A Hybrid Model Method for Accurate Surface Deformation and Incision Based on FEM and PBD

In some simulations like virtual surgery, an accurate surface deformation method is needed. Many deformation methods focus on the whole model swing and twist. Few methods focus on surface deformation. For the surface deformation method, two necessary characteristics are needed: the accuracy and real-time performance. Some traditional methods, such as position-based dynamics (PBD) and mass-spring method (MSM), focus more on the real-time performance. Others like the finite element method (FEM) focus more on the accuracy. To balance these two characteristics, we propose a hybrid mesh deformation method for accurate surface deformation based on FEM and PBD. Firstly, we construct a hybrid mesh, which is composed of a coarse volume mesh and a fine surface mesh. Secondly, we implement FEM on coarse volume mesh and PBD on fine surface mesh, and the deformation of fine surface mesh is constrained by the displacement of the coarse volume mesh. Thirdly, we introduced a small incision process for our proposed method. Finally, we implemented our method on a simple deformation simulation and a small incision simulation. The result shows an accurate surface deformation performance by implementing our method. The incision effect shows the compatibility of our proposed method. In conclusion, our proposed method acquires a better trade-off between accuracy and real-time performance.

P084 MESH USE IN THE UNITED STATES: MESH TYPES AND THEIR INDICATIONS

Aim Synthetic non-absorbable mesh repair is considered standard of care for most hernias in the United States (US). The introduction of biologic absorbable mesh in the 2000’s has changed this practice and now novel synthetic absorbable and hybrid meshes are available. We aim to describe US trends of mesh use. Material and Methods We surveyed the Abdominal Core Health Quality Collaborative database for all repairs using mesh from 2012 to 2021. Mesh types and indications were analysed. Results Among 47,555 patients who underwent hernia repair with mesh, the majority were with synthetic non-absorbable meshes (96%). Absorbable mesh was placed in 2,039 (4%) patients and included biologic absorbable (893, 44%), synthetic absorbable (1,070, 52%), and hybrid (76, 4%) meshes. Synthetic non-absorbable mesh use was significantly predominant in all wound classes, including dirty/contaminated wounds (P < 0.01) [Figure 1]. Over time, we noted a trend toward lower incidence of absorbable and hybrid mesh use, from 18% to 2% (P < 0.01). Interestingly, we noted a relative increase in annual incidence of absorbable and hybrid mesh use in clean wounds, from 20% to 63% (P < 0.01) [Figure 2]. Figure 1Mesh type used in each wound classFigure 2Absorbable mesh use in clean vs. not clean wounds. Conclusions In the United States, synthetic non-absorbable meshes are commonly used during hernia repairs in dirty and contaminated fields. At the same time, there is a significant increase in the use of absorbable and hybrid meshes in the repair of hernias with clean wound classification. The costs and long-term outcomes of such surgeon choices have yet to be validated.

Investigation of Tire Rotating Modeling Techniques Using Computational Fluid Dynamics

Fuel efficiency becomes very important for new vehicles. Therefore, improving the aerodynamics of tires has started to receive increasing interest. While the experimental approaches are time consuming and costly, numerical methods have been employed to investigate the air flow around tires. Rotating boundary and contact patch are important challenges in the modeling of tire aerodynamics. Therefore, majority of the current modelling approaches are simplified by neglecting the tire deformation and contact patch. In this study, a baseline CFD model is created for a tire with contact patch. To generate mesh efficiently, a hybrid mesh, which combines hex elements and polyhedral elements, is used. Then, three modeling approaches (rotating wall, multiple reference frame and sliding mesh) are compared for the modeling of tire rotation. Additionally, three different tire designs are investigated, including smooth tire, grooved tire and grooved tire with open rim. The predicted results of the baseline model agree well with the measured data. Additionally, the hybrid mesh show to be efficient and to generate accurate results. The CFD model tends to over predict the drag of a rotating tire with contact patch. Sliding mesh approach generated more accurate predictions than the rotating wall and multiple reference frame approaches. For different tire designs, tire with open rim has the highest drag. It is believed that the methodology presented in this study will help in designing new tires with high aerodynamic performance.

Edge-Rich Interconnected Graphene Mesh Electrode with High Electrochemical Reactivity Applicable for Glucose Detection

The development of graphene structures with controlled edges is greatly desired for understanding heterogeneous electrochemical (EC) transfer and boosting EC applications of graphene-based electrodes. We herein report a facile, scalable, and robust method to produce graphene mesh (GM) electrodes with tailorable edge lengths. Specifically, the GMs were fabricated at 850 °C under a vacuum level of 0.6 Pa using catalytic nickel templates obtained based on a crack lithography. As the edge lengths of the GM electrodes increased from 5.48 to 24.04 m, their electron transfer rates linearly increased from 0.08 to 0.16 cm∙s−1, which are considerably greater than that (0.056 ± 0.007 cm∙s−1) of basal graphene structures (defined as zero edge length electrodes). To illustrate the EC sensing potentiality of the GM, a high-sensitivity glucose detection was conducted on the graphene/Ni hybrid mesh with the longest edge length. At a detection potential of 0.6 V, the edge-rich graphene/Ni hybrid mesh sensor exhibited a wide linear response range from 10.0 μM to 2.5 mM with a limit of detection of 1.8 μM and a high sensitivity of 1118.9 μA∙mM−1∙cm−2. Our findings suggest that edge-rich GMs can be valuable platforms in various graphene applications such as graphene-based EC sensors with controlled and improved performance.