bluuebunny/crossref_metadata_2025 huggingface dataset:
Transferring critically ill patients home to die: developing a clinical guidance document
Authors: Coombs Maureen A , Darlington Anne‐Sophie , Long‐Sutehall Tracy , Richardson Alison
Published: February 2015

Background

With preferred place of care at the time of death a key consideration in end of life care, it is important that transfer home be considered for critically ill patients who want this as part of their end of life care. However, there is limited guidance available to inform the transfer of critically ill patients home to die.

Aims and Objectives

To develop clinical guidance on the practice of transferring patients home to die for doctors and nurses in critical care.

Design

Consensus methodology.

Methods

At a one‐day national event, stakeholders from cross‐community and hospital settings engaged in group work wherein ‘virtual clinical teams’ mapped out, and agreed on, the processes involved in transferring critically ill patients home to die. Using two clinical cases and nominal group technique, factors were identified that promoted and inhibited transfer home and areas in need of development. Findings from the day informed development of a clinical guidance document.

Results

Eighty‐five stakeholders attended the event from across England. The majority of stakeholders strongly agreed that transfer of critically ill patients home to die was a good idea in principle. Stakeholders identified ‘access to care in the community’ (n= 22, 31.4%) and ‘unclear responsibility for care of patient’ (n= 17, 24.3%) as the most important barriers. Consensus was reached on the processes and decision‐making required for transfer home and was used to inform content of a clinical practice guidance document. This underwent further refinement following review by 14 clinicians. A final document in the form of a flow chart was developed.

Conclusions

Transferring critically ill patients home to die is a complex, multifactorial process involving health care agencies across the primary and secondary care interface. The guidance developed from this consensus event will enable staff to actively consider the practice of transferring home to die in appropriate patients.
Unsuccessful Pulsed Radiofrequency of the Sphenopalatine Ganglion in Patients with Chronic Cluster Headache and Subsequent Successful Thermocoagulation
Authors: Bendersky Damián Claudio , Hem Santiago Matias , Yampolsky Claudio Gustavo
Published: February 2015

We present the results of pulsed and continuous radiofrequency (CRF) of the sphenopalatine ganglion in a case series of 3 patients with chronic cluster headache (CCH). Three patients were referred to our neurosurgical department because of CCH, which was refractory to pharmacological treatment. They underwent pulsed radiofrequency of the sphenopalatine ganglion (PRF‐SPG), and the procedure was performed through an infrazygomatic approach. In the PRF procedures, we applied 2 cycles of PRF at 42°C and 45 V for 120 seconds, with a pulse frequency of 2 Hz and a pulse width of 20 ms. In those procedures where thermocoagulation was carried out, 2 CRF lesions at 80°C for 90 seconds each were performed. Following corticosteroid and local anesthetic (40 mg of methylprednisolone and 1 mL of 1% lidocaine) injection, 2 patients had no pain relief at all, whereas the third one experienced a partial response, which lasted only 1 month and his pain then returned to its baseline level. Thus, this outcome was assessed as a nonsustained partial response. Therefore, all of them underwent a CRF lesioning of the SPG, and after this procedure, they achieved complete pain relief until the end of the follow‐up period. Furthermore, the associated autonomic manifestations disappeared. The 3 patients presented in this case series failed to achieve adequate pain relief after PRF‐SPG. However, these same patients subsequently underwent a successful CRF of the SPG.
Necessity of human milk banking in Japan: Questionnaire survey of neonatologists
Authors: Mizuno Katsumi , Sakurai Motoichiro , Itabashi Kazuo
Published: February 2015

Background

If their own mother's milk (OMM) is not available, another mother's milk may be used for extremely low‐birthweight (ELBW) infants. Human milk is a bodily fluid, however, therefore we have assumed that other mother's milk is currently seldom given to infants despite its superiority to formula. Although the World Health Organization and the American Academy of Pediatrics have recommended using donor human milk (DHM) from a human milk bank (HMB) in the case that OMM is not available, there is no HMB in Japan. To assess whether other mother's milk is used for ELBW infants and whether an HMB is necessary in Japan, we surveyed neonatal intensive care units (NICU) via questionnaire.

Methods

The questionnaire was sent by email to members of the Japanese Neonatologist Association who are responsible for NICU.

Results

In total, 126 completed questionnaires (70.7%) were returned and analyzed. One‐fourth of NICU give other mother's milk to ELBW infants. The first choice of nutrition is OMM, but other mother's milk or formula is given to infants at 19% of NICU if OMM is unavailable. Approximately three‐fourths of NICU would like an HMB.

Conclusion

Although human milk contains contagious agents and authorities do not recommend giving other mother's milk as a substitute for OMM, other mother's milk is still a choice in NICU in Japan. Many neonatologists, however, would prefer a safer alternative, that is, DHM obtained from an accredited HMB. A well‐regulated HMB should be established and safe DHM should be available for all preterm infants if necessary.
Effect of Oil Overlay on Inhibition Potential of Roscovitine in Sheep Cumulus‐Oocyte Complexes
Authors: Crocomo LF , Marques Filho WC , Ulian CMV , Branchini NS , Silva DT , Ackermann CL , Landim‐Alvarenga FC , Bicudo SD
Published: February 2015

Contents

Inhibitors of cyclin‐dependent kinases, as roscovitine, have been used to prevent the spontaneous resumption of meiosis in vitro and to improve the oocyte developmental competence. In this study, the interference of oil overlay on the reversible arrest capacity of roscovitine in sheep oocytes as well as its effects on cumulus expansion was evaluated. For this, cumulus‐oocyte complexes (COCs) were cultured for 20 h in TCM 199 with 10% foetal bovine serum (Control) containing 75 μm roscovitine (Rosco). Subsequently, they were in vitro matured (IVM) for further 18 h in inhibitor‐free medium with LH and FSH. The culture was performed in Petri dishes under mineral oil (+) or in 96 well plates without oil overlay (−) at 38.5°C and 5% CO2. At 20 and 38 h, the cumulus expansion and nuclear maturation were evaluated under stereomicroscope and by Hoechst 33342 staining, respectively. No group presented cumulus expansion at 20 h. After additional culture with gonadotrophins, a significant rate of COCs from both Control groups (+/−) exhibited total expansion while in both Rosco groups (+/−) the partial expansion prevailed. Among the oocytes treated with roscovitine, 65.2% were kept at GV in the absence of oil overlay while 40.6% of them reached MII under oil cover (p < 0.05). This meiotic arrest was reversible, and proper meiosis progression also occurred in the Control groups (+/−). So, the culture system without oil overlay improved the meiotic inhibition promoted by roscovitine without affecting the cumulus expansion rate or the subsequent meiosis progression.
Risk factors for lower extremity injuries among half marathon and marathon runners of the Lage Landen Marathon Eindhoven 2012: A prospective cohort study in the Netherlands
Authors: van Poppel D. , de Koning J. , Verhagen A. P. , Scholten‐Peeters G. G. M.
Published: February 2015

To determine risk factors for running injuries during the Lage Landen Marathon Eindhoven 2012. Prospective cohort study. Population‐based study. This study included 943 runners. Running injuries after the Lage Landen Marathon. Sociodemographic and training‐related factors as well as lifestyle factors were considered as potential risk factors and assessed in a questionnaire 1 month before the running event. The association between potential risk factors and injuries was determined, per running distance separately, using univariate and multivariate logistic regression analysis. In total, 154 respondents sustained a running injury. Among the marathon runners, in the univariate model, body mass index ≥ 26 kg/m2, ≤ 5 years of running experience, and often performing interval training, were significantly associated with running injuries, whereas in the multivariate model only ≤ 5 years of running experience and not performing interval training on a regular basis were significantly associated with running injuries. Among marathon runners, no multivariate model could be created because of the low number of injuries and participants. This study indicates that interval training on a regular basis may be recommended to marathon runners to reduce the risk of injury.
Influence of 4 weeks of bovine colostrum supplementation on neutrophil and mucosal immune responses to prolonged cycling
Authors: Jones A. W. , Thatcher R. , March D. S. , Davison G.
Published: February 2015

Bovine colostrum (COL) has been advocated as a nutritional countermeasure to exercise‐induced immune dysfunction. The aims of this study were to identify the effects of 4 weeks of COL supplementation on neutrophil responses and mucosal immunity following prolonged exercise. In a randomized double‐blind, parallel group design, participants [age 28 ± 8 years; body mass 79 ± 7 kg; height 182 ± 6 cm; maximal oxygen uptake () 55 ± 9 mL/kg/min] were assigned to 20 g per day of COL (n = 10) or an isoenergetic/isomacronutrient placebo (PLA; n = 10) for 4 weeks. Venous blood and unstimulated saliva samples were obtained before and after 2.5 h of cycling at 15% Δ (∼55–60% ). A significantly greater formyl‐methionyl‐leucyl phenylalanine‐stimulated oxidative burst was observed in the COL group compared with PLA group (P < 0.05) and a trend toward a time × group interaction (P = 0.06). However, there was no effect of COL on leukocyte trafficking, phorbol‐12‐myristate‐13‐acetate‐stimulated oxidative burst, bacterial‐stimulated neutrophil degranulation, salivary secretory IgA, lactoferrin or lysozyme (P > 0.05). These findings provide further evidence of the beneficial effects of COL on receptor‐mediated stimulation of neutrophil oxidative burst in a model of exercise‐induced immune dysfunction.
Anterior cruciate ligament injury about 20 years post‐treatment: A kinematic analysis of one‐leg hop
Authors: Tengman E. , Grip H. , Stensdotter AK. , Häger C. K.
Published: February 2015

Reduced dynamic knee stability, often evaluated with one‐leg hops (OLHs), is reported after anterior cruciate ligament (ACL) injury. This may lead to long‐standing altered movement patterns, which are less investigated. 3D kinematics during OLH were explored in 70 persons 23 ± 2 years after ACL injury; 33 were treated with physiotherapy in combination with ACL reconstruction (ACLR) and 37 with physiotherapy alone (ACLPT). Comparisons were made to 33 matched controls. We analyzed (a) maximal knee joint angles and range of motion (flexion, abduction, rotation); (b) medio‐lateral position of the center of mass (COM) in relation to knee and ankle joint centers, during take‐off and landing phases. Unlike controls, ACL‐injured displayed leg asymmetries: less knee flexion and less internal rotation at take‐off and landing and more lateral COM related to knee and ankle joint of the injured leg at landing. Compared to controls, ACLR had larger external rotation of the injured leg at landing. ACLPT showed less knee flexion and larger external rotation at take‐off and landing, and larger knee abduction at Landing. COM was more medial in relation to the knee at take‐off and less laterally placed relative to the ankle at landing. ACL injury results in long‐term kinematic alterations during OLH, which are less evident for ACLR.
Demographic differences in sport performers’ experiences of organizational stressors
Authors: Arnold R. , Fletcher D. , Daniels K.
Published: February 2015

Organizational stressors are particularly prevalent across sport performers’ experiences and can influence their performance, health, and well‐being. Research has been conducted to identify which organizational stressors are encountered by sport performers, but little is known about how these experiences vary from athlete to athlete. The purpose of this study was to examine if the frequency, intensity, and duration of the organizational stressors that sport performers encounter vary as a function of gender, sport type, and performance level. Participants (n = 1277) completed the Organizational Stressor Indicator for Sport Performers (OSI‐SP; Arnold et al., 2013), and the resultant data were analyzed using multivariate analyses of covariance. The findings show that demographic differences are apparent in the dimensions of the goals and development, logistics and operations, team and culture, coaching, and selection organizational stressors that sport performers encounter. More specifically, significant differences were found between males and females, between team and individual‐based performers, and between performers competing at national or international, regional or university, and county or club levels. These findings have important implications for theory and research on organizational stress, and for the development of stress management interventions with sport performers.
Intrathecal gadodiamide for identifying subarachnoid and ventricular neurocysticercosis
Authors: Higuera‐Calleja Jesús , Góngora‐Rivera Fernando , Soto‐Hernández José Luis , Del‐Brutto Oscar H. , Moreno‐Andrade Talía , Gutiérrez‐Alvarado Ramón , Rodríguez‐Carbajal Jesús
Published: February 2015

Objective

Some neurocysticercosis cysts may remain hidden despite novel MRI sequences. This study evaluates the diagnostic value of gadodiamide (GDD)‐contrasted MRI cisternography in selected cases of neurocysticercosis.

Methods

We included patients aged 18–65 years with a probable diagnosis of subarachnoid cysticercosis in whom previous neuroimaging studies failed to demonstrate the presence of cysts. One millilitre of GDD was administered intrathecally as a contrast agent with subsequent performance of MRI.

Results

Fourteen patients were included. Optimal contrast diffusion was achieved in nine patients, and partial diffusion was achieved in 4. Intracranial vesicles were identified in 10 patients, with the presence of more than 60 basal subarachnoid vesicles being revealed in all, with five cysts in the fourth ventricle in four patients and a floating cyst in the lateral ventricle in one. In one case, intrathecal GDD demonstrated spinal cysticercosis. No adverse events were reported after intrathecal GDD administration.

Conclusions

Intrathecal GDD administration is useful for the diagnosis of subarachnoid and intraventricular neurocysticercosis and can be used to improve diagnostic accuracy in selected cases.
Women's perceptions of the quality of emergency obstetric care in a referral hospital in rural Tanzania
Authors: Stal Karen Berit , Pallangyo Pedro , van Elteren Marianne , van den Akker Thomas , van Roosmalen Jos , Nyamtema Angelo
Published: February 2015

Objectives

To assess perceptions of the quality of obstetric care of women who delivered in a rural Tanzanian referral hospital.

Methods

A descriptive‐exploratory qualitative study, using semistructured in‐depth interviews and participatory observation. Nineteen recently delivered women and 3 health workers were interviewed.

Results

Although most women held positive views about the care they received in hospital, several participants expressed major concerns about negative attitudes of healthcare workers. Lack of medical communication given by care providers constituted a major complaint.

Conclusions

A more positive attitude by health workers and the provision of adequate medical information may promote a more positive hospital experience of women in need of obstetric care and enhance attendance.
Cost of neurocysticercosis patients treated in two referral hospitals in Mexico City, Mexico
Authors: Bhattarai Rachana , Carabin Hélène , Proaño Jefferson V. , Flores‐Rivera Jose , Corona Teresa , Flisser Ana , Budke Christine M.
Published: February 2015

Objectives

To estimate annual costs related to the diagnosis, treatment and productivity losses among patients with neurocysticercosis (NCC) receiving treatment at two referral hospitals, the Instituto Nacional de Neurologia y Neurocirugia (INNN) and the Hospital de Especialidades of the Instituto Mexicano del Seguro Social (HE‐IMSS), in Mexico City from July 2007 to August 2008.

Methods

Information on presenting clinical manifestations, diagnostic tests, hospitalisations, surgical procedures and other treatments received by NCC outpatients was collected from medical charts, and supplemented by an individual questionnaire regarding productivity losses and out‐of‐pocket expenses related to NCC.

Results

The annual average per‐patient direct costs were US$ 503 (95% CI: 414–592) and US$ 438 (95% CI: 322–571) for patients without a history of hospitalisation and/or surgery seen at the INNN and the HE‐IMSS, respectively. These costs increased to US$ 2506 (95% CI: 1797–3215) and US$ 2170 (95% CI: 1303–3037), respectively, for patients with a history of hospitalisation and/or surgery. The average annual per‐patient indirect costs were US$ 246 (95% CI: 165–324) and US$ 114 (95% CI: 51–178), respectively, using minimum salary wages for individuals not officially employed.

Conclusions

The total annual cost for patients who had and had not been hospitalised and/or undergone a surgical procedure for the diagnosis or treatment of NCC corresponded to 212% and 41% of an annual minimum wage salary, respectively. The disease tends to affect rural socioeconomically disadvantaged populations and creates health disparities and significant economic losses in Mexico.
Beyond Single‐Level Accounts: The Role of Cognitive Architectures in Cognitive Scientific Explanation
Authors: Cooper Richard P. , Peebles David
Published: February 2015

We consider approaches to explanation within the cognitive sciences that begin with Marr's computational level (e.g., purely Bayesian accounts of cognitive phenomena) or Marr's implementational level (e.g., reductionist accounts of cognitive phenomena based only on neural‐level evidence) and argue that each is subject to fundamental limitations which impair their ability to provide adequate explanations of cognitive phenomena. For this reason, it is argued, explanation cannot proceed at either level without tight coupling to the algorithmic and representation level. Even at this level, however, we argue that additional constraints relating to the decomposition of the cognitive system into a set of interacting subfunctions (i.e., a cognitive architecture) are required. Integrated cognitive architectures that permit abstract specification of the functions of components and that make contact with the neural level provide a powerful bridge for linking the algorithmic and representational level to both the computational level and the implementational level.
Hypertension: a systemic key to understanding local keloid severity
Authors: Arima Juri , Huang Chenyu , Rosner Bernard , Akaishi Satoshi , Ogawa Rei
Published: February 2015

This study assessed whether hypertension, a circulating factor, influences local keloid severity. This retrospective cross‐sectional study involved 304 consecutive patients (13–78 years old) with keloids who were surgically treated in our hospital between January 2011 and August 2013. Their blood pressure (BP), age and gender, and the size and number of their keloids before surgery were recorded. Ordinal logistic regression analyses showed that BP associated significantly with both keloid size and number (all p < 0.0001). Age also associated with keloid size (p < 0.0001). However, a Goodness‐of‐fit chi‐square test showed that the prevalence of hypertension was not higher among keloid patients than in the general Japanese population. This study provides epidemiological evidence for the possibility that primary hypertension may aggravate keloids. We propose that the skin, along with the heart and liver, is a target organ of hypertension. The observations of this study, which require validation with large‐scale prospective interventional trials, suggest that keloid patients should be screened for hypertension and that antihypertensive treatments may be of prophylactic and therapeutic value for skin fibrosis.
Axial Inlet Conversion to a Centrifugal Compressor With Magnetic Bearings
Authors: Novecosky Tom
Published: March 2015

NOVA’s Alberta Gas Transmission Division transports natural gas via pipeline throughout the province of Alberta, Canada, exporting it to eastern Canada, United States and British Columbia. It is a continuing effort to operate the facilities and pipeline at the highest possible efficiency. One area being addressed to improve efficiency is compression of the gas. By improving compressor efficiency, fuel consumption and hence operating costs can be reduced.

One method of improving compressor efficiency is by converting the compressor to an axial inlet configuration, a conversion that has been carried out more frequently in the past years. Concurrently, conventional hydrodynamic bearings have been replaced with magnetic bearings on many centrifugal compressors. This paper discusses the design and installation for converting a radial overhung unit to an axial inlet configuration, having both magnetic bearings and a thrust reducer. The thrust reducer is required to reduce axial compressor shaft loads, to a level which allows the practical installation of magnetic bearings within the space limitations of the compressor (Bear and Gibson, 1992).
One-Dimensional Methods for Accurate Prediction of Off-Design Performance Behavior of Axial Turbines
Authors: Schobeiri T.
Published: March 2015

The turbine component of a gas turbine engine is frequently subjected to extreme operation conditions associated with significant changes in mass flow, turbine inlet temperature, pressure and rotational speed. These off-design operation conditions significantly affect the flow deflection within the turbine stage, which consists of individual stator and rotor rows. As a result, the stage parameters representing the velocity diagram will change and effect the efficiency and performance of the stage and, thus, the turbine. A differential and integral method is presented for predicting the performance behavior of turbines under extreme off-design conditions. Both methods are applied to a multistage turbine for which the off-design performance is calculated and compared with the measurement.
The Vortex Behaviour of the Rotating-Stall Cell of a Centrifugal Compressor With Vaned Diffuser
Authors: Chen Y. N. , Seidel U. , Haupt U. , Rautenberg M.
Published: March 2015

The aerodynamic behaviour of the rotating-stall cell of a centrifugal compressor with radial blading and vaned diffuser is investigated experimentally using two stagnation pressure transducers located parallel to each other on the opposing walls of the semi-vaneless annular space between the impeller and the diffuser. The transducers are turned simultaneously step by step through an angle of 360° during the measurement, so that the flow field of both the forward and reverse flows and the swirl flow components can be detected in the stalled and the unstalled regions.

It was shown in the previous papers of the authors (1991 b) that the jet and wake in the flow of the blade channel in the normal operating range are cores of longitudinal vortices with opposite rotational sense. During rotating stall, the jet of a blade channel bends over the outlet edge of the blade and is converted into the wake of the neighbouring one to form a vortex loop around the blade in question. The swirling speed of this vortex loop (the vorticity) is measured to be about twice impeller speed for the present case. The vortex loops of the adjacent blades then join together to form a bubble, the stall cell, embodying the region of the stalled blades.

The outer reach of the vortex bubble forms the border of the outer lobe of the Rossby waves associated with the vortex pair “high” (H) and “low” (L) guiding the stall cell. The longitudinal-vortex-nature of the jet stream along the flank of the Rossby wave, as determined recently in a vaneless diffuser by the authors (1991a), is confirmed in the present investigation. Its intensity reaches a velocity of about 20% u2 when measured in the absolute frame, or 120% u2 when measured in the rotating impeller frame, superimposed by a swirling component of (1 to 4) x ωimp (u2 = tangential velocity of the impeller outlet. ωimp = angular velocity of the impeller).
Calculation of Turbulent Flow for an Enclosed Rotating Cone
Authors: May N. E. , Chew J. W. , James P. W.
Published: March 2015

Prediction of the flow in the cavity between a rotating cone and an outer stationary cone with and without throughflow is considered. A momentum-integral method and a finite difference method for solution of the Reynolds-averaged Navier-Stokes equations with a mixing-length model of turbulence are applied. These two methods have previously been validated for flow between co-rotating and rotor-stator disc systems, but have not been properly tested for conical systems. Both methods have been evaluated by comparing predictions with the experimental measurements of other workers. There is good agreement for cone half angles greater than or equal to 60’ but discrepancies are evident for smaller angles. ‘Taylor-type’ vortices, the existence of which has been postulated by other workers and which are not captured by the present steady, axisymmetric models, may contribute to these discrepancies.
Aeroloads and Secondary Flows in a Transonic Mixed Flow Turbine Stage
Authors: Kirtley K. R. , Beach T. A. , Rogo Cass
Published: March 2015

A numerical simulation of a transonic mixed flow turbine stage has been carried out using an average passage Navier-Stokes analysis. The mixed flow turbine stage considered here consists of a transonic nozzle vane and a highly loaded rotor. The simulation was run at the design pressure ratio and is assessed by comparing results with those of an established throughflow design system. The three-dimensional aerodynamic loads are studied as well as the development and migration of secondary flows and their contribution to the total pressure loss. The numerical results indicate that strong passage vortices develop in the nozzle vane, mix out quickly, and have little impact on the rotor flow. The rotor is highly loaded near the leading edge. Within the rotor passage, strong spanwise flows and other secondary flows exist along with the tip leakage vortex. The rotor exit loss distribution is similar in character to that found in radial inflow turbines. The secondary flows and non-uniform work extraction also tend to significantly redistribute a non-uniform inlet total temperature profile by the exit of the stage.
Liquid Sheet Disintegration and Atomization Process on a Simplified Airblast Atomizer
Authors: LaVergne G. , Trichet P. , Hebrard P. , Biscos Y.
Published: March 2015

Liquid sheet break-up in co flowing shear flow is the mean by which liquids are atomized in practical injectors for gas turbine combustors. The present study explores experimentally the mechanisms of liquid sheet instabilities and spray formation. Experiments are conducted on four airblast geometries.

A high speed video camera associated to an image processing unit was used to study the liquid sheet instabilities. A microphone and a frequency analyzer were used to track the disintegration frequency. Instability amplitude and disintegration lenght of the liquid sheet were measured.

A two component Phase Doppler Particle Analyzer was used to characterize the resultant spray. The spatial distribution of the particle size is influenced by the swirling flow field.

These experimental results will be used to assess models of fuel sheet instabilities and disintegration.
Modification of Combustor Stoichiometry Distribution for Reduced NOx Emission From Aircraft Engines
Authors: Sturgess G. J. , McKinney R. , Morford S.
Published: March 2015

Measurements of the emissions from an experimental engine were analyzed to construct a design chart for the reduction of oxides of nitrogen (NOx) in conventional combustors. The design chart was used to reconfigure the stoichiometry distribution of the combustor of a production engine so as to reduce NOx while holding the emissions of carbon monoxide, unburned hydrocarbons and smoke well below existing regulations. Combustion section pressure loss and combustor outlet temperature distributions were substantially unchanged. The modified design was refined with the aid of computational fluid dynamics calculations to optimize the emissions reduction. Worthwhile reductions in NOx were obtained with combustor modifications that are transparent to the engine user.
Effect of Trailing-Edge Ejection on Local Heat (Mass) Transfer in Pin Fin Cooling Channels in Turbine Blades
Authors: Mcmillin R. D. , Lau S. C.
Published: March 2015

Experiments are conducted to study the local heat transfer distribution and pressure drop in a pin fin channel that models the cooling passages in modern gas turbine blades. The detailed heat/mass transfer distribution is determined via the naphthalene sublimation technique for flow through a channel with a 16-row, staggered 3 × 2 array of short pin fins (with a height-to-diameter ratio of 1.0, and streamwise and spanwise spacing-to-diameter ratios of 2.5) and with flow ejection through holes in one of the side walls and at the straight flow exit (to simulate ejection through holes along the trailing edges and through tip bleed holes of turbine blades). The pin fin heat/mass transfer and the channel wall heat/mass transfer are obtained for the straight-flow-only and the ejection-flow cases. The results show that the regional pin heat/mass transfer coefficients are generally higher than the corresponding regional wall heat/mass transfer coefficients in both cases. When there is side wall flow ejection, a portion of the flow turns to exit the ejection holes and the rate of heat/mass transfer decreases in the straight flow direction as a result of the reducing mass flow rate along the channel. The rate of cooling air flow through a pin fin channel in a gas turbine blade must be increased to compensate for the “loss” of the cooling air through trailing edge ejection holes, so that the blade tip is cooled sufficiently.
Incidence Angle and Pitch-Chord Effects on Secondary Flows Downstream of a Turbine Cascade
Authors: Perdichizzi A. , Dossena V.
Published: March 2015

This paper describes the results of an experimental investigation of the three-dimensional flow downstream of a linear turbine cascade at off-design conditions. The tests have been carried out for five incidence angles from −60 to +35 degrees, and for three pitch-chord ratios: s/c = 0.58,0.73,0.87. Data include blade pressure distributions, oil flow visualizations, and pressure probe measurements. The secondary flow field has been obtained by traversing a miniature five hole probe in a plane located at 50% of an axial chord downstream of the trailing edge. The distributions of local energy loss coefficients, together with vorticity and secondary velocity plots show in detail how much the secondary flow field is modified both by incidence and cascade solidity variations. The level of secondary vorticity and the intensity of the crossflow at the endwall have been found to be strictly related to the blade loading occurring in the blade entrance region. Heavy changes occur in the spanwise distributions of the pitch averaged loss and of the deviation angle, when incidence or pitch-chord ratio is varied.
Low Aspect Ratio Transonic Rotors: Part 2 — Influence of Location of Maximum Thickness on Transonic Compressor Performance
Authors: Wadia A. R. , Law C. H.
Published: March 2015

Transonic compressor rotor performance is sensitive to variations in several known design parameters. One such parameter is the chordwise location of maximum thickness. This article reports on the design and experimental evaluation of two versions of a low aspect ratio transonic rotor that had the location of the tip blade section maximum thickness moved forward in two increments from the nominal 70 percent to 55 and 40 percent chord length, respectively. The original hub characteristics were preserved and the maximum thickness location was adjusted proportionately along the span. Although designed to satisfy identical design speed requirements, the experimental results reveal significant variation in the performance of the rotors. At design speed, the rotor with its maximum thickness located at 55 percent chord length attains the highest peak efficiency amongst the three rotors but has lowest flow rollback relative to the other two versions. To focus on current ruggedization issues for transonic blading (e.g. bird, ice ingestion), detailed comparison of test data and analysis to characterize the aerodynamic flow details responsible for the measured performance differences was confined to the two rotors with the most forward location of maximum thickness. A three-dimensional viscous flow analysis was used to identify the performance enhancing features of the higher efficiency rotor and to provide guidance in the interpretation of the experimental measurements. The computational results of the viscous analysis shows that the difference in performance between the two rotors can be attributed to the higher shock losses that result from the increased leading edge “wedge angle” as the maximum thickness is moved closer to the leading edge. The test data and the three-dimensional viscous analysis also reveal that the higher efficiency rotor achieves the same static pressure rise potential and loading at a higher flow level than its lesser efficient counterpart and this is responsible for its resulting lower flow rollback and apparent loss in stall margin. Comparison of the peak efficiencies attained by the two rotors described in this article with the baseline ruggedized rotor performance presented in part 1 of this paper suggests the existence of an optimum maximum thickness location at 55 to 60 percent chord length for such low aspect ratio transonic rotors.
Time-Averaged Heat Transfer and Pressure Measurements and Comparison With Prediction for a Two-Stage Turbine
Authors: Dunn M. G. , Kim J. , Civinskas K. C. , Boyle R. J.
Published: March 2015

Time-averaged Stanton number and surface-pressure distributions are reported for the first-stage vane row and the first-stage blade row of the Rocketdyne Space Shuttle Main Engine two-stage fuel-side turbine. These measurements were made at 10%, 50%, and 90% span on both the pressure and suction surfaces of the component. Stanton-number distributions are also reported for the second-stage vane at 50% span. A shock tube is used as a short-duration source of heated and pressurized air to which the turbine is subjected. Platinum thin-film pages are used to obtain the heat-flux measurements and miniature silicone-diaphragm pressure transducers are used to obtain the surface pressure measurements. The first-stage vane Stanton number distributions are compared with predictions obtained using a quasi-3D Navier-Stokes solution and a version of STAN5. This same N-S technique was also used to obtain predictions for the first blade and the second vane.
Tip Clearance Effect on Heat Transfer and Leakage Flows on the Shroud-Wall Surface in an Axial Flow Turbine
Authors: Kumada Masaya , Iwata Satoshi , Obata Masakazu , Watanabe Osamu
Published: March 2015

An axial flow turbine for a turbocharger is used as a test turbine, and the local heat transfer coefficient on the surface of the shroud is measured under uniform heat flux conditions. The nature of the tip clearance flow on the shroud surface and a flow pattern in the downstream region of the rotor blades are studied, and measurements are obtained by using a hot-wire anemometer in combination with a periodic multi-sampling and an ensemble averaging technique. Data are obtained under on- and off-design conditions. The effects of inlet flow angle, rotational speed and tip clearance on the local heat transfer coefficient are elucidated. The mean heat transfer coefficient is correlated with the tip clearance, and the mean velocity is calculated by the velocity triangle method for approximation. A leakage flow region exists in the downstream direction beyond the middle of the wall surface opposite the rotor blade, and a leakage vortex is recognized at the suction side near the trailing edge.
Measurement of the Three-Dimensional Tip Region Flowfield in an Axial Compressor
Authors: Stauter R. C.
Published: March 2015

A two-color, five-beam LDV system has been configured to make simultaneous three-component velocity measurements of the flow field in a two-stage axial compressor model. The system has been used to make time-resolved measurements both between compressor blade rows as well as within the rotating blade passages in an axial compressor. The data show the nature and behavior of the complex, three-dimensional flow phenomena present in the tip region of a compressor as they convect downstream. In particular, the nature of the tip leakage vortex is apparent, being manifested by high blockage as well as the expected vortical motion. The data indicate that the radial flows associated with the tip leakage vortex begin to decrease while within the rotor passage, and that they temporarily increase aft of the passage.
Heat Transfer to a Rotating Drum in an Annulus With a Stator Blade Row and Axial Throughflow
Authors: Childs P. R. N. , Turner A. B. , Vaughan C. M. , Rayner D. , Bayley F. J.
Published: March 2015

This paper describes an experimental and numerical investigation of heat transfer to a rotor drum rotating in an annulus with an axial throughflow of air. The application of the work is principally to the transient heating of axial compressor rotor drums, and the results obtained extend the range of previously published correlations by an order of magnitude. Rotational Reynolds numbers (Reω = ωri2/ν) up to 1.5 × 106 and axial Reynolds numbers (ReD = uaDh/ν, Dh = 2(ro – ri)) up to 3.7 × 105 have been achieved experimentally.

A new experimental facility is described in which a 400mm diameter rotor drum, instrumented with miniature thermopile type heat flux meters and thermocouples, can be air turbine driven at up to 10000rpm. The drum rotates in an annulus with a gap of 30mm in which complete rows of stator vanes can be mounted to enable the effect of vane/rotor drum clearance to be examined. A correlation for the heat transfer between the rotor drum and a stator blade row is presented for varying axial and rotational Reynolds numbers and blade/rotor drum radial clearance.
The Influence of Coal Slurry Fuel Properties on the Performance of a Bench Scale Two-Stage Slagging Combustor
Authors: Cowell L. H. , Wen C. S. , LeCren R. T.
Published: March 2015

Fuel specifications for a coal-fueled industrial gas turbine are being determined through bench scale testing of a two-stage slagging combustor with coal water mixtures (CWM) possessing different properties. Twelve CWMs have been formulated with variations in coal loading, ash concentration, fuel additives, coal particle size, and coal type. The test combustor is operated at 7 bars with a 600 K air inlet temperature in a high pressure test facility. The two-stage slagging combustor (TSSC) features a rich burning, slagging primary zone and a lean secondary zone. Combustor performance is characterized by measurements of pollutant emissions, slag capture, particulate emissions, and coal utilization. The combustor has demonstrated a high degree of fuel property flexibility with performance remaining above goals in most tests. The properties of the CWMs and the test results are discussed.
Numerical Generator Protection Offers New Benefits of Gas Turbines
Authors: Ilar M. , Wittwer M.
Published: March 2015

This article describes the benefits offered by a new type of numerical protection system, applied to gas turbine generators.

World-wide more than 100 different generators with a total rating of about 6000 MW are equipped with this type of protection system.

This protection system is completely independent of other power plant equipment, with its own DC power supplies, input isolating auxiliary current and voltage transformers and optocoupler or relay type binary input/output devices as well as serial communication links. The heart of the system is a multiprocessor high speed bus capable of handling the communication between the measuring inputs, the protection algorithm processor (s) and the output units.

The system makes use of a large library of modular, pretested protective functions.

Continuous self-monitoring enhances the availability of the complete protective system.

Modern, well coordinated protection and turbine control systems offer new advantages to the user such as faster handling of emergency situations through the availability of more and better information together with the possibility of faster and more detailed fault analysis. In addition, a reduction in the time required for commissioning, e.g. for cables and instrument transformers, can be realized.

This paper is presented to provide some understanding of the application of the protection system introduced here, in particular in connection with the ABB gas turbine generator unit type GT11N. Also introduced are the main components involved, such as numerical protective functions, self-monitoring of protection systems, and data exchange.
1/4 Scale Hot Flow Model Test of a GE LM2500 Exhaust System
Authors: Vandam D. , Birk A. M.
Published: March 2015

A facility has been constructed to test exhaust systems for the GE LM2500 Gas Turbine. The facility is capable of simulating the hot flow exhaust conditions for the LM2500 in 1/4 scale.

The facility was constructed to study LM2500 exhaust system performance including the effects of small changes in the geometry of the LM2500 exhaust collector and also to study the effects of devices such as infrared signature suppressors on the overall exhaust system performance. The facility is currently instrumented to measure local static and total pressures, local swirl angles, exit plane total and static pressure distribution, and primary (engine exhaust) and secondary (enclosure cooling air) mass flow rates. The facility has been constructed to accommodate a variety of exhaust uptake geometries. Tests were recently conducted to study certain aspects of exhaust system performance. Sample data is presented and comparisons are made with other available data.
Design of Multi-Stage Turbomachinery Blading by the Circulation Method: Actuator Duct Limit
Authors: Dang T. Q. , Wang T.
Published: March 2015

This paper presents an extension of a recently developed three-dimensional inverse method for turbomachine blades to handle multi-stage machines in the limit of an infinite number of blades in each blade row. The axisymmetric flowfield is assumed to be inviscid, compressible, and rotational. The use of blockage and entropy-increase terms are included in the theory to model losses. An iterative procedure is presented for the calculations of the blade profiles which produce prescribed swirl schedules in the bladed regions. The numerical technique employed to solve the relevant equations is based on a finite-volume formulation. The method is applied to the design of a low-pressure multi-stage centrifugal compressor used in industrial processing.
Analysis of General Electric Model 7001 First Stage Nozzle Cracking
Authors: Bernstein Henry L. , McClung R. Craig , Sharron T. R. , Allen James M.
Published: March 2015

Analyses of first stage nozzle cracking in General Electric Model 7001B and 7001E industrial gas turbines are presented. Empirical algorithms are developed to predict the maximum extent of cracking that is visible on these nozzles as a function of engine cyclic history and the number of fired hours. It is shown that the algorithms predict this cracking to within a factor of two. Metallurgical analyses of nozzles show that crack growth follows the carbide-matrix interface, environmental attack occurs at the crack tip, and that the microstructure changes by increasing the amount of carbide precipitation which increases the hardness. These metallurgical results, along with mechanical test data and stress analyses from the literature, are used to understand the nature of nozzle cracking. The maximum extent of cracking coincides with locations of maximum thermal stresses as determined by finite element analyses of similar nozzle designs. This location is at the airfoil-shroud junction on the middle vanes of multi-vane castings. The use of these algorithms as a predictive maintenance tool and the ability to visually inspect nozzles in the engine also are discussed.
Evolution and Introduction of the Mars T-14,000 Gas Turbine
Authors: Waldhelm C. M.
Published: March 2015

Solar’s Mars Model T-14,000 gas turbine was developed and introduced as a 10.5-MW (14,100-hp), 33.5% thermal efficiency, industrial second-generation, simple-cycle gas turbine for mechanical-drive, power generation, and gas compression applications. Options include multi-fuel and rating capability with low emissions. Component development, rig and instrumented engine testing, and extended field evaluations evolved prior to market release in 1991.
High Nitrogen Martensitic Steels a New Family of Martensitic Corrosion Resistant Steels for Improved Aerospace Bearing Performance
Authors: Trojahn Werner
Published: March 2015

The need for greater reliablity of corrosion resistant bearings, especially in aerospace and aircraft applications, has led to the development of 15 % Cr-steels with 1 % Mo. A partial exchange of carbon by nitrogen improves corrosion resistance, mechanical properties and bearing life as compared to conventional stainless bearing steels.
Fiber-Reinforced Composites for Gas Turbine Applications
Authors: Stinton D. P. , Lowden R. A. , Besmann T. M.
Published: March 2015

Fiber-reinforced SiC matrix composites are being considered for application in hot-gas turbines. A forced-flow thermal-gradient chemical vapor infiltration process has been developed to fabricate composites of thick-walled tubular geometry common to many components. Fibrous preforms of different fiber architectures (3-dimensionally braided and filament wound) have been investigated to accommodate components with different mechanical property requirements. This paper will discuss the fabrication of tubular fiber-reinforced SiC matrix composites and their mechanical properties.
Analysis of Jet/Wake Mixing in a Vaneless Diffuser
Authors: Mounts Jon S. , Brasz Joost J.
Published: March 2015

A time-dependent, three-dimensional Navier-Stokes algorithm has been developed to study the unsteady flowfield interaction in the impeller and vaneless diffuser of a centrifugal compressor. This study describes the flow phenomena taking place in the entry region of a vaneless diffuser receiving the distorted impeller discharge flow. In the diffuser entry region, the initial dynamic variations in the velocity and flow angle (caused by the so-called jet/wake flow profile of the fluid leaving the impeller passages) mix out quickly. It was also found that the steady-state distortion in the hub-to-shroud plane, with higher through-flow velocities at the hub than at the shroud, persisted over a large area of the diffuser. Fairly large fluctuations in static pressure also persist well into the region where the velocity and flow angles have damped out. The reason for the relatively fast mixing of the dynamic velocity fluctuations is that these fluctuations are transmitted by convection with the local velocity of the fluid particles. Conservation of mass and momentum cause two flows (jet and wake) with different radial and tangential velocities and angles entering a radial vaneless diffuser to mix out rapidly. However, dynamic fluctuations in static pressure propagate with the speed of sound and can persist at larger diffuser radius ratios without violating the continuity and momentum equations.