternative choice of rechargeable batteries because of their low cost for fabrication and maintenance, high cycle life, high charge rate, and high specific power. Using mediators to enhance the performance of the carbon materials based supercapacitors is more effective than using conductive polymer or metal oxide materials. In this study, we improved the performance using metal complex mediators. Several different mediators were synthesized and compared in this work. The active electrode material consisted of 10% mediator, 90% high specific surface area active carbon (AC). An EDLC made by AC only was also fabricated as a reference. To qualify the industrial requirements, current collector, electrolyte and separator are all commercial. The prototypes were fabricated in the glove box and sealed under vacuum. The calculation of specific energy (SE) was based on total mass of both electrodes and cyclic voltammetry (CV) curves and glvanostatic charge/discharge curves (GCDs). Typical CVs were shown in Figure 1. The mediator supercapacitor exhibited high energy densities (˃40 Wh kg -1 ), high charge/discharge efficiency (˃99%) and high reversibility (˃90% after 10000 cycles). The effect of the rare earth and transition metals on the effectiveness of the mediators is investigated. As shown in Table 1, for mediators containing rare earth metals, Pr, La, Y are more effective than Ho. For mediators containing transition metals, Mn, Fe, and Co are more effective than Zn. The authors explain the phenomenon with the notions of molecular configurations, electronic structures, and interactions between charged mediators. Figure

Mediator Effects on Solid-State Mediator Doped Polymer Electrolyte Membrane

Electrolyte and separator are two vital components in supercapacitors. High safety is one of the major advantages of polymer electrolyte, which means, even in extreme environment or during faulty, polymer electrolyte will not release any harmful gas or liquid. Mediators are a pair of compounds which can reciprocal transform by losing and gaining electrons. Thus, doping mediators in polymer electrolyte will improve the electronic conductivity. Use of the mediator doped electrolytes in the electrode matrix will benefit the transport process in supercapacitors. However, these electrolytes should not be used in the separators. Polyvinylidene fluoride (PVDF) and lithium trifluoromethanesulfonate (LiTFS) was selected as polymer electrolyte. One mediator couple are potassium ferrocyanide (K 3 Fe(CN) 6 ) and potassium ferricyanide (K 4 Fe(CN) 6 ). Another couple are iodine (I 2 ) and sodium iodide (NaI). Conductivity of the membranes were measured with an device as shown in Figure 1. Results of electronic conductivity versus the concentration of mediators are given in Figure 2 and results of ionic conductivity versus the concentration of mediators are given in Figure 3. Electronic conductivity of membranes is enhanced from 10 -7 S/cm level to 10 -4 S/cm level by increasing the concentration of mediators from 0% to 5%. In the I 2 /NaI mediator doped membrane the electronic conductivity continuously increase with increasing the concentration above 5%. However, in the K 3 Fe(CN) 6 / K 4 Fe(CN) 6 . doped membrane the electronic conductivity is a constant above 5%. Ionic conductivity of membranes is stayed on 10 -2 S/cm level. The authors use the electron exchange mechanism and site percolation theory to explain the phenomenon. Figure

Development of structural supercapacitors with epoxy based adhesive polymer electrolyte

•An adhesive polymer electrolyte was prepared using PVDF, LiTf, and epoxy.•High ionic conductivity (>10−2 S cm−1) of PVDF/LiTf/epoxy was achieved.•Structural SCs using PVDF/LiTf/epoxy were fabricated with a vacuum bagging method.•In-situ electrochemical tests of the structural SCs were conducted. Epoxy based adhesive polymer electrolyte was prepared using polyvinylidene fluoride, lithium triflate, and epoxy. The effect of the composition of the adhesive polymer electrolyte on the ionic conductivity, viscosity, and tension strength was investigated. The ionic conductivity of an adhesive polymer electrolyte could reach the order of magnitude of 10−2 S cm−1. Structural supercapacitors with epoxy based adhesive polymer electrolyte were fabricated using a vacuum bagging method. The structural supercapacitors showed excellent electrochemical performance and acceptable mechanical strength simultaneously. The maximum specific energy was 2.64 Wh kg−1 and the ultimate tensile strength was 80 MPa. The capacitance retention of the structural SC was 84% and the columbic efficiency was above 95% after 5000 cycles. The response of electrochemical performance of the structural supercapacitors to in-plane tensile stress was studied. Before fracture, both the specific power and the specific energy increased slightly with increasing the stress level. A high conductive adhesive polymer electrolyte based structural supercapacitor. [Display omitted

Pseudocapacitor Based on Mediators Attached to CNTs

Recent study has demonstrated that addition of metal cyanide mediators or redox species into polymer electrolytes can effectively increase the specific enrgy and power of supercapacitor to the levels of 30 Wh/kg at 1 kW/kg or 15 Wh/kg at 15 kW/kg. In order to further enhance the performance of the supercapacitors, the mediator-containg polymer electrolyte was absobed into a matrix of carbon nanotubes (CNTs) grown on carbon paper or metal foils (Fig. 1). A CVD process is optimized to ordered carbon nanotubes on the substrates with capability of controlling the ratio of semiconductor versus conductor CNTs. The electrode materials were used to fabricate full-cell supercapacitors with symetric or asymetric configurations. Three-electrode and full-cell electrochemical measurements were conducted to evaluate the performances of the supercapacitors. Galvanostatic charge-discharge results indicate that the specific energy was 39 Wh/kg at 1 kW/kg or 18 Wh/kg at 15 kW/kg. The cyclic voltammtry data show that the pseudocapacitors behave similarly as an electric double layer capacitor (EDLC). Self-discharge of the pseudocapacitors was also evaluated using open circuit voltage monitoring method. The self-discharge resistance was evaluated using an equivalent circuit model. The analytical results indicate that the self-discharge was improved by at least 1.5 times showing the effect of absorption of mediators into the CNT matrix. Figure