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Principles of Energy Conversion
Published in Hamid A. Toliyat, Gerald B. Kliman, Handbook of Electric Motors, 2018
Hamid A. Toliyat, Gerald B. Kliman
Squirrel-cage rotors are manufactured in one of three basic cage design configurations, that is: die-cast aluminum, fabricated aluminum, or fabricated copper or copper alloy. Manufacturers are limited to maximum die-cast rotor dimensions depending upon the capability of their die-casting equipment. Larger rotors must be fabricated. In some cases, fabricated rotors can be provided instead of die-cast rotors. Fabricated copper rotors are frequently used in applications involving severe starting requirements, above normal torque, or higher than normal efficiency values. If a specific cage construction or material is required, it must be specified. The bars of fabricated copper rotors are brazed to the shorting rings. In some environments, the use of phosphorus-free brazing materials may be preferred. If so, it must be specified.
Methodology for Supply Chain Security
Published in Arthur G. Arway, Supply Chain Security, 2013
Classification should categorize levels from high to low: A, B, or C; high, medium, or low; red, yellow, or green; or whatever is more easily understood for your operation. No matter the label, the intent is to understand the security need and apply the appropriate response and program. An example of the usefulness of classifying a location or operation would be the security program for the installation and use of a high-value cage. Generally, high-value cages are used to isolate and control the access to high-value or high-risk materials or goods from the general work force. They are kept under strict control with CCTV and other documentation procedures, with limited and controlled access by select people. The cages are mostly of durable-gauge steel or metal-wire-mesh sides, extended to the ceiling or topped with wire roofs, covered by CCTV from various angles, having controlled access at doorways or gates, and alarmed in some manner.
Reduction and Fixation of Sacroiliac joint Dislocation by the Combined Use of S1 Pedicle Screws and an Iliac Rod
Published in Kai-Uwe Lewandrowski, Donald L. Wise, Debra J. Trantolo, Michael J. Yaszemski, Augustus A. White, Advances in Spinal Fusion, 2003
Kai-Uwe Lewandrowski, Donald L. Wise, Debra J. Trantolo, Michael J. Yaszemski, Augustus A. White
Interbody fixation is achieved by using interbody devices termed cages. The development of interbody cages derived from the hypothesis that cages offer theoretical biomechanical advantages over other types of internal fixation [41,42]: they provide initial structural support in the axial plane; they provide distraction of the spine motion segment and restore disc height and sagittal balance; distraction allows for clearance of the intervertebral foramina in cases of foraminal stenosis; favorable conditions exist for an interbody fusion to occur because the anterior column is expected to bear some 80% of the compressive stresses acting on a motion segment. According to their shape, two types of cages are classified [43]: cylindrical or conical cages (threaded cages) and box-shaped or rectangular cages (nonthreaded cages). Threaded cages are inserted by a threaded device after the vertebral endplates have been prepared with a reamer. Nonthreaded cages are placed after removal of the endplate cartilage. Interbody cages can be inserted through an anterior or posterior surgical approach. Whereas the anterior approach is mandatory in the cervical spine, either approach is feasible in the lumbar spine (ALIF: anterior lumbar interbody fusion; PLIF: posterior lumbar interbody fusion; TLIF: transforaminal lumbar interbody fusion) [44-46]. Doubts have been raised whether a thorough clearance of soft tissues and cartilage can actually be achieved
Lubrication, Flow Visualization, and Multiphase CFD Modeling of Ball Bearing Cage
Published in Tribology Transactions, 2022
Saeed Aamer, Farshid Sadeghi, Thomas Russell, Wyatt Peterson, Andreas Meinel, Hannes Grillenberger
Bearings are critical components in industrial machinery, ensuring smooth and long-term operation by providing relative motion between sliding components. Angular contact ball bearings (ACBBs) are a popular class of bearings that can concurrently handle significant axial and radial loads, making them more suitable for use in machinery where supporting axial and radial loads is critical (e.g., gearboxes, machine tool spindles, and differentials) (1–4). ACBBs are able to operate under high loads (5, 6) with long operating life. ACBB cages vary greatly in design, material, and manufacturing processes to meet the needs of specific applications. Cage designs include stamped, injection-molded, and machined cages. A bearing cage is primarily used to ensure even spacing between rolling elements (6), which in turn allows for even distribution of load. However, cages also play an important role in lubricant distribution within a bearing, which is crucial to its performance and life (7).
Finite element study on the influence of pore size and structure on stress shielding effect of additive manufactured spinal cage
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Vijay Kumar Meena, Parveen Kalra, Ravindra Kumar Sinha
Spinal injuries and spinal disorders are becoming increasingly common ailments in modern life. One of the most common diseases/ailments is Degenerative Disc Disease, popularly known as DDD (Pannell et al. 2015). The cure involves surgical procedures of degenerated disc and insertion of appropriate implants, namely spinal cages between the vertebrae. Titanium alloy (Ti6Al4V) is the preferred choice for spinal cages due to its high tensile strength, good biocompatibility, good fatigue strength, and corrosion resistance (Ramakrishna et al. 2001). These spinal cages are generally made of solid dense metals/polymers e.g. titanium, Carbon Fiber Reinforced PEEK, etc. Young’s modulus of these materials is much higher than human bone Young’s modulus. The elastic modulus of bone varies between 1 and 20 GPa whereas the elastic modulus of titanium is 110 GPa. Due to this vast difference in elastic modulus, the loads are not transferred from the implant to adjacent bone tissue, resulting in stress shielding between the host bone and the implant. This leads to adaptive resorption of bone tissue and a decrease in mechanical rigidity of the bone as per Wolff’s law (Chen et al. 2010). Similarly, with reduced stress shielding, bone tissues are known to generate deposition of new bone, which increases mechanical rigidity (Stock 2018). Also, the smooth and shiny surface of solid metal implants makes it difficult to integrate with the host bone. This causes amyotrophy and osteonecrosis of bones around the implants, loosening of the implant, distortion of bones, etc (Haibo et al. 2012).
Comparison of dynamic response of three TLIF techniques on the fused and adjacent segments under vibration
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
The Intact L1–L5 spine FE model was modified to simulate three different TLIF techniques (a unilateral standard cage, a single crescent-shaped cage, and bilateral standard cages) in this paper. The technical difference lies in the number and shape of cages. In this paper, two kinds of cages are used: standard cage (L18 × W10 × H9 mm) and crescent-shaped cage (L28 ×W10 × H9 mm). The specific three-dimensional size of the cage is determined by the measurement results of the L4–L5 intervertebral disc in cadavers. The reason for choosing L4–L5 is that the prevalence of L4–L5 is higher than that of other intervertebral discs (Cheung et al. 2009; Ruberte et al. 2009). The standard cage is a cuboid structure, and its placement options in this study are unilateral and bilateral. Unilateral cage placement simulation: cage was inserted at the center of the disc space by an oblique approach through the annulus incision. Bilateral cages were implanted in the same way as the unilateral cage, and two standard cages are symmetric to the midline of the disc space. The crescent-shaped cage was placed at the center of the intervertebral disc space in the same way as the unilateral cage and centered on the central sagittal plane. The currently built fusion models with three different TLIF techniques are shown in Figure 2, and the material properties and element types of the corresponding implants are listed in Table 1.