In spite of the widespread use of tablets, the theoretical understanding of the tableting process has been limited. During the last decades considerable research has been done in the field of powder technology and compaction. A survey of the literature and compression equations reveals many studies on the characterization of powder properties, most of which relate to volume reduction under pressure, i.e., to the compressibility of the powder bed. For practical purposes, however, it is also important to know the compactibility of a powder bed, i.e., the ability of a powdered material to be compressed into a compact of specified strength. This strength has to be defined, e.g., as radial tensile strength or deformation hardness. Thus the first part of this review comprises the theory of powder compression of individual substances, compression parameters, compression equations, and mechanical properties of compacts, including compact strength tests and compact hardness tests.

Fundamentals of Powder Compression. I. The Compactibility and Compressibility of Pharmaceutical Powders

Bone size and mechanics at the femoral diaphysis across age and sex

An intramedullary gradual elongation nail (Albizzia) capable of fulfilling the function of traditional intramedullary nails while providing the gradual, controlled distraction of an external fixator was designed for progressive lengthening of lower limbs. In this study, the biomechanics of the gradual elongation nail were compared with several intramedullary nails: Grosse & Kempf, Russell-Taylor, AO, and Laffay. Bending stiffness, torsional stiffness, ultimate bending strength, and torsional strength were determined using the American Society for Testing and Materials standard F383-73 as a guide. The results show that in unextended and elongated conditions, the gradual elongation nail has torsional stiffness (1-5 Nm2) comparable with the AO nail (2 Nm2) and bending stiffness (41-89 Nm2), ultimate bending (246 Nm), and torsional (28-37 Nm) strengths within the ranges obtained for other intramedullary nails (27-105 Nm2, 167-298 Nm, and 2-100 Nm, respectively). Additionally, the low torque required to lengthen the device under a 500 N load (3 Nm) and the low longitudinal stiffness because of the active dynamization system with bimodal load deformation characteristics (80-120 N/mm initial, 600-800 N/mm secondary) produce a device with almost no torsional and longitudinal stress shielding. From a biomechanical point of view, this single, completely implantable device is a safe, viable, and efficacious alternative to external fixation for progressive lengthening of lower limbs.

Mechanical characterization of a totally intramedullary gradual elongation nail

A new model for the prediction of cutting forces in micro-end-milling operations

Resilience is of great importance for teams working in complex and unstable environments. Team resilience is the ability of the teams/groups to bounce back and sustain in the facade of adverse cond...

Team Resilience: Scale Development and Validation:

Tension and compression statically indeterminate force systems - tension and compression thin-walled pressure vessels direct shear stresses torsion shearing force and bending moment centroids, moments of inertia and products of inertia of plane areas stresses in beams elastic deflection of beams - double-integration method elastic deflection of beams - method of singularity functions statically indeterminate elastic beams special topics in elastic beam theory plastic deformation of beams columns strain energy methods combined stresses members subject to combined loadings - theories of failure.

William Arthur Nash

Papers

Schaum's Outline of Theory and Problems of Strength of Materials