The cooperative effort is described of equipment manufacturers, the process plant designer and the ultimate user to specify and design a compressor system that was driven by a 10,500 horsepower induction motor that was controlled by a variable frequency drive (VFD) system. A design methodology is presented which avoids the potential of VFD system harmonics from coinciding with system mechanical...

There are different dynamic or static test methodologies for evaluating the shear and torsional moduli of wood. A preferred method is nondestructive, accurate, and standard. However, dynamic methods using conventional devices previously suggested for determining the orthotropic shear moduli of wood are neither accurate nor standard. Thus, a reliable method for evaluating the torsional modulus o...

Torsional vibration problems continue to occur in reciprocating engine and compressor installations. This is due in part to the fact that reciprocating equipment can produce significantly more torsional excitation than rotating machinery such as turbines, centrifugal compressors, and centrifugal pumps. The purpose of this tutorial is to raise awareness of torsional vibration problems that can o...

BACKGROUND Because of the slow pharmacokinetics of subcutaneous (SC) insulin, avoiding postprandial hyperglycemia has been a major challenge for an artificial pancreas (AP) using SC insulin without a meal announcement. METHODS A semiautomated AP with Technosphere® Insulin (TI; MannKind Corporation, Valencia, CA) was designed to combine pulmonary and SC insulin. Manual inhalation of 10 U ultra...

Based on a model with three-degree-of-freedom, the nonlinear coupled axial-torsional vibration of drill string is numerically studied considering modified contact bit-rock interaction. The effects driving angular velocities, nominal drilling pressures, and formation stiffness response are discussed. simulation results show that can be periodic, quasi-periodic or chaotic motion variation system ...

fabrication, characterization and application of micro-/nano-rods/wires are among the hottest topics in materials science and applied physics. micro-/nano-rod-based structures and devices are developed for a wide-ranging use in various fields of micro-/nanoscience (e.g. biology, electronics, medicine, optics, optoelectronics, photonics and sensors). it is well known that the structure and prope...

Recognition of cell-surface sialyldisaccharides by influenza A hemagglutinin (HA) triggers the infection process of influenza. The changes in glycosidic torsional linkage and the receptor conformations may alter the binding specificity of HAs to the sialylglycans. In this study, 10-ns molecular dynamics simulations were carried out to examine the structural and dynamic behavior of the HAs bound...

Photons carry linear momentum and spin angular momentum when circularly or elliptically polarized. During light-matter interaction, transfer of linear momentum leads to optical forces, whereas transfer of angular momentum induces optical torque. Optical forces including radiation pressure and gradient forces have long been used in optical tweezers and laser cooling. In nanophotonic devices, opt...

The intracellular polymerization of deoxy-sickle cell hemoglobin (HbS) has been identified as the main cause of sickle cell disease. Therefore, the material properties and biomechanical behavior of polymerized HbS fibers is a topic of intense research interest. A solvent-free coarse-grain molecular dynamics (CGMD) model is developed to represent a single hemoglobin fiber as four tightly bonded ...

Turbine-generator shafts are often subjected to a complex transient torsional loading. Such transient torques may initiate and propagate a circumferential crack in the shafts. Mode III crack growth in turbo-generator shafts often results in a fracture surface morphology resembling a factory roof. The interaction of the mutual fracture surfaces results in a pressure and a frictional stress field...