bluuebunny/crossref_metadata_2025 huggingface dataset:
The Sociocultural Aspects, Professional Characteristics, and Motivational Factors of the First Fellows of the European Committee of Sexual Medicine
Authors: Arbanas Goran , Reisman Yacov , Andrews Shalini
Published: April 2015

Introduction

After a century of development in the field of sexology and decades of attempts to establish the field of sexual medicine, the first examination that led to the qualification as Fellows of the European Committee of Sexual Medicine (FECSM) was held in December 2012.

Aim

This study aims to describe the first European specialists in sexual medicine, their clinical practice, motivation, and professional self-identification.

Methods

A web-based survey of the first FECSM on demographic data, data on the practices of their work (gender of clients, setting, and time frame), and reasons for entering the sexual medicine (five-point Likert rating of motives and open question on other reasons) was conducted.

Main Outcome Measure

Gender, religion, specialty, region, and their association with professional practices of the first FECSM.

Results

The first FECSM have a wide range of experience in the field of sexual medicine (0–30 years) and were mainly men (79%) and urologists (56%). Only 15.5% had other qualifications related to sexual medicine and 60% self-identified as sexual medicine specialists. Only a small proportion of the professional time was dedicated to the practice of sexual medicine. The primary speciality influenced the gender of their patients seen, setting of work (couple vs. individuals), and time spent with patients. Only a minority managed sexual problems in women; hypoactive sexual desire is treated by 41% of FECSM and dyspareunia by 17%. The participants were motivated by the pleasure of knowing new things and desire to understand and to help patients, whereas prestige, finances, and own sex lives are less important.

Conclusions

The first FECSM are very diverse in terms of age, culture, religion, and primary specialty. Their practice is strongly influenced by their primary specialty, and this needs to be taken into account in future development of the speciality.
Discourses on Language and Citizenship in Europe
Authors: Horner Kristine
Published: April 2015

This paper provides an overview of research on discourses on language and citizenship in contemporary Europe. Particular attention is given to the implementation of language requirements and/or formalized language testing for citizenship procedures that have become widespread since the turn of the 21st century. Scholars have focused on the discursive justification of these shifts in language policy and they have analyzed related discourses on diversity, cohesion and integration in multiple European Union member‐states. This paper underlines the need for further engagement with the concept of linguistic authority and it calls for research that explores the negotiation and contestation of these policies from ‘top‐down’ and ‘bottom‐up’ perspectives in a wider range of European Union member‐states.
The Relationship Between Task Difficulty and Second Language Fluency in French: A Mixed Methods Approach
Authors: Préfontaine Yvonne , Kormos Judit
Published: April 2015

While there exists a considerable body of literature on task‐based difficulty and second language (L2) fluency in English as a second language (ESL), there has been little investigation with French learners. This mixed methods study examines learner appraisals of task difficulty and their relationship to automated utterance fluency measures in French under three different task conditions. Participants were 40 adult learners of French at varying levels of proficiency studying in a university immersion context in Québec. Appraisal of task difficulty was assessed quantitatively by participants' self reports in response to a five‐item questionnaire and qualitatively by retrospective interviews. Utterance fluency was operationalized by four temporal variables and measured by Praat, a speech analysis software program. Across tasks, the quantitative results indicate that appraisals of lexical retrieval difficulty and fluency difficulty were most strongly related to perceived overall task difficulty. The qualitative analysis shows how L2 speakers evaluated the difficulty of each task as well as the features that either contributed to or limited their L2 fluency. Students' fluency in performing the three tasks was found to differ for articulation rate and average pause time, but not for pause frequency or phonation–time ratio.
Membrane‐associated transcription factor peptidase, site‐2 protease, antagonizes ABA signaling in Arabidopsis
Authors: Zhou Shun‐Fan , Sun Le , Valdés Ana Elisa , Engström Peter , Song Ze‐Ting , Lu Sun‐Jie , Liu Jian‐Xiang
Published: April 2015

Abscisic acid plays important roles in maintaining seed dormancy while gibberellins (GA) and other phytohormones antagonize ABA to promote germination. However, how ABA signaling is desensitized during the transition from dormancy to germination is still poorly understood.

We functionally characterized the role of membrane‐associated transcription factor peptidase, site‐2 protease (S2P), in ABA signaling during seed germination in Arabidopsis.

Genetic analysis showed that loss‐of‐function of S2P conferred high ABA sensitivity during seed germination, and expression of the activated form of membrane‐associated transcription factor bZIP17, in which the transmembrane domain and endoplasmic reticulum (ER) lumen‐facing C‐terminus were deleted, in the S2P mutant rescued its ABA‐sensitive phenotype. MYC and green fluorescent protein (GFP)‐tagged bZIP17 were processed and translocated from the ER to the nucleus in response to ABA treatment. Furthermore, genes encoding negative regulators of ABA signaling, such as the transcription factor ATHB7 and its target genes HAB1, HAB2, HAI1 and AHG3, were up‐regulated in seeds of the wild‐type upon ABA treatment; this up‐regulation was impaired in seeds of S2P mutants.

Our results suggest that S2P desensitizes ABA signaling during seed germination through regulating the activation of the membrane‐associated transcription factor bZIP17 and therefore controlling the expression level of genes encoding negative regulators of ABA signaling.
Imaging of cerebrovascular disorders: precision medicine and the collaterome
Authors: Liebeskind David S , Feldmann Edward
Published: April 2015

Imaging of stroke and neurovascular disorders has profoundly enhanced clinical practice and related research during the last 40 years since the introduction of computed tomography (CT) and magnetic resonance imaging (MRI) enabled mapping of the brain. We highlight recent advances in neurovascular imaging. We describe how the convergence of readily available data and new clinical trial paradigms will recast our methods for studying the neurovascular patient. The application of a precision medicine approach to the collaterome, a comprehensive synthesis of neurovascular pathophysiology, will entail novel methods for clinical trial randomization, collection of routine and clinical trial imaging results, data archiving, and analysis.
Zooplankton eat what they need: copepod selective feeding and potential consequences for marine systems
Authors: Meunier Cédric L. , Boersma Maarten , Wiltshire Karen H. , Malzahn Arne M.
Published: April 2015

Herbivores are generally faced with a plethora of resources which differ in quality. Therefore, they should be able to select foods which most closely match their metabolic needs. Here, we tested the hypothesis that copepods of the species Acartia tonsa select prey cells based on quality differences within prey species. We assessed age‐specific variation in feeding behaviour and evaluated the potential consequences of such variation for nutrient cycles. Nauplii (young) stages characterized by a low nitrogen to phosphorus (N:P) ratio in their body tissue selected for phosphorus‐rich food, while older copepodite stages with higher body N:P selected for nitrogen‐rich food. Further, the analysis of a 35‐year data set in the southern North Sea revealed a positive correlation between the abundance of nauplii and the ratio of dissolved inorganic N:P, thus suggesting that P‐availability for primary producers declines with the population densities of nauplii. Our findings demonstrate that a combination of stage‐specific selective feeding and body stoichiometry has the potential to affect cycling of limiting nutrients when consumer populations change in composition.
Right‐sided hepatic hernia of normal left lobe resembling cardiac tumor
Authors: Ono Hiroshi , Nagamine Hiroki , Toyoda Akifumi , Shimizu Nobutaka , Katori Tatsuo , Sugiyama Masahiko
Published: April 2015

A 3‐year‐old boy was referred for cardiac tumor diagnosed on transthoracic echocardiography (TTE) at another hospital. The tumor appeared to be in the right atrium and obstructed inferior vena cava flow. TTE, enhanced computed tomography (CT) and angiography were done to confirm diagnosis. Subsequently, cardiac tumor was ruled out and he was diagnosed with a very rare condition of hepatic hernia containing a normal left lobe. When cardiac tumor is suspected in the right atrium on the basis of TTE, enhanced CT or magnetic resonance imaging should be done for definitive diagnosis.
Pediatric patients with pheochromocytoma: Experience of a tertiary health center
Authors: Eren Erdal , Saglam Halil , Caliskan Yusuf , Kiristioglu Irfan , Tarim Omer
Published: April 2015

Background

The aim of this retrospective study was to investigate pheochromocytoma (pheo), which is a rare endocrine tumor in the pediatric population.

Methods

The medical records of five children with pheo were studied. The age, gender, clinical presentation, family history, physical findings, coexisting pathology, laboratory evaluation, surgical treatment, and postoperative course were investigated.

Results

The patients were four girls and one boy with a mean age of 13.2 years (range, 9.57–15.95 years). None of the patients had paroxysmal hypertension and one had normal blood pressure. No malign pheo was identified. Mean height and weight standard deviation scores (SDS), body mass index (BMI), and BMI SDS were −0.24, 0.04, 20.9 kg/m2, and 0.20 at the time of diagnosis, and 0.03, 0.43, 23.8 kg/m2 and 0.49 1 year after operation, respectively. BMI increased significantly after operation. Three patients had normal epinephrine and metanephrine, but elevated norepinephrine and normetanephrine on 24 h urine. Vanillylmandelic acid on 24 h urine sample was elevated in all patients. Ultrasonography failed to visualize tumors in two patients with bilateral pheo. One patient had postoperative severe hypotension. Insulin resistance associated with severe acanthosis nigricans observed in one patient regressed postoperatively.

Conclusions

Pheo in children may present with different symptoms and findings. Decreased catecholamine in the postoperative period may lead to weight gain.
Elective Patient Admission and Scheduling under Multiple Resource Constraints
Authors: Barz Christiane , Rajaram Kumar
Published: April 2015

We consider a patient admission problem to a hospital with multiple resource constraints (e.g., OR and beds) and a stochastic evolution of patient care requirements across multiple resources. There is a small but significant proportion of emergency patients who arrive randomly and have to be accepted at the hospital. However, the hospital needs to decide whether to accept, postpone, or even reject the admission from a random stream of non‐emergency elective patients. We formulate the control process as a Markov decision process to maximize expected contribution net of overbooking costs, develop bounds using approximate dynamic programming, and use them to construct heuristics. We test our methods on data from the Ronald Reagan UCLA Medical Center and find that our intuitive newsvendor‐based heuristic performs well across all scenarios.
Command without control: The case of China's environmental target system
Authors: Kostka Genia
Published: April 2015

In the existing literature there is general agreement that the effectiveness and efficiency of command and control instruments versus market‐based instruments is highly context specific. A country's particular regulatory environment and state capacity, as well as the features of given environmental problems, play an important role in ascertaining what the “right” set of policy instruments for environmental management might be. This article examines how command and control instruments are used as an environmental enforcement mechanism in China's authoritarian state. Based on extensive fieldwork, this paper shows that the reliance on binding environmental targets as the main domestic policy instrument in China has generated numerous undesirable consequences. While China's target‐based approach to implementation has incentivized local officials to strictly enforce environmental mandates, there are numerous shortcomings in the system. In particular, target rigidity, cyclical behaviour, poor data quality, and the absence of an independent monitoring agency have generated adverse effects and contribute to a yawning gap between regulatory goals and outcomes. The paper concludes that binding environmental targets as the main command–control instrument in China can be more accurately described as “command without control” as the target‐setting central government does not exercise a high degree of control over implementation and monitoring processes. But command and control instruments can be suited for managing “first‐generation” environmental problems and addressing environmental issues that have easily identifiable pollution sources and which are easy to verify.
The Unscientific Determinants of Voting on a Controversial Scientific Issue: An Evaluation of Biofuels Policy in the U.S. Congress
Authors: Ralston Jonah J.
Published: April 2015

Whether allegiance to party or the preferences of constituents are most important in an elected representative's voting decision has been a long‐running question in political science. This study contributes to this debate through an evaluation of biofuels policy in the U.S. Congress. Results indicate that in this policy area the House and Senate balance these influences differently, with partisanship playing a significant role in the House but not in the Senate. Analysis of voting on this issue indicates that there are important distinctions between how a legislator views the overall partisan preferences of constituents in their district or state versus how they view the interests of particular groups of constituents; when the concentration of agricultural interests in a legislator's district or state is great enough, it can override the effects of party for this issue, which suggests that legislators are especially concerned with specific constituency groups in their district or state that would stand to gain or lose from a policy. The proposition that a legislator is most likely to do that which benefits him or her most regardless of the available science relevant to a policy is a useful starting point for understanding what has been found in this research project.
On the threshold: older people's concerns about needs after discharge from hospital
Authors: Gabrielsson‐Järhult Felicia , Nilsen Per
Published: April 2015

Discharge from hospital is often strenuous for older people and requires adjustments from living an independent life to being in need of care and support. This study aims to explore older people's concerns about their needs after discharge. Twenty‐seven observations recorded at hospital discharge planning meetings were analysed with content analysis. An overarching theme emerged: being in a life transition, which reflected the older person's vulnerable and ambiguous situation in the discharge process. The theme was developed from three categories: obtaining a secure life situation, need of continuous care and support, and influencing and regaining independence. The findings highlight that older patients want to influence their care after discharge. They strive to regain independence and express their concerns about how to obtain a secure life situation through care organised to fit their individual needs. Knowledge about older people's concerns is important for healthcare providers and social workers involved in planning and individualised care and services.
Gilbert‐type deltas recording short‐term base‐level changes: Delta‐brink morphodynamics and related foreset facies
Authors: Gobo Katarina , Ghinassi Massimiliano , Nemec Wojciech
Published: April 2015

Gilbert‐type deltas are sensitive recorders of short‐term base‐level changes, but the delta‐front record of a base‐level rise tends to be erased by fluvial erosion during a subsequent base‐level fall, which renders the bulk record of base‐level changes difficult to decipher from the delta‐front deposits. The present detailed study of three large Pleistocene Gilbert‐type deltas uplifted on the southern coast of the Gulf of Corinth, Greece, indicates a genetic link between the delta‐front morphodynamic responses to base‐level changes and the delta‐slope sedimentation processes. Sigmoidal delta‐brink architecture signifies a base‐level rise and is accompanied by a debrite‐dominated assemblage of delta foreset deposits, thought to form when the aggrading delta front stores sediment and undergoes discrete gravitational collapses. Oblique delta‐brink architecture tends to be accompanied by a turbidite‐dominated assemblage of foreset deposits, which are thought to form when the delta‐front accommodation decreases and the sediment carried by hyperpycnal effluent bypasses the front. This primary signal of the system response to base‐level changes combines further with the secondary ‘noise’ of delta autogenic variation and possible allogenic fluctuations in fluvial discharge due to regional climatic conditions. Nevertheless, the evidence suggests that the facies trends of delta foreset deposits may be used to decipher the delta ‘hidden’ record of base‐level changes obliterated by fluvial topset erosion. Early‐stage bayhead deltas may be an exception from the hypothetical model, because their narrow front tends to be swept by river floods irrespective of base‐level behaviour and their subaqueous slope deposits are thus mainly turbidites.
Clinical characteristics of human immunodeficiency virus patients being referred for liver transplant evaluation: a descriptive cohort study
Authors: Martel‐Laferrière V. , Michel A. , Schaefer S. , Bindal S. , Bichoupan K. , Branch A.D. , Huprikar S. , Schiano T.D. , Perumalswami P.V.
Published: April 2015

Background

Liver transplantation (LT) is a treatment option for select human immunodeficiency virus (HIV)‐infected patients with advanced liver disease. The aim of this study was to describe LT evaluation outcomes in HIV‐infected patients.

Methods

All HIV‐infected patients referred for their first LT evaluation at the Mount Sinai Medical Center were included in this retrospective, descriptive cohort study. Multivariable logistic regression was used to identify factors independently associated with listing.

Results

Between February 2000 and April 2012, 366 patients were evaluated for LT, with 66 (18.0%) listed for LT and 300 (82.0%) not listed. Fifty‐one patients (13.9%) died before completing evaluation and 85 (23.2%) were too early for listing. Reasons patients were declined for listing were psychosocial (15.8%), HIV‐related (10.4%), loss to follow‐up (9.6%), surgical/medical (6.0%), liver‐related (4.4%), patient choice (3.4%), and financial (1.6%). Listed patients were more likely to have hepatocellular carcinoma (HCC) (43.1% vs. 17.1%; P < 0.0001) and less likely to have hepatitis B (6.2% vs. 15.7%; P = 0.04) or a psychiatric history (19.7% vs. 35.2%; P = 0.02) than those not listed. In multivariable analysis, HCC (odds ratio [OR] 5.79; 95% confidence interval [95% CI]: 2.97–11.28), model for end‐stage liver disease (MELD) score at referral (OR 1.06; 95% CI 1.01–1.11), and hepatitis B (OR 0.26; 95% CI 0.08–0.79) were associated with listing.

Conclusion

MELD score and HCC were positive predictors of listing in HIV‐infected patients referred for LT evaluation and, therefore, timely referrals are vital in these patients. As MELD is a predictor for death while undergoing evaluation, rapid evaluation should be performed in HIV‐infected patients with a higher MELD score.
Pyogranulomatous panophthalmitis with systemic coronavirus disease in a domestic ferret (Mustela putorius furo)
Authors: Lindemann Dana M. , Eshar David , Schumacher Loni L. , Almes Kelli M. , Rankin Amy J.
Published: April 2015

A 15‐month‐old spayed female ferret (Mustela putorius furo) presented for lethargy and weight loss of 2 weeks duration. Upon physical examination, a 2‐mm‐diameter focal area of opacity was noted in the left cornea. In addition, the ferret was quiet, in poor body condition, and dehydrated. A complete blood count and plasma biochemistry revealed a severe nonregenerative anemia, azotemia, hyperproteinemia, hypoalbuminemia, and mild hyperphosphatemia and hyperchloremia. Urinalysis revealed hyposthenuria. Whole body radiographs showed multifocal thoracic nodular disease, splenomegaly, and renomegaly. Abdominal ultrasonography confirmed bilaterally enlarged kidneys, hypoechoic liver and spleen, and a caudal abdominal hypoechoic mobile nodule. The ferret was humanely euthanized, and a postmortem examination with subsequent histopathology showed multifocal necrotizing pyogranulomas in the lung, spleen, kidneys, mesenteric lymph nodes, and serosa of the duodenum. Pyogranulomatous panophthalmitis was diagnosed in the left eye. The multisystemic granulomatous lesions were suggestive of ferret systemic coronavirus (FRSCV). The presence of coronavirus in the left eye was confirmed by positive immunohistochemistry. Reverse transcriptase polymerase chain reaction (RT‐PCR) on formalin fixed paraffin embedded tissue from the lung, spleen, and kidney was negative for FRSCV and positive for ferret enteric coronavirus (FRECV). Systemic coronavirus disease in ferrets closely resembles feline infectious peritonitis (FIP) in domestic cats, which can manifest with anterior uveitis, chorioretinitis, optic neuritis, and retinal detachment. To the authors’ knowledge, this is the first report of ocular lesions in a ferret with systemic coronavirus disease, suggesting that ferrets presented with similar ocular lesions should also be evaluated for evidence of coronavirus infection.
On the distribution of Atkin and Elkies primes for reductions of elliptic curves on average
Authors: Shparlinski Igor E. , Sutherland Andrew V.
Published: April 2015

For an elliptic curve$E/\mathbb{Q}$without complex multiplication we study the distribution of Atkin and Elkies primes$\ell$, on average, over all good reductions of$E$modulo primes$p$. We show that, under the generalized Riemann hypothesis, for almost all primes$p$there are enough small Elkies primes$\ell$to ensure that the Schoof–Elkies–Atkin point-counting algorithm runs in$(\log p)^{4+o(1)}$expected time.
Realistic Geometry Based Feature Modeling of Complex Part and Its Application in Assembly Quality Analysis
Authors: Chan Qiu , Zhenyu Liu , Xiang Peng , Guifang Duan , Jianrong Tan
Published: April 2015

The product assembly quality is influenced by the coupling effect of multiscale geometric errors. Acquiring the influence of dimension, tolerance and microtopography on part surface quality is the key factor of improving prediction accuracy of product assembly quality. Since the current technology of part solid modeling is difficult to represent tolerance information and surface topography information in computer aided design (CAD) model uniformly, and the accuracy of product assembly simulation and analysis is reduced, the realistic geometry based feature modeling of complex part and its application in assembly quality analysis are studied in this paper. First of all, the novel concept of realistic geometry is proposed, which integrates several geometric elements such as ideal geometry, variational geometry, and fractal geometry. Then, the hierarchical representation model of realistic geometric feature information of complex part is established, and the concrete method and steps to generate the realistic geometric solid features of complex part are proposed. Finally, the efficiency and feasibility of the proposed theory in this paper are validated by assembly quality analysis of the guide rail and sliding table of the machine tool.
Vibro-Acoustic Response of Engineering Structures With Mixed Type of Probabilistic and Nonprobabilistic Uncertainty Models
Authors: Cicirello Alice , Langley Robin S.
Published: April 2015

The response of engineering structures is often sensitive to uncertainty in the system properties. The information on the uncertain parameters is frequently incomplete, limited to experts’ opinion, based on previous knowledge, or a combination of those. There have been recent advances in building mathematical models of structures, which combine nonparametric probabilistic and parametric (probabilistic or nonprobabilistic) models of uncertainty. Here, several strategies for establishing the response of random systems whose uncertainties are described by parametric probabilistic and nonprobabilistic approaches in combination with a nonparametric probabilistic approach are presented. The proposed strategies are illustrated by analyzing a built-up plate structure.
Stall Control
Authors: Drabek S.
Published: April 2015

Compressor stall has had an increasing effect through the years upon gas turbine controls. The general problem was reasonably well known in the first decade of jet engine history after the “Whittle Engine”. The scheduling approach to the control of compressor stall established during this time has become rooted throughout the industry. On the other hand, an idealized approach based on sensing incipient stall remains an intriguing challenge.
Gas-Turbine-Exhaust Heat-Recovery Cycle
Authors: Morris G. L.
Published: April 2015

This paper is based on an operating industrial installation that the author’s company has engineered and constructed. It presents the various studies made by the engineers to arrive at the best all around solution, based on installed cost, ease of operation, simplicity, and over-all cycle thermal efficiency. Major elements of the installation are as follows: 1) Two 7500-hp simple-cycle gas turbines for driving process equipment. 2) Two 30,000-lb/hr watertube, two-drum, pressurized recovery boilers complete with a stack-type economizer, for heating feedwater for the recovery boiler and power boiler plus a separate economizer for process feedwater heating. 3) Two 40,000-lb/hr watertube, two-drum, balanced-draft power boiler capable of using either air or turbine exhaust gas for combustion air.
Gas-Turbine Drives for a Fluid Catalytic-Cracking Unit
Authors: Boatright James A.
Published: April 2015

This paper presents a unique application of two 14,200-hp gas turbines and their associated waste heat-recovery boilers in a refinery modernization program. It summarizes economics, design, and operating experience. Special emphasis is placed on three unusual features: (1) oversized starting turbines used as helpers; (2) control of two drivers with one governor; and (3) use of gas-turbine exhaust as combustion air, backed up by a forced-draft fan running at full speed against a closed damper.
Total Turbine Energy in Refrigeration Cycles
Authors: Robinson S. T. , Glessner J. W.
Published: April 2015

The means of using total energy from a gas-turbine engine in various refrigeration systems are reviewed. Combinations of heating and cooling or electric power generation and cooling are discussed as well as combined centrifugal and absorption refrigeration systems. The economics of gas-burning turbine engines are investigated and shown to be attractive in these applications.
Development of the Combustion System for the AiResearch TPE331 Turboprop Engine
Authors: Haasis J. M.
Published: April 2015

The AiResearch TPE turboprop engine is a single-shaft gas turbine rated at 605 shp. The combustion system of this engine is described, and the design considerations and development of the combustion system are discussed.
Design Aspects of Power Plants for V/STOL Aircraft
Authors: Coplin J. F.
Published: April 2015

Thrust in execess of that required for cruise and flight maneuvering is necessary to provide an aircraft with a VTOL capability. The extra thrust may be obtained by enlarged cruise engines with thrust vectoring or by retaining the optimum-size cruise engine possibly with thrust vectoring and adding a lift power plant in the form of lift jets or lift fans. A brief outline of extensive experience with lift jets, thrust vectoring, and lift fans is given and the importance of this background in making it possible to design more advanced engines which will satisfactorily meet practical operational requirements is brought out. Experience in two generations of lift-jet flight testing has shown many important areas where specal features must be incorporated in the design from the beginning to achieve high thrust for a compact volume, light weight, and high integrity in the relatively severe environment in which the lift jet has to operate. Examples are cited. The relative importance of thrust/volume and thrust/weight ratio is shown with reference to VTOL strike and transport aircraft. An integrated concept, using compact lift jets for VTOL strike aircraft and compact low-efflux-velocity lift fans using the same engine as a gas generator, is briefly noted.
Development of Inlet for an Axial Compressor
Authors: Reisweber R. C.
Published: April 2015

In development of an axial-flow boiler supercharger, a test program on the compressor inlet was carried out. Tests were run using a test compressor aerodynamically identical to the first three stages of the supercharger compressor. Prototype compressor inlet was compared to an axial inlet, and also to several modified inlets. While the prototype inlet showed considerably more distortion ahead of the inlet guide vanes than the axial inlet, the inlet guide vanes removed most of the distortion. As a result, overall performance of all inlet configurations was essentially the same.
Hydromechanical Fuel Control for Portable Gas Turbine Generator Sets
Authors: Parker G. E.
Published: April 2015

Controls for small lightweight gas turbines present some unique design problems. The requirements for small size, light weight, ability to rotate at high speeds to save reduction gearing, and low production cost conflict with the requirements for reasonably accurate control of very small fuel flows and the scheduling of a wide range of hydrocarbon fuels over a wide range of ambient temperatures. This paper discusses in some detail the design of such a control and the satisfactory results obtained.
Gas Turbines in the Royal Navy, 1965–1969
Authors: Morgan S. G. , Lamport A. W. , Smith A. J. R.
Published: April 2015

This paper deals with the Royal Navy’s experience with marine gas turbines during the past four years. The Royal Navy now has a large number of semi-industrial type gas turbines at sea and is currently engaged upon the development and sea trials of aircraft type turbines for major warship propulsion, drawing on its experience with the engines of the “Brave” class fast patrol boats, which have had to be overcome on the various engines and in the ship installations are discussed.
Reduction of Low Power Smoke Emission From an Industrial Gas Turbine Engine
Authors: Koblish T. R. , Schwartz H. R.
Published: April 2015

In certain applications, gas turbine engines used for stationary or marine power must on occasion operate in a power range far below normal engine idle speed. At this low power range, conditions are least favorable for good combustor performance. As a result, operation at these conditions with heavy distillate fuels may result in the emission of white acrid smoke from the engine exhaust stacks. Concern over this situation by the authors’ company prompted the initiation of a burner rig program to determine the effect of fuel atomization and stratification on combustion stability, combustion efficiency, and quantity of “white” smoke emission. The program test results indicated that the white smoke at low idle conditions can be eliminated or at least substantially reduced, with no deterioration in performance or smoke at high power, by increasing the local fuel air ratio within the burner front end and by improving fuel atomization.
Experimental Performance in Annular Cascade of Variable Trailing-Edge Flap, Axial-Flow Compressor Inlet Guide Vanes
Authors: Okiishi T. H. , Junkhan G. H. , Serovy G. K.
Published: April 2015

Aerodynamic performance of a variable-geometry axial-flow compressor inlet guide vane configuration for a gas turbine unit was determined in a series of annular cascade tests. The variable-geometry vanes used uncambered, symmetrical airfoil sections as the basic blade profile with the rear 70 percent of the vane profile movable as a trailing-edge flap. Vane flap mechanical setting angles of 0 to 50 deg measured from the axial direction were possible, and performance parameters were determined over this range of angles. Turning angles followed a general trend obtained with Carter’s rule for accelerating cascades with the presently measured values tending to be lower than those obtained with Carter’s rule at higher setting angles. For large camber angles (greater than 35 deg) zero-incidence blade element total-pressure loss coefficients for the 50 percent passage location of the flapped vanes tested were higher than those that might have been obtained with a continously cambered vane row of the same solidity and camber.
Precision Molding of Advanced Fiber Structures
Authors: Leslie J. C.
Published: April 2015

New technologies are being developed to meet the special problems encountered in molding precision parts from highly anisotropic composite materials comprised of advanced fibers and resin. Design considerations require many different ply orientations to fully utilize superior fiber mechanical properties. Coincident with their directional mechanical properties, composites exhibit a similar degree of anisotropy in other physical properties. Measured thermal coefficients of expansion for graphite/epoxy laminates are of −0.5 × 10−6 in/in/F parallel to the fiber axis and 39 × 10−6 in/in/F perpendicular to the fiber axis. Since composite parts are cured at elevated temperatures, this anisotropy produces appreciable residual stress as well as stability problems in dimensions of the finished part. Examples of these problems are presented. In addition to specific problem areas, the many aspects of achieving a true precision molding are reviewed. Specifically, the fabrication variables associated with resin and fiber selection, consolidation, and cure procedures are discussed.
American Airlines’ Data Reduction Experience With Electronic Maintenance Recorders
Authors: Pauliny Steve
Published: April 2015

This paper describes American Airlines’ data reduction experience in a program in which electronic engine maintenance recorders were installed in 15 BAC 1-11 aircraft. The maintenance recorder system is briefly outlined. Elements of the data and its reduction through software programs leading to computer fault analysis are portrayed. Significant electronic maintenance recorder experience is summarized and some economic projections on the Jumbo Jets are made, based on this experience.
Design Concepts for Fiber-Metal Matrix Composites for Advanced Gas Turbine Blades
Authors: Weeton J. W.
Published: April 2015

Advances in gas turbine technology depend in large measure upon advances in materials technology. Arbitrary stringent criteria for room temperature spefific strengths and moduli and for 2000 F, 1000-hr stress-rupture strength were chosen for design goals. Required fiber properties to meet these criteria were calculated for fiber and matrix material combinations of widely ranging densities. It was demonstrated, on a first approximation basis, that numerous composite materials with specific tensile or stress-rupture strengths, and specific moduli superior to those of conventional materials can be “designed” from fiber and matrix materials available today.
Gas Turbine - Steam Turbine Power Plant for Production of Electricity and Process Steam for a Chemical Industry
Authors: Sauveniere J. , Vidossich G.
Published: April 2015

For the extension of a chemical plant it was necessary to install an additional process steam generating unit. This paper presents the selected plant. In order to obtain the best efficiency, steam and electricity production have been combined using a gas turbine and a recovery boiler. An added helper steam turbine raised even more the electricity generation efficiency. Components of the plant, cycle arrangement and performances are described. Actual performance data are not presented in this report because they were not available at the time of its printing.
A Feasibility Study of a High-Speed Combustor for Turbomachine Applications
Authors: Fruchtman Irving
Published: April 2015

The theoretical analysis, design, and experimental study of a high-speed combustion chamber are described. Such a burner may be used when the compressor outflow speed is so high that diffusion to the usual burner entrance conditions presents severe loss penalties. The study showed for a small mass flow-high pressure ratio turbomachine, that combined diffusor and combustor losses are minimum for a burner entrance Mach number of about 0.5. To design the burner a finite rate chemistry and turbulent mixing computer program was used; the combustor modeling and flame spread predictions are discussed. A series of experiments are described and burner pressure loss and temperature profiles are shown over a range of burner air-flow conditions.
Sound Transmission and Suppression in Turbomachinery Ducts
Authors: Benzakein M. J. , Zwick J. W.
Published: April 2015

The authors present analysis of the transmission and radiation of turbomachinery generated noise in fans and compressor ducts. Based on a numerical solution of the three-dimensional wave equation in a homogeneous medium flowing in ducts of arbitrary shape, the analysis is an extension of the analytical treatment of noise generation in turbomachinery presented in references (1) and (2). The theoretical noise transmission model permits the evaluation of fan/compressor noise suppressor (acoustic treatment) configurations in the presence of spinning modes in a moving medium. Results of barometric calculations are presented for a stationary medium; experimental verifications of the analysis are included; and the effects of turbomachinery duct lengths and shapes on the transmission of sound are discussed. Also presented are the results of parametric studies on the effects of liner material location on sound suppression. The results indicate that optimum sound suppression can be achieved with the basic knowledge of the duct wave propagation phenomena.
Optimum Cycle Parameters for Turbofan Engines
Authors: Moffatt W. C.
Published: April 2015

This paper presents closed-form solutions for optimum compressor pressure ratio, bypass ratio and fan pressure ratio, given the turbine inlet temperature, component efficiencies and flight Mach number for a turbofan engine. In addition a simple procedure is outlined for obtaining the optimum combination of these quantities and a sample calculation is included. The optimum condition is defined as that which maximizes the specific thrust (thrust per pound per second of air flow through the gasifier) of the engine. The effects of differing gas properties in different portions of the engine are included in the analysis.
Performance Evaluation of a Gas Turbine Drive Industrial Building Cooling System
Authors: Sundeen E. E.
Published: April 2015

The text deals with an evaluation of a gas turbine drive refrigeration system after four years of operation. Comparison is made of actual performance, operating, and maintenance costs with original system design concept, goals, and objectives.
Gas Turbine Propulsion for High Utilization Cargo Ships
Authors: Daresta F. G. , Smith H. F.
Published: April 2015

Why choose the aircraft type gas turbine for ship propulsion? Initial cost, weight, space, floor area, engine room height, fuel cost, and other operating costs are the factors determining the selection of the propulsion plant. A comparison of these factors with regards to containerships and tankers is evaluated. It is evident from the results that total economics favors the aircraft type gas turbine power-plant.
Aircraft Turbine Engine Emissions and the Possibilities for Control
Authors: Gray Charles , Kittredge G. D.
Published: April 2015

The Environmental Protection Agency has completed a study of the impact of aircraft emissions on air quality and a study of the technological feasibility of controlling aircraft emissions including an analysis of the cost and time requirements of the various control approaches. The air quality study has determined the need for aircraft emission standards, and the control technology study has determined that control is feasible and cost effective given adequate development time.
Measuring the effects of spectral smearing and enhancement on speech recognition in noise for adults and children
Authors: Nittrouer Susan , Tarr Eric , Wucinich Taylor , Moberly Aaron C. , Lowenstein Joanna H.
Published: April 2015

Broadened auditory filters associated with sensorineural hearing loss have clearly been shown to diminish speech recognition in noise for adults, but far less is known about potential effects for children. This study examined speech recognition in noise for adults and children using simulated auditory filters of different widths. Specifically, 5 groups (20 listeners each) of adults or children (5 and 7 yrs), were asked to recognize sentences in speech-shaped noise. Seven-year-olds listened at 0 dB signal-to-noise ratio (SNR) only; 5-yr-olds listened at +3 or 0 dB SNR; and adults listened at 0 or −3 dB SNR. Sentence materials were processed both to smear the speech spectrum (i.e., simulate broadened filters), and to enhance the spectrum (i.e., simulate narrowed filters). Results showed: (1) Spectral smearing diminished recognition for listeners of all ages; (2) spectral enhancement did not improve recognition, and in fact diminished it somewhat; and (3) interactions were observed between smearing and SNR, but only for adults. That interaction made age effects difficult to gauge. Nonetheless, it was concluded that efforts to diagnose the extent of broadening of auditory filters and to develop techniques to correct this condition could benefit patients with hearing loss, especially children.
Vibration and sound radiation of an electrostatic speaker based on circular diaphragm
Authors: Chiang Hsin-Yuan , Huang Yu-Hsi
Published: April 2015

This study investigated the lumped parameter method (LPM) and distributed parameter method (DPM) in the measurement of vibration and prediction of sound pressure levels (SPLs) produced by an electrostatic speaker with circular diaphragm. An electrostatic speaker with push-pull configuration was achieved by suspending the circular diaphragm (60 mm diameter) between two transparent conductive plates. The transparent plates included a two-dimensional array of holes to enable the visualization of vibrations and avoid acoustic distortion. LPM was used to measure the displacement amplitude at the center of the diaphragm using a scanning vibrometer with the aim of predicting symmetric modes using Helmholtz equations and SPLs using Rayleigh integral equations. DPM was used to measure the amplitude of displacement across the entire surface of the speaker and predict SPL curves. LPM results show that the prediction of SPL associated with the first three symmetric resonant modes is in good agreement with the results of DPM and acoustic measurement. Below the breakup frequency of 375 Hz, the SPL predicted by LPM and DPM are identical with the results of acoustic measurement. This study provides a rapid, accurate method with which to measure the SPL associated with the first three symmetric modes using semi-analytic LPM.
Impulse response method for characterization of echogenic liposomes
Authors: Raymond Jason L. , Luan Ying , van Rooij Tom , Kooiman Klazina , Huang Shao-Ling , McPherson David D. , Versluis Michel , de Jong Nico , Holland Christy K.
Published: April 2015

An optical characterization method is presented based on the use of the impulse response to characterize the damping imparted by the shell of an air-filled ultrasound contrast agent (UCA). The interfacial shell viscosity was estimated based on the unforced decaying response of individual echogenic liposomes (ELIP) exposed to a broadband acoustic impulse excitation. Radius versus time response was measured optically based on recordings acquired using an ultra-high-speed camera. The method provided an efficient approach that enabled statistical measurements on 106 individual ELIP. A decrease in shell viscosity, from 2.1 × 10−8 to 2.5 × 10−9 kg/s, was observed with increasing dilatation rate, from 0.5 × 106 to 1 × 107 s−1. This nonlinear behavior has been reported in other studies of lipid-shelled UCAs and is consistent with rheological shear-thinning. The measured shell viscosity for the ELIP formulation used in this study [κs = (2.1 ± 1.0) × 10−8 kg/s] was in quantitative agreement with previously reported values on a population of ELIP and is consistent with other lipid-shelled UCAs. The acoustic response of ELIP therefore is similar to other lipid-shelled UCAs despite loading with air instead of perfluorocarbon gas. The methods described here can provide an accurate estimate of the shell viscosity and damping for individual UCA microbubbles.
Comparison between experimental and computational methods for the acoustic and thermal characterization of therapeutic ultrasound fields
Authors: Maruvada Subha , Liu Yunbo , Soneson Joshua E. , Herman Bruce A. , Harris Gerald R.
Published: April 2015

For high intensity therapeutic ultrasound (HITU) devices, pre-clinical testing can include measurement of power, pressure/intensity and temperature distribution, acoustic and thermal simulations, and assessment of targeting accuracy and treatment monitoring. Relevant International Electrotechnical Commission documents recently have been published. However, technical challenges remain because of the often focused, large amplitude pressure fields encountered. Measurement and modeling issues include using hydrophones and radiation force balances at HITU power levels, validation of simulation models, and tissue-mimicking material (TMM) development for temperature measurements. To better understand these issues, a comparison study was undertaken between simulations and measurements of the HITU acoustic field distribution in water and TMM and temperature rise in TMM. For the specific conditions of this study, the following results were obtained. In water, the simulated values for p+ and p− were 3% lower and 10% higher, respectively, than those measured by hydrophone. In TMM, the simulated values for p+ and p− were 2% and 10% higher than those measured by hydrophone, respectively. The simulated spatial-peak temporal-average intensity values in water and TMM were greater than those obtained by hydrophone by 3%. Simulated and measured end-of-sonication temperatures agreed to within their respective uncertainties (coefficients of variation of approximately 20% and 10%, respectively).