Electromagnetic Fields of Separable Space-Times

Carter derived the forms of the metric and the vector potentials of the space-times in which the relativistic Schrodinger equation for the motion of a charged particle separates. Here we show that on each `spheroidal' surface a rotation rate exists such that relative to those rotating axes the electric and magnetic fields are parallel and orthogonal to the spheroid which is thus an equipotential in those axes. All the finite Carter separable systems without magnetic monopoles or gravomagnetic NUT monopoles have the same gyromagnetic ratio as the Dirac electron.Comment: 9 pages; accepted for publication in Class. Quantum Gra

Application Of Dry Gas Seals On A High Pressur Hydrogen Recycle Compressor.

LecturePg. 3-8Maintenance and operation of high pressure seal oil systems on centrifugal compressors has been a major problem faced by refinery operators. This problem is intensified when sealing gases like hydrogen and mixtures of hydrocarbons. High pressures, low vilcosity, and solubility in oil pose unique problems in sealing with conventional wet seal oil systems. A breakthrough in sealing high pressure hydrogen with a gas seal design, which incorporates a natural breakdown of pressure across two seals without external pressure or flow controls is described. The retrofit has resulted in increased safety, low maintenance, and ease of operation; thus eliminating seal oil leakage and contamination. The recycle gas compressor that was retrofitted operated on 94 percent hydrogen at a discharge pressure of 12,896 kpa (1870 psig), a discharge temperature of 71°C (160°F) and an operating speed of 10,250 rpm. The problems that existed with the conventional seal oil system, the economics of the retrofit, the applicable dry seal design, process problems encountered during the retrofit and startup of the compressor and the successful resolution of these problems are covered. Operating data on the test bench and in field service are described and discussed

Rotor blade construction for circulation control aircraft

A circulation control aircraft rotor blade having a spanwise Coanda surface 16 and a plurality of spanwise extending flexible composite material panels 18 cooperating with the surface to define slots for the discharge of compressed air from within the blade with each panel having first flexure means 60 associated with screw adjustments 36 for establishing a slot opening preload and second flexure means 62 associated with screw adjustments 38 for establishing a slot maximum opening

Assessing and Ensuring GOES-R Magnetometer Accuracy

The GOES-R magnetometer accuracy requirement is 1.7 nanoteslas (nT). During quiet times (100 nT), accuracy is defined as absolute mean plus 3 sigma. During storms (300 nT), accuracy is defined as absolute mean plus 2 sigma. To achieve this, the sensor itself has better than 1 nT accuracy. Because zero offset and scale factor drift over time, it is also necessary to perform annual calibration maneuvers. To predict performance, we used covariance analysis and attempted to corroborate it with simulations. Although not perfect, the two generally agree and show the expected behaviors. With the annual calibration regimen, these predictions suggest that the magnetometers will meet their accuracy requirements

Assessing and Ensuring GOES-R Magnetometer Accuracy

The GOES-R magnetometer subsystem accuracy requirement is 1.7 nanoteslas (nT). During quiet times (100 nT), accuracy is defined as absolute mean plus 3 sigma. During storms (300 nT), accuracy is defined as absolute mean plus 2 sigma. Error comes both from outside the magnetometers, e.g. spacecraft fields and misalignments, as well as inside, e.g. zero offset and scale factor errors. Because zero offset and scale factor drift over time, it will be necessary to perform annual calibration maneuvers. To predict performance before launch, we have used Monte Carlo simulations and covariance analysis. Both behave as expected, and their accuracy predictions agree within 30%. With the proposed calibration regimen, both suggest that the GOES-R magnetometer subsystem will meet its accuracy requirements

Als3 is a Candida albicans invasin that binds to cadherins and induces endocytosis by host cells.

Candida albicans is the most common cause of hematogenously disseminated and oropharyngeal candidiasis. Both of these diseases are characterized by fungal invasion of host cells. Previously, we have found that C. albicans hyphae invade endothelial cells and oral epithelial cells in vitro by inducing their own endocytosis. Therefore, we set out to identify the fungal surface protein and host cell receptors that mediate this process. We found that the C. albicans Als3 is required for the organism to be endocytosed by human umbilical vein endothelial cells and two different human oral epithelial lines. Affinity purification experiments with wild-type and an als3delta/als3delta mutant strain of C. albicans demonstrated that Als3 was required for C. albicans to bind to multiple host cell surface proteins, including N-cadherin on endothelial cells and E-cadherin on oral epithelial cells. Furthermore, latex beads coated with the recombinant N-terminal portion of Als3 were endocytosed by Chinese hamster ovary cells expressing human N-cadherin or E-cadherin, whereas control beads coated with bovine serum albumin were not. Molecular modeling of the interactions of the N-terminal region of Als3 with the ectodomains of N-cadherin and E-cadherin indicated that the binding parameters of Als3 to either cadherin are similar to those of cadherin-cadherin binding. Therefore, Als3 is a fungal invasin that mimics host cell cadherins and induces endocytosis by binding to N-cadherin on endothelial cells and E-cadherin on oral epithelial cells. These results uncover the first known fungal invasin and provide evidence that C. albicans Als3 is a molecular mimic of human cadherins

Cleaning Turbomachinery Without Disassembly, Online And Offline.

LecturePg. 117-128Turbomachinery is designed for optimum aerodynamic and mechanical performance at given user conditions. Before shipment, this performance is usually verified on the OEM's test floor, based on specified design conditions. However, in operation, the gas composition can vary and include unanticipated solid and liquid ingestion into the turbomachinery, causing a buildup of foreign materials. The resulting fouling has an adverse effect on aerodynamic and mechanical performance of the unit. Fouling comes from external dust, dirt or dissolved matter, process materials, condensation and/or chemical reactions. Depending on the rate and composition of the deposits, the effect could range from a fast buildup, causing immediate shutdown of the unit due to high vibration and possible parts damage, to a slow buildup causing increased vibration and/or reduction in performance. An overview is presented of the cause, effect, and prevention of fouling on turbomachinery, with its main purpose to present tested and proven methods of cleaning turbomachinery. Presented are methods of online and offline (without disassembly) cleaning of multistage centrifugal compressors, axial compressors, and steam turbines. The operating environment will encompass hydrogen recycle gas, steam, and air. Methods include online cleaning using saturated steam, liquid spray and abrasive solids, and offline cleaning using acidized saturated steam for turbines and crank-washing for compressors

Enhancement of anti-DIII antibodies by the C3d derivative P28 results in lower viral titers and augments protection in mice

Antibodies generated against West Nile virus (WNV) during infection are essential for controlling dissemination. Recent studies have demonstrated that epitopes in all three domains of the flavivirus envelope protein (E) are targets for neutralizing antibodies, with determinants in domain III (DIII) eliciting antibodies with strong inhibitory properties. In order to increase the magnitude and quality of the antibody response against the WNV E protein, DNA vaccines with derivatives of the WNV E gene (full length E, truncated E, or DIII region, some in the context of the pre-membrane [prM] gene) were conjugated to the molecular adjuvant P28. The P28 region of the complement protein C3d is the minimum CR2-binding domain necessary for the adjuvant activity of C3d. Delivery of DNA-based vaccines by gene gun and intramuscular routes stimulated production of IgG antibodies against the WNV DIII region of the E protein. With the exception of the vaccine expressing prM/E given intramuscularly, only mice that received DNA vaccines by gene gun produced protective neutralizing antibody titers (FRNT80 titer >1/40). Correspondingly, mice vaccinated by the gene gun route were protected to a greater level from lethal WNV challenge. In general, mice vaccinated with P28-adjuvated vaccines produced higher IgG titers than mice vaccinated with non-adjuvanted vaccines

Magnetic Bearing Retrofit Of A High Speed, Eight Stage Coker Compressor.

LecturePg. 81-90The design, integration, and implementation of a successful project to retrofit a high speed, eight stage centrifugal compressor with magnetic bearings and gas face seals is presented. The application is removal of light gases from the top of a fractionating tower in a refinery coker unit. The justification and reasons for the selection of the coker compressor retrofitted with magnetic bearings are discussed. The technical aspects of design, rotordynamics and operation of the old oil bearing and seal design to the retrofitted magnetic bearing and gas face seal designs are compared. The tuning of the magnetic bearings is also discussed along with startup and operation of the compressor running on magnetic bearings. The significant challenge associated with retrofitting a compressor with magnetic bearings previously running on oil bearings is addressed from a design consideration and rotordynamics point of view. The development of assembly/disassembly techniques and manufacturing methods special to a magnetic bearing retrofit are described. Also presented is the logistics of meeting the short lead time and narrow turnaround window of 12 days at the user's facilit