POLYMER SEAL USE IN CENTRIFUGAL COMPRESSORS – TWO USERS’ EXPERIENCES OVER 15 YEARS

LectureFor over 20 years now, the efficiency and reliability of centrifugal compressors has been enhanced by the application of engineered thermoplastic materials to the eye, shaft, and balance piston labyrinth seals. Traditionally these seals have been manufactured from metallic materials (such as aluminum) and have required relatively large clearances for reliability reasons. By upgrading to carefully selected engineered thermoplastics the clearances can be reduced without sacrificing reliability. Polymer seals maintain their clearances even after typical start up rubs, whereas metallic seals open up during these rubs and are then open for the remainder of that run cycle (3, 4, 5 years or more). Polymer seal upgrades result in increased compressor efficiencies with the added benefit of easier installation. Of course whenever an upgrade of this type is first pursued the question of reliability and long term sustained success needs to be considered. Replacing a metallic component with a plastic one, in a service where running 24/7 for several years is imperative, needs to be carefully considered. Now that the seals have been successfully applied for over 20 years now, and individual seals have run for 9 years and more, we can evaluate the applicability of these materials to this type of application

POLYMER SEAL USE IN CENTRIFUGAL COMPRESSORS – TWO USERS’ EXPERIENCES OVER 15 YEARS

LectureFor over 20 years now, the efficiency and reliability of centrifugal compressors has been enhanced by the application of engineered thermoplastic materials to the eye, shaft, and balance piston labyrinth seals. Traditionally these seals have been manufactured from metallic materials (such as aluminum) and have required relatively large clearances for reliability reasons. By upgrading to carefully selected engineered thermoplastics the clearances can be reduced without sacrificing reliability. Polymer seals maintain their clearances even after typical start up rubs, whereas metallic seals open up during these rubs and are then open for the remainder of that run cycle (3, 4, 5 years or more). Polymer seal upgrades result in increased compressor efficiencies with the added benefit of easier installation. Of course whenever an upgrade of this type is first pursued the question of reliability and long term sustained success needs to be considered. Replacing a metallic component with a plastic one, in a service where running 24/7 for several years is imperative, needs to be carefully considered. Now that the seals have been successfully applied for over 20 years now, and individual seals have run for 9 years and more, we can evaluate the applicability of these materials to this type of application

Conjugated linoleic acid versus high-oleic acid sunflower oil: effects on energy metabolism, glucose tolerance, blood lipids, appetite and body composition in regularly exercising individuals

The aim of this study was to measure the effects of 12 weeks of conjugated linoleic acid (CLA) supplementation on body composition, RER, RMR, blood lipid profiles, insulin sensitivity and appetite in exercising, normal-weight persons. In this double-blind, randomised, controlled trial, sixty-two non-obese subjects (twenty-five men, thirty-seven women) received either 3.9 g/d CLA or 3.9 g high-oleic acid sunflower oil for 12 weeks. Prior to and after 12 weeks of supplementation, oral glucose tolerance, blood lipid concentrations, body composition (dual-energy X-ray absorptiometry and computerised tomography scans), RMR, resting and exercising RER and appetite were measured. There were no significant effects of CLA on body composition or distribution, RMR, RER or appetite. During the oral glucose tolerance tests, mean plasma insulin concentrations (0, 30, 120 min) were significantly lower (P= 0.04) in women who supplemented with CLA (24.3 (SD 9.7) to 20.4 (SD 8.5) microU/ml) compared to high-oleic acid sunflower oil control (23.7 (SD 9.8) to 26.0 (SD 8.8) microU/ml). Serum NEFA levels in response to oral glucose were attenuated in both men and women in the CLA (P=0.001) compared to control group. However, serum total cholesterol and LDL-cholesterol concentrations decreased in both groups and HDL-cholesterol concentrations decreased in women over 12 weeks (P=0.001, P=0.02, P=0.02, respectively). In conclusion, mixed-isomer CLA supplementation had a favourable effect on serum insulin and NEFA response to oral glucose in non-obese, regularly exercising women, but there were no CLA-specific effects on body composition, energy expenditure or appetite

BASEBALL PITCHING BIOMECHANICS AFTER SURGERY

Baseball pitchers with and without histories of elbow or shoulder surgery were tested with a 240 Hz automated 3D motion capture system. No differences were found between pitchers with history of UCL reconstruction and matched controls. Pitchers tested shortly after returning from UCL repair demonstrated reduced elbow extension, elbow velocity, and shoulder velocity compared to a control group, but it is unknown whether these few kinematic differences resolve with time. Pitchers with a history of SLAP repair produced less shoulder horizontal abduction, shoulder external rotation, and forward trunk tilt than matched controls. The Thoracic Outlet Syndrome case report demonstrated significantly more shoulder abduction after surgery. Thus the ability to return to normal pitching biomechanics after injury depends upon the type of surgery

Thermoplastic Labyrinth Seals In Centrifugal Compressors -15 Years Of Experiences

Case Studypg. 553-60

Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015

The third International Exercise-Associated Hyponatremia (EAH) Consensus Development Conference convened in Carlsbad, California in February 2015 with a panel of 17 international experts. The delegates represented 4 countries and 9 medical and scientific sub-specialties pertaining to athletic training, exercise physiology, sports medicine, water/sodium metabolism, and body fluid homeostasis. The primary goal of the panel was to review the existing data on EAH and update the 2008 Consensus Statement.1 This document serves to replace the second International EAH Consensus Development Conference Statement and launch an educational campaign designed to address the morbidity and mortality associated with a preventable and treatable fluid imbalance. The following statement is a summary of the data synthesized by the 2015 EAH Consensus Panel and represents an evolution of the most current knowledge on EAH. This document will summarize the most current information on the prevalence, etiology, diagnosis, treatment and prevention of EAH for medical personnel, athletes, athletic trainers, and the greater public. The EAH Consensus Panel strove to clearly articulate what we agreed upon, did not agree upon, and did not know, including minority viewpoints that were supported by clinical experience and experimental data. Further updates will be necessary to both: (1) remain current with our understanding and (2) critically assess the effectiveness of our present recommendations. Suggestions for future research and educational strategies to reduce the incidence and prevalence of EAH are provided at the end of the document as well as areas of controversy that remain in this topic. [excerpt

Longitudinal biomarkers in amyotrophic lateral sclerosis

OBJECTIVE: To investigate neurodegenerative and inflammatory biomarkers in people with amyotrophic lateral sclerosis (PALS), evaluate their predictive value for ALS progression rates, and assess their utility as pharmacodynamic biomarkers for monitoring treatment effects. METHODS: De-identified, longitudinal plasma, and cerebrospinal fluid (CSF) samples from PALS (n = 108; 85 with samples from \u3e /=2 visits) and controls without neurological disease (n = 41) were obtained from the Northeast ALS Consortium (NEALS) Biofluid Repository. Seventeen of 108 PALS had familial ALS, of whom 10 had C9orf72 mutations. Additional healthy control CSF samples (n = 35) were obtained from multiple sources. We stratified PALS into fast- and slow-progression subgroups using the ALS Functional Rating Scale-Revised change rate. We compared cytokines/chemokines and neurofilament (NF) levels between PALS and controls, among progression subgroups, and in those with C9orf72 mutations. RESULTS: We found significant elevations of cytokines, including MCP-1, IL-18, and neurofilaments (NFs), indicators of neurodegeneration, in PALS versus controls. Among PALS, these cytokines and NFs were significantly higher in fast-progression and C9orf72 mutation subgroups versus slow progressors. Analyte levels were generally stable over time, a key feature for monitoring treatment effects. We demonstrated that CSF/plasma neurofilament light chain (NFL) levels may predict disease progression, and stratification by NFL levels can enrich for more homogeneous patient groups. INTERPRETATION: Longitudinal stability of cytokines and NFs in PALS support their use for monitoring responses to immunomodulatory and neuroprotective treatments. NFs also have prognostic value for fast-progression patients and may be used to select similar patient subsets in clinical trials

Laser textured superhydrophobic surfaces and their applications for homogeneous spot deposition

This work reports the laser surface modification of 304S15 stainless steel to develop superhydrophobic properties and the subsequent application for homogeneous spot deposition. Superhydrophobic surfaces, with steady contact angle of ∼154° and contact angle hysteresis of ∼4°, are fabricated by direct laser texturing. In comparison with common pico-/femto-second lasers employed for this patterning, the nanosecond fiber laser used in this work is more cost-effective, compact and allows higher processing rates. The effect of laser power and scan line separation on surface wettability of textured surfaces are investigated and optimized fabrication parameters are given. Fluid flows and transportations of polystyrene (PS) nanoparticles suspension droplets on the processed surfaces and unprocessed wetting substrates are investigated. After evaporation is complete, the coffee-stain effect is observed on the untextured substrates but not on the superhydrophobic surfaces. Uniform deposition of PS particles on the laser textured surfaces is achieved and the deposited material is confined to smaller area