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Knee and hip replacement have become increasingly routine, but a future challenge in artificial human bone is the skull. Whether through birth defect, accident, or disease, any breach of the [...]

A study was conducted to demonstrate the technique of comprehensive implant dentistry planning through integration of computer-aided design/computer-aided manufacturing (CAD-CAM) and cone-beam computed tomography (CBCT) data. The technique includes clinical treatment with guided surgery.

A study was conducted to examine the combined use of in-office and laboratory computer-aided design/computer-aided manufacturing (CAD/CAM) technologies that include making full-arch maxillary and mandibular digital impressions. It is concluded that digital restorative dentistry can now be applied to almost any restorative situation.

The application of computer-aided design/computer-aided manufacturing (CAD/CAM) in dentistry has evolved continually over 25 years, and material enhancements made in conjunction with this evolution have improved the precision and speed at which dentists can place high-quality restorations. An overview of the CEREC Acquisition Center with Bluecam system is also presented.

Modeling and simulation as well as new design tools are helping aerospace designers and engineers manage several degrees of freedom and evaluate how minor changes affect system performance. The article discusses advancements in design tools such as those from Space that help engineers reuse programs and Autodesk software that explains how various aspects of design fit together.

Dentists who use in-office CAD/CAM systems should have enough restorations per month to meet the approximately $2,000 lease payment for the device. A few-patients-per day/ high-fee practice model will not serve the needs of much of the public and is not the norm in U.S. dentistry. A CAD/CAM procedure is described for practices that wish to make this a routine service.

The impact that project complexity, student prior academic achievement, and quality of instructional materials might have on student academic achievement was studied during a required device physics course, in which technology computer-aided design (TCAD) tools were introduced to first-year graduate students. Preliminary analysis of student performance and project complexity showed that students who attempted the most complex projects had the lowest student academic achievement, despite there being no significant differences in prior academic achievement as measured by grades in the first exam in the course. Further analysis of student achievement data from other electrical engineering courses taught in a similar open laboratory format, for which enhanced instructional materials were developed, suggest that when well-developed learning resources are easily accessible to students, project complexity has no negative impact on student academic achievement and can sometimes enhance student academic performance. Cognitive load theory was used to explain why well-developed instructional tools, such as enhanced tutorials, can help students better learn or work with complex material. Index Terms--Cognitive load theory, device physics, education, graduate students, technical computer-aided design (TCAD).

A fully scalable and SPICE compatible wideband model of on-chip interconnects valid up to 110 GHz is presented in this paper. The series branches of the proposed multisegment model consist of an RL ladder network to capture the skin and proximity effects, as well as the substrate skin effect. Their values are obtained from a technique based on a modified effective loop inductance approach and complex image method. A CG network is used in the shunt branches of the model, which accounts for capacitive coupling through the oxide and substrate loss due to the electrical field, as well as the impact of dummy metal fills. The values of these elements are determined by analytical and semiempirical formulas. The model is validated by a full-wave electromagnetic field solver, as well as measurements. The simulated S-parameters of the model agree well with the measured S-parameters of on-chip interconnects with different widths and lengths over a wide frequency range from dc up to 110 GHz. Index Terms--Model, on-chip interconnects, scalable, SPICE compatible, wideband.

This paper presents a direct-analysis technique for transistors with a long-finger structure. The analysis technique is an incorporated simulation between the finite-difference time-domain electromagnetic (EM) and semiconductor device simulations. The co-simulation method can consider various EM couplings and phase shifts on finger electrodes of transistors. The method was applied for InGaP/GaAs HBTs with various finger lengths to investigate gain degradation characteristics as a function of the finger length. As the first step, circuit simulations were done instead of a semiconductor device simulation using SPICE models of the HBT. Both large- and small-signal equivalent-circuit parameters were extracted by measurements to estimate nonlinear and linear characteristics, respectively. Using the extracted small-signal parameters, the gain degradation was estimated. The co-simulation results showed the same tendency as measurement results. Additionally, it was numerically shown that a resistive loss was mainly affected for the gain degradation from a comparison between gold and lossless electrodes. Index Terms--Co-simulation, device simulation, finite difference time domain (FDTD), HBT, long-finger transistor, technology computer-aided design (TCAD).

This paper presents a computer-aided design (CAD) module able to analyze different manufacturing configurations of tubes used in mechanical assemblies, such as exhaust system manifolds. It can be included in the knowledge-based expert system category and has been implemented into a CAD platform as a dedicated module able to take into account manufacturing requirements related to tube bending, hydroforming, and cutting. The expert's knowledge, in terms of set of rules and criteria, has been implemented by means of the automation tools of CATIAV5R10 according to the so-called methodological formal approach. The resulting module is able to join different tubes starting from their geometrical models, obtaining a set of manufacturing alternatives. Each of them is verified with respect to collisions with a bending machine and also in terms of hydroforming process feasibility. Only those solutions that satisfy these checks are accepted as feasible and ranked according to three evaluation criteria related to manufacturing cost and easiness. The system is completely automatic and able to analyze more than 100 different configurations in Keywords: design to manufacturing, knowledge based expert system, tube bending, tube hydroforming, CAE

Gear hobbing, as any cutting process based on the rolling principle, is a signally multi-parametric and complicated gear fabrication method. Although a variety of simulating methods has been proposed, each of them somehow reduces the actual three-dimensional (3D) process to planar models, primarily for simplification reasons. The paper describes an effective and factual simulation of gear hobbing, based on virtual kinematics of solid models representing the cutting tool and the work gear. The selected approach, in contrast to former modeling efforts, is primitively realistic, since the produced gear and chips geometry are normal results of successive penetrations and material removal of cutting teeth into a solid cutting piece. The algorithm has been developed and embedded in a commercial CAD environment, by exploiting its modeling and graphics capabilities. To generate the produced chip and gear volumes, the hobbing kinematics is directly applied in one 3D gear gap. The cutting surface of each generating position (successive cutting teeth) formulates a 3D spatial surface, which bounds its penetrating volume into the workpiece. This surface is produced combining the relative rotations and displacements of the two engaged parts (hob and work gear). Such 3D surface 'paths' are used to split the subjected volume, creating concurrently the chip and the remaining work gear solid geometries. This algorithm is supported by a universal and modular code as well as by a user friendly graphical interface, for pre- and postprocessing user interactions. The resulting 3D data allow the effective utilization for further research such as prediction of the cutting forces course, tool stresses, and wear development as well as the optimization of the gear hobbing process. [DOI: 10.1115/1.2738947] Keywords: gear hobbing, simulation, 3D-Modeling, CAD

The design and fabrication of single-layer nano-scale SQUIDs by using computer-aided-design software and focused-ion-beam techniques to realize sub-micrometer superconducting structures is presented.

Use of computer aided design and computer aided manufacturing technology for dental implants.

The article discusses about the use of finite elements method (FEM) software in order to help lecturer to teach design of electrical machines. Nowadays, lecturers have less and less time to teach the design of electrical machines. Special tools based on FEM can help them in this task. For the past years, such tools needing sophisticated environments have been realized for designers in industry. Assuming minimum equipment, requirements and guidelines for the realization of a specific tool are presented. Index Terms--Design, electrical machines, finite elements method (FEM).

Omega-field-effect transistor (OFET) devices, which feature an undoped cylindrical channel uniformly surrounded by a gate electrode, are investigated. The study is based on TCAD device simulations of OFETs with gate lengths ranging between 10 and 130 nm and radii ranging between 1 and 65 nm.

LMAG-2D is an educational Finite-Element Analysis software package with CAD/CAE technology used to teach the finite element method to undergraduate and graduate students of electrical engineering. A user-friendly interface encapsulates the technical complexity of the method, allowing students and professionals, even in their first contact with this methodology, to appreciate its relevance to practical problems. LMAG-2D can be used to simulate complex two dimensional 'real-world' electrostatic, magnetostatic and electrokinetic models, with planar and axial symmetries. Linear and nonlinear phenomena can also be simulated.

A hybrid technique suitable for the space-time analysis of the transient spurious emission from microstrip interconnects is presented. The proposed technique requires the preliminary evaluation of the surface current excited on the microstrip interconnecting lines by means of a transmission line model accounting for dispersive effects. The radiated field is then computed in the frequency domain by applying the saddle-point asymptotic technique to the integral expression of the electric field involving the dyadic Green's function. The transient signals excited along the interconnects, and the corresponding radiated field, are finally determined by using the IFFT. Radiation mechanisms are investigated, and the influence of the structure's electrical and geometrical parameters is discussed.

Glaize and Bros. (GB) utilized computer-aided design (CAD)/computer-aided manufacturing (CAM) flexible manufacturing systems to develop efficient management strategies for manufacturing operations. The manufacturing process technology was used to develop a simulation model for manufacturing operations that improved GB's in line capacity by 10% with minimal increase on labor and capital. The simulation model also provided data for future improvements of manufacturing capacity.