Influence Of Gas Seals On Rotor Stability Of A High Speed Hydrogen Recycle Compressor.

LecturePg. 9-18A gas seal retrofit project for a 2800 hp, 10200 rpm, five-stage hydrogen recycle compressor is described. This barrel-type compressor operates with a 1205 psia suction pressure and 1490 psia discharge pressure. The unit is directly driven by a steam turbine through a continuously lubricated gear-type coupling. The gas seal retrofit project was initiated as a solution to a rotordynamic instability problem experienced on the compressor. The rotordynamic analysis showed that the rotor system stability would be improved with the gas seals. The other advantages of gas seals were considered as secondary to the stability improvements

Assessing Rotor Stability Using Practical Test Procedures.

LecturePg. 151-160Perturbation testing of an industrial centrifugal compressor in an at-speed balancing chamber is discussed in PERTURBATION TESTING FOR ASSESSING ROTOR STABILITY. The instrumentation and data acquisition techniques are described, as well as test results from five different rotor-bearing configurations. The test results were used to choose a bearing design which optimized the rotor stability characteristics. A method determining when full scale perturbation testing is warranted, based on risk management assessment techniques, is described in WHEN IS PERTURBATION TESTING WARRANTED? Methods of quantifying risks are discussed, as well as determining which machines are good candidates for testing

Improved Reliability Through The Use Of Design Audits.

LecturePg. 203-220Rotordynamic design audits of machinery and systems can be used to identify potential problems before manufacture, thus preventing costly project delays and downtime. Machinery engineers need to understand the types of analyses that can be performed to evaluate proposed designs. Understanding the analysis types can also help the engineer to determine if the audit is necessary and/or economically desirable. The types of audits that should be performed are described. Typical analysis results are presented along with guidelines for their interpretation

Piping Vibration Analysis.

Tutorialpg. 119-134Excessive piping vibrations are a major cause of machinery downtime, leaks, fatigue failures, high noise, fires, and explosions in refineries and petrochemical plants. Excessive vibration levels usually occur when a mechanical natural frequency of the piping system is excited by some pulsation or mechanical source. The vibration mode shapes usually involve lateral vibrations and/or shell wall radial vibrations. Simplified methods are presented for analyzing lateral and shell wall piping vibrations and judging their severity. The methods are thought to be conservative and are intended to be used as screening criteria to determine if more sophisticated analyses, such as computer stress modelling or strain gage testing are necessary. Frequency factors for calculating the mechanical natural frequencies for the classical piping configurations (uniform straight beams) and various piping bend configurations are presented. Factors are presented to compensate the natural frequency calculations for concentrated and distributed weight effects. The relationships between piping vibration displacement, velocity and stress are presented and criteria for judging the severity of piping vibration in terms of the endurance stress limit are shown. The mechanisms that can excite piping vibrations will be discussed, as well as methods for controlling their severity

Diagnosis And Solution Of High Noise And Vibration Issues After A Propylene Refrigeration Compressor Rerate.

Case Stud

Reciprocating Compressors 101: The User's Perspective

Short CourseThis course will present the basic concepts of reciprocating compressor applications from a user’s perspective. There is an introductory section on application basics (why recips?), including selection criteria and industry standards (API 618, etc.). Compressor components, the basic compression cycle, capacity control, pistons, rings, rods and lubrication essentials are covered

The Grizzly, February 25, 1983

USGA Plans Communication Revision • Foley, D\u27Alesio First Place Winners at Talent Show • College Union Holds Tenth Anniversary • Ritter Production Opens: Skin of Our Teeth • Mass is Popular: Newman Society Links U.C. • Small Heads Alcohol Committee • SPC Seeks Editors • Union Calendar • Grizzly Looks For New Business Manager • Winterfest 1983: International Desserts Festival Tonight • Winterfest Schedule • Letters to the Editor: Admissions Dean Corrects Errors; Hoop Club President Responds; Student Reacts Negatively • Social Life at Ursinus Should be Improved • In the Gates • Registrar Announces Pre-Registration • President\u27s Corner • Roving Reporter: Do You Think the New Alcohol Policy Proposed by the Administration was the Correct Way to Handle the Situations That Occurred on Campus? • Bears Drown Monarchs • Women\u27s Swimming Ends 10-1 • MAC Competition: Wrestlers Take Seventh • Gymnasts Move up a Rank • Lady Hoopsters Finish With Victoryhttps://digitalcommons.ursinus.edu/grizzlynews/1095/thumbnail.jp

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London