bluuebunny/crossref_metadata_2025 huggingface dataset:
Normative data for the Strengths and Difficulties Questionnaire for young children in Australia
Authors: Kremer Peter , de Silva Andrea , Cleary Joyce , Santoro Giuseppe , Weston Karen , Steele Emily , Nolan Terry , Waters Elizabeth
Published: April 2015

Aim

The aim of this study was to report normative data for the parent‐reported Strengths and Difficulties Questionnaire (SDQ) from a large population cohort of young children aged 4–6 years from Victoria, Australia, to establish age‐ and sex‐specific cut‐off values for future use, and to determine the scale reliability of the SDQ for children aged 4–6 years.

Methods

Parents of children (n = 53 372) entering their first year of school in Victoria in 2010 completed a survey via a 15‐page School Entrant Health Questionnaire reporting on the physical and emotional well‐being of their child (including the SDQ), use of child health and other support services, and a range of socio‐demographic variables. Reliability was assessed and norms generated. Appropriate cut‐off values for each SDQ scale and total difficulties scale were generated for each age group separately for each sex.

Results

The five scales of the SDQ and total difficulties scale generally had acceptable internal reliability. Mean SDQ scale scores differed for both sex and age, although only a narrow age range is examined in this study. Cut‐off values were marginally higher for girls (lower for prosocial) and generally increased with age.

Conclusions

This study has utilised a large Australian population sample of children to generate age‐ and sex‐specific cut‐off values that define SDQ scores as ‘normal’, ‘borderline’ or ‘abnormal’ for Australian children aged 4–6 years.
Prospective Evaluation of Postoperative Penile Rehabilitation: Penile Length/Girth Maintenance 1 Year Following Coloplast Titan Inflatable Penile Prosthesis
Authors: Henry Gerard D. , Carrion Rafael , Jennermann Caroline , Wang R.u.n.
Published: April 2015

Introduction

The most prevalent long-term complaint after successful inflatable penile prosthesis (IPP) surgery is reduction of penile length. The purpose of this study was to evaluate penile measurements in patients whose implantation experience included the aggressive new length measurement technique (NLMT) coupled with postoperative IPP rehabilitation (daily inflation) of the implant for 1 year. Moreover, we aimed to document objective data concerning dimensional changes of the phallus over time. Postoperative IPP rehabilitation has been discussed and presented at meetings, but no multi-institutional prospective data have been published.

Aim

Our goal was to assess results using the Coloplast Titan IPP, with NLMT, and postoperative rehabilitation.

Methods

After IRB approval, we conducted a prospective, three-center study of 40 patients who underwent IPP placement, with NLMT for end organ failure erectile dysfunction with the Coloplast Titan IPP. The patient was instructed to inflate daily for 6 months and then inflate maximally for 1–2 hours daily for 6–12 months. Fifteen penile measurements were taken before and immediately after surgery and at follow-up visits.

Main Outcome Measure

Penile length measurements after implantation compared with 12 months postimplantation.

Results

Penile measurement changes were statistically significantly improved at 12 months as compared with immediately postoperative and at 6 months. A total of 64.5% of subjects were satisfied with their length at 1 year, and 74.2% had perceived penile length that was longer (29%) or the same (45.2%) as prior to the surgery; 61.3% and 16.1% of subjects had increased and unchanged satisfaction, respectively, with penile length as compared with prior to IPP surgery. All but two subjects (93.4%) were satisfied with the overall function and dimensions of their IPP.

Conclusion

This study suggests using the Coloplast Titan IPP with aggressive cylinder sizing, and a postoperative penile rehabilitation inflation protocol may help optimize patient satisfaction and erectile penile measurements.
An accountability evaluation for the industry's responsible use of brand mascots and licensed media characters to market a healthy diet to American children
Authors: Kraak V. I. , Story M.
Published: April 2015

Corporate strategies that target children are controversial given the link between food marketing and childhood obesity. This case study explored diverse stakeholders' accountability expectations and actions for industry policies and practices that used popular cartoon brand mascots and media characters to promote food products to American children. We reviewed five electronic databases and Internet sources between January 2000 and January 2015. Evidence (n = 90) was selected based upon the Institute of Medicine's LEAD principles (i.e. locate, evaluate, assemble evidence to inform decisions) and organized into two tables: peer‐reviewed articles, books and grey‐literature reports (n = 34); and media stories, news releases and public testimony (n = 56). A four‐step accountability framework was used to evaluate accountability structures. The results showed that moderate progress was achieved by stakeholders to take and share the account, limited progress to hold industry and government to account, and limited progress to strengthen accountability structures. Between 2006 and 2015, the U.S. Children's Food and Beverage Advertising Initiative lacked clear policies for companies to use brand mascots and media characters on food packages, in merchandising, and as toy giveaways and premiums. Government, industry and civil society can substantially strengthen their accountability for these food marketing practices to ensure healthy food environments for children.
Children with Warts: A Retrospective Study in an Outpatient Setting
Authors: Kuwabara Anne M. , Rainer Barbara M. , Basdag Hatice , Cohen Bernard A.
Published: April 2015

Background

The purpose is to investigate the demographics and course of common warts in children in an outpatient setting.

Methods

A retrospective medical chart review and telephone survey study were completed on an outpatient cohort of children (0–17 yrs) with a clinical diagnosis of warts at a single‐center, university‐based pediatric dermatology practice. The main outcome measures included management, time to resolution, and associated factors of warts in children.

Results

Of the 254 patients we contacted, 214 agreed to participate in the survey. The most commonly involved sites were the hands and the head and neck area. Most children received some form of therapy, but it is unclear that any form of treatment altered the course. However, children with a medical history of childhood infections or more than one anatomic site had significantly greater risk of having a longer time to resolution.

Conclusion

Warts resolved in 65% of children by 2 years and in 80% within 4 years, regardless of treatment. With the exception of a history of childhood infections and having more than one anatomic site, time to resolution was not altered by wart or patient characteristics. Thus counseling without aggressive destructive treatment is a reasonable approach to managing warts in most children. Our findings will provide guidance in the process of shared decision making with parents and children.
Ethnicity and Occupational Pension Membership in the UK
Authors: Vlachantoni Athina , Feng Zhixin , Evandrou Maria , Falkingham Jane
Published: April 2015

Reflecting a relatively low‐value Basic State Pension, occupational pensions have historically been a key aspect of pension protection within Britain. Existing research shows that minority ethnic groups are less likely to benefit from such pensions and are more likely to face poverty in later life, as a result of the interaction of their labour market participation and pension membership patterns. However, the lack of adequate data on ethnic minorities has so far prevented the direct comparison of different ethnic groups, as well as their comparison to the White British group. Using data from the UK Household Longitudinal Study, this article explores patterns of employment and the odds ratios of membership in an employer's pension scheme among working‐age individuals from minority ethnic groups and the White British population, taking into account factors not used by previous research, such as one's migration history and sector of employment (public/private). The analysis provides new empirical evidence confirming that ethnicity remains a strong determinant of one's pension protection prospects through being in paid work, being an employee and working for an employer who offers a pension scheme. However, once an individual is working for an employer offering a pension scheme, the effect of ethnicity on that person's odds of being a member of that scheme reduces, except among Pakistani and Bangladeshi individuals for whom the differentials remain. The article also provides evidence on the pension protection of Polish individuals, a relatively ‘new’ minority group in the UK.
Teaching Multiple Modes of Representation in Middle‐School Science Classrooms: Impact on Student Learning and Multimodal Use
Authors: Nixon Ryan S. , Smith Leigh K. , Wimmer Jennifer J.
Published: April 2015

This quasi‐experimental study investigated how explicit instruction about multiple modes of representation (MMR) impacted grades 7 (n = 61) and 8 (n = 141) students’ learning and multimodal use on end‐of‐unit assessments. Half of each teacher's (n = 3) students received an intervention consisting of explicit instruction on MMR in science discourse, in addition to regular science instruction enhanced by a focus on MMR; comparison groups of students received regular science instruction. Three ordinary least squares regression models used student demographic variables and whether or not students received the intervention to predict students’ (a) gain scores on end‐of‐unit tests, (b) voluntary use of embedded MMR on unit tests, and (c) retention of science knowledge as measured by a state end‐of‐level criterion‐referenced assessment. Analyses showed that explicit instruction on MMR did not make a significant impact on student gain scores, the amount of embeddedness on unit tests, or end‐of‐level scores. However, Models 2 and 3 showed Hispanics and females used MMR more on end‐of‐unit tests than Whites or males, respectively, whether or not they received the intervention. Hispanics and females scored lower than Whites or males, respectively, on end‐of‐level, multiple‐choice assessments. Implications for classroom teachers and educational researchers in relation to these underserved populations are discussed.
Who is left behind on the road to universal facility delivery? A cross‐sectional multilevel analysis in rural Tanzania
Authors: Kruk Margaret E. , Hermosilla Sabrina , Larson Elysia , Vail Daniel , Chen Qixuan , Mazuguni Festo , Byalugaba Beatrice , Mbaruku Godfrey
Published: April 2015

Objectives

To examine factors associated with home delivery among women in Pwani Region, Tanzania, which has experienced a rapid rise in facility delivery coverage.

Methods

Cross‐sectional data from a population‐based survey of women residing in rural areas of Pwani Region were linked to health facility locations. We fitted multilevel logistic models to examine individual and community factors associated with home delivery.

Results

A total of 752 (27.95%) of the 2691 women who completed the survey delivered their last child at home. Women were less likely to deliver at home if they had any primary education [odds ratio (OR) 0.62; 95% confidence interval (CI): 0.50, 0.79], were primiparous (OR: 0.52; 95% CI: 0.37, 0.73), had more exposure to media (OR: 0.80; 95% CI: 0.66, 0.96) or had received more (OR: 0.78; 95% CI: 0.63, 0.96) or better quality antenatal care (ANC) services (OR: 0.48; 95% CI: 0.34, 0.67). Increased wealth was strongly associated with lower odds of home delivery (OR: 0.27; 95% CI: 0.18, 0.39), as was living in a village that grew cash crops (OR: 0.56; 95% CI: 0.35, 0.88). Farther distance to hospital, but not to lower level facilities, was associated with higher likelihood of home delivery (OR 2.49; 95% CI: 1.60, 3.88).

Conclusions

Poverty, multiparity, weak ANC and distance to hospital were associated with persistence of home delivery in a region with high coverage of facility delivery. A pro‐poor path to universal coverage of safe delivery requires a greater focus on quality of care and more intensive outreach to poor and multiparous women.
Building awareness to health insurance among the target population of community‐based health insurance schemes in rural India
Authors: Panda Pradeep , Chakraborty Arpita , Dror David M.
Published: April 2015

Objective

To evaluate an insurance awareness campaign carried out before the launch of three community‐based health insurance (CBHI) schemes in rural India, answering the questions: Has the awareness campaign been successful in enhancing participants’ understanding of health insurance? What awareness tools were most useful from the participants' point of view? Has enhanced awareness resulted in higher enrolment?

Methods

Data for this analysis originates from a baseline survey (2010) and a follow‐up survey (2011) of more than 800 households in the pre‐ and post‐campaign periods. We used the difference‐in‐differences method to evaluate the impact of awareness activities on insurance understanding. Assessment of usefulness of various tools was carried out based on respondents’ replies regarding the tool(s) they enjoyed and found most useful. An ordinary least square regression analysis was conducted to understand whether insurance knowledge and CBHI understanding are related with enrolment in CBHI.

Results

The intervention cohort demonstrated substantially higher understanding of insurance concepts than the control group, and CBHI understanding was a positive determinant for enrolment. Respondents considered the ‘Treasure‐Pot’ tool (an interactive game) as most useful in enhancing awareness to the effects of insurance.

Conclusions

We conclude that awareness‐raising is an important prerequisite for voluntary uptake of CBHI schemes and that interactive, contextualised awareness tools are useful in enhancing insurance understanding.
Noninvasive fetal genotyping of human platelet antigen‐1a using targeted massively parallel sequencing
Authors: Wienzek‐Lischka Sandra , Krautwurst Annika , Fröhner Vanessa , Hackstein Holger , Gattenlöhner Stefan , Bräuninger Andreas , Axt‐Fliedner Roland , Degenhardt Jan , Deisting Christina , Santoso Sentot , Sachs Ulrich J. , Bein Gregor
Published: April 2015

BACKGROUND

Fetal human platelet antigen (HPA) genotyping is required to determine whether the fetus is at risk and whether prenatal interventions to prevent fetal bleeding are required in pregnant women with a history of fetal and neonatal alloimmune thrombocytopenia (FNAIT). Methods for noninvasive genotyping of HPA alleles with the use of maternal plasma cell‐free DNA were published recently but do lack internal controls to exclude false‐negative results.

STUDY DESIGN AND METHODS

Cell‐free DNA was isolated from plasma of four pregnant women with a history of FNAIT caused by anti‐HPA‐1a and controls. A primer panel was designed to target sequences flanking single‐nucleotide polymorphisms (SNPs)/exonic regions ofITGB3(HPA‐1),ITGA2B(HPA‐3),ITGA2(HPA‐5),CD109(HPA‐15),RHD,RHCE,KEL,DARC,SLC14A1,GYPA,GYPB, andSRY. These regions and eight anonymous SNPs were massively parallel sequenced by semiconductor technology.

RESULTS

The mean (±SD) number of reads for targeted SNPs was 5255 (±2838). Fetal DNA was detected at a median of 4.5 (range, 2‐8) polymorphic loci. The mean fractional fetal DNA concentration in cell‐free maternal plasma was 8.36% (range, 4.79%‐15.9%). For HPA‐1, nonmaternalITGB3sequences (c.176T, HPA‐1a) were detected in all HPA‐1ab fetuses. One HPA‐1bb fetus was unequivocally identified, showing the pregnancy was not at risk of FNAIT.

CONCLUSION

We have successfully established massively parallel sequencing as a novel reliable method for noninvasive genotyping of fetal HPA‐1a alleles. This technique may also allow the safe detection of other fetal blood group polymorphisms frequently involved in FNAIT and hemolytic disease of the newborn.
Finite Element Analysis on Chattering in Cold Rolling and Comparison With Experimental Results
Authors: Mehrabi Reza , Salimi Mahmoud , Ziaei-Rad Saeed
Published: April 2015

In this paper, the chattering phenomenon in cold rolling is investigated in reference to the finite element method (FEM). The structure of the mill stand is modeled as a system of linear springs and lumped masses while the rolling process is modeled utilizing an implicit FEM. Assembling the two models makes it possible to detect the chatter during the rolling process. The assembled model is capable of perceiving variations in forces generated during the process that deflects the structure of the mill leading to variations at the roll gap and the roll speed. The influences of some rolling parameters on chatter vibration are investigated. Predicted values of the model are in good agreement with that of the experiments as well as the values obtained by other researchers.
Effects of Vaneiess Diffuser Geometry on Flow Instability in Centrifugal Compression Systems
Authors: Abdelhamid A. N.
Published: April 2015

Experiments were conducted to determine the effects of vaneless diffuser radius ratio on the occurrence of self-excited flow oscillations in a centrifugal compression system. Analysis of the results indicated the successive occurrence of two types of diffuser rotating pressure patterns as the flow rate in the system was gradually decreased. The rotational speed of the latter pattern was higher than that of the initial pattern and both speeds varied inversely with diffuser radius ratio. The critical flow angle at which each pattern was first observed increased with diffuser radius ratio. However, for diffuser radius ratio equal to and larger than 1.75 the rate of change of the critical angle with radius ratio decreased significantly. The results also showed that the minimum diffuser radius ratio necessary for self excitation of each pattern were different. Occurrence of two rotating pressure patterns confirms analytical results presented in a previous investigation.
New Features in the Design of Axial-Flow Compressors With Tandem Blades
Authors: Bammert K. , Staude R.
Published: April 2015

A multitude of examinations and studies of compressor blades with 100 percent reaction have shown that tandem blades can advantageously be used in stationary industrial axial flow compressors, designed for applications in the chemical, iron and steel industries. Because there are no limitations for axial flow compressors with tandem blades, this type of compressor can operate up to maximum pressure ratios of 10 for suction volume flow of about 600,000 m3 /h. In particular, the handling of light gases, such as helium, leads also to large sizes. Based on measurements taken on a four-stage experimental compressor, criteria are developed for the design of axial flow compressors with tandem blades. The basic concept of a multi-stage industrial compressor provides for the combined arrangement of compressor stages of single and tandem-cascade design. This permits an optimum performance to be achieved at a considerable reduction of the constructional expenditure.
A Development of the Fuel Atomizing Device Utilizing High Rotational Speed
Authors: Morishita T.
Published: April 2015

A fuel atomizing device was developed for a combustor of a small gas turbine engine. The device is a rotary atomizer in which liquid fuel is supplied through a stationary nozzle onto a specially shaped disc rotating with a high tangential velocity (over 200 m/sec). The rotary atomizer has shown remarkably good atomization characteristics when used in the engine. The mean droplet size of the atomizer is explained by the following equation for water: SMD = 0.033 • U−0.7 • Q0.2 • D0.3. The SMD for fuel can be evaluated by the correlation of: SMD∞(σ/ρ)0.5. The performance together with its configurations will be discussed in detail.
Impacts of Broadened-Specification Fuels on Aircraft Turbine Engine Combustors
Authors: Bahr D. W.
Published: April 2015

In the future, aircraft turbine engines may be required to accommodate fuels with lower hydrogen contents, fluidity/volatility characteristics and thermal stability ratings than those of present-day jet fuels. The key results of several investigations conducted to quantify the impacts of such fuel property changes on the performance, pollutant emission and durability characteristics of aircraft turbine engine combustors are reviewed. These results were obtained in both component and engine tests of the current production combustors used in the CF6-6, CF6-50, F101/CFM56 and J79/CJ805 engines. Based on these results, it is concluded that the most significant concerns associated with such fuel property changes are decreased combustor life, decreased ground starting/altitude relight capabilities and increased fuel injector gumming/coking tendencies. The combustor design improvements that appear to be needed to permit the use of jet fuels of significantly lower quality than present-day fuels are also reviewed.
Unbalance Response of a Two Spool Gas Turbine Engine With Squeeze Film Bearings
Authors: Gunter E. J. , Li D. F. , Barrett L. E.
Published: April 2015

This paper presents a dynamic analysis of a two-spool gas turbine helicopter engine incorporating intershaft rolling element bearings between the gas generator and power turbine rotors. The analysis includes the nonlinear effects of a squeeze film bearing incorporated on the gas generator rotor. The analysis includes critical speeds and forced response of the system and indicates that substantial dynamic loads may be imposed on the intershaft bearings and main bearing supports with an improperly designed squeeze film bearing. A comparison of theoretical and experimental gas generator rotor response is presented illustrating the nonlinear characteristics of the squeeze film bearing. It was found that large intershaft bearing forces may occur even though the engine is not operating at a resonant condition.
Ultra-Lean Combustion at High Inlet Temperatures
Authors: Anderson D. N.
Published: April 2015

Combustion at inlet-air temperatures of 1100 to 1250 K was studied for application to advanced automotive gas turbine engines. Combustion was initiated by the hot environment, and therefore no external ignition source was used. Combustion was stabilized without a flameholder. The tests were performed in a 12-cm-diameter test section at a pressure of 2.5 × 105 Pa, with reference velocities of 32 to 60 m/s and at maximum combustion temperatures of 1350 to 1850 K. Number 2 diesel fuel was injected by means of a multiple-source fuel injector. Unburned hydrocarbons emissions were negligible for all test conditions. Nitrogen oxides emissions were less than 1.9 g NO2/kg fuel for combustion temperatures below 1680 K. Carbon monoxide emissions were less than 16 g CO/kg fuel for combustion temperatures greater than 1600 K, inlet-air temperatures higher than 1150 K, and residence times greater than 4.3 ms.
Analysis for Predicting Adiabatic Wall Temperatures With Single Hole Coolant Injection Into a Low Speed Crossflow
Authors: Wang C. R. , Papell S. S. , Graham R. W.
Published: April 2015

Assuming the local adiabatic wall temperature equals the local total temperature in a low speed coolant mixing layer, integral conservation equations with and without the boundary layer effects are formulated for the mixing layer downstream of a single coolant injection hole oriented at a 30 degree angle to the crossflow. These equations are solved numerically to determine the center-line local adiabatic wall temperature and the effective coolant coverage area. Comparison of the numerical results with an existing film cooling experiment indicates that the present analysis permits a simplified but reasonably accurate prediction of the centerline effectiveness and coolant coverage area downstream of a single hole crossflow stream wise injection at 30-deg inclination angle.
Chemical and Physical Properties of Soot as a Function of Fuel Molecular Structure in a Swirl-Stabilized Combustor
Authors: Himes R. M. , Hack R. L. , Samuelsen G. S.
Published: April 2015

Soot samples were extracted from a swirl-stabilized, liquid-fuel fired laboratory combustor to (i) assess the validity of the ASTM smoke point test in predicting the sooting characteristics of fuels in complex combustion systems and (ii) assess the effect of fuel molecular structure and smoke suppressant additives on the physical and chemical properties of soot. Fuels utilized were shale JP-8, isooctane, and blends of isooctane with either decalin, toluene, tetralin, or 1-methylnapthalene such that smoke points similar to JP-8 were achieved. Each fuel was separately blended with 0.05 percent (by weight) ferrocene smoke suppressant. The results indicate that the ASTM test can be misleading, increased fuel molecular complexity increases soot content of higher molecular weight polycyclic aromatics, and ferrocene additive reduces small particle number density but not necessarily the soot mass loading.
A Computational Design Method for Transonic Turbomachinery Cascades
Authors: Sobieczky H. , Dulikravich D. S.
Published: April 2015

This paper describes a systematical computational procedure to find configuration changes necessary to modify the resulting flow past turbomachinery cascades, channels and nozzles, to be shock-free at prescribed transonic operating conditions. The method is based on a finite area transonic analysis technique and the fictitious gas approach. This design scheme has two major areas of application. First, it can be used for design of supercritical cascades, with applications mainly in compressor blade design. Second, it provides subsonic inlet shapes including sonic surfaces with suitable initial data for the design of supersonic (accelerated) exits, like nozzles and turbine cascade shapes. This fast, accurate and economical method with a proven potential for applications to three-dimensional flows is illustrated by some design examples.
Heat Transfer Experiments and Flow Visualization for Arrays of Short Pin Fins
Authors: Metzger D. E. , Haley S. W.
Published: April 2015

Results from several sets of experiments are presented to illustrate the character of streamwise heat transfer development in large aspect ratio ducts filled with uniform staggered arrays of circular pins. The short (height-to-diameter ratio 1.0) pins span the full height of the duct and are packed in moderately dense arrays (pitch-to-diameter ratios 1.32 to 2.5) typical of internal cooling applications in gas turbine airfoils. Heat transfer experiments have been performed on two separate test sections utilizing (i) highly conducting, fin effectiveness unity pins, and (ii) low conductivity, fin effectiveness near zero pins. In both cases the streamwise development of heat transfer, averaged across the duct width, is resolved to a single pin row spacing. Additional information on the flowfield and local heat transfer is provided from a large scale test rig where kerosene-lamp black flow visualization and small heat flux gages were utilized.
Design of a Power Recovery System to Provide Reboiler Heat as Well as Compression Horsepower
Authors: Baudat N. P. , Fan S. K.
Published: April 2015

In a typical LPG recovery plant, heat is needed for an amine reboiler, as well as additional horsepower to compress residue gas to pipeline pressure. With the design of a power recovery package, waste heat from turbine exhaust can be utilized to supplement the necessary horsepower and to fulfill the amine reboiler duty requirement. This reduces the number of turbines needed to achieve the compression and hence the operating cost. This paper discusses the design of such a system using propane as the power fluid, both from the application point of view as a pure heat medium system, and a power recovery system.
Flow Distributions and Discharge Coefficient Effects for Jet Array Impingement With Initial Crossflow
Authors: Florschuetz L. W. , Isoda Y.
Published: April 2015

Two-dimensional arrays of circular air jets impinging on a surface parallel to the jet orifice plate are considered. The jet flow, after impingement, is constrained to exit in a single direction along the channel formed by the jet orifice plate and the impingement surface. In addition to the crossflow which originates from the jets following impingement, an initial (independent) crossflow is present which approaches the array through an upstream extension of the channel. The configurations considered are intended to model the impingement cooled mid-chord region of gas turbine airfoils in cases where an initial crossflow is also present. Experimentally determined row-by-row streamwise distributions of the jet and crossflow velocities are presented for ratios of the initial crossflow rate to the total jet flow rate ranging from zero to unity. Comparisons are drawn between the measured flow distributions and a theoretical model which is presented. Effects of crossflow velocity and impingement surface proximity on jet hole discharge coefficients are also presented and discussed.
The Evolution of a Reliable Gas Turbine
Authors: Brandt D. E. , Walsh E. J. , Kunkel R. G.
Published: April 2015

This paper presents the evolution of a reliable and cost effective heavy duty gas turbine. Its pedigree is discussed, including the correction of deficiencies in an earlier turbine design. Specific topics addressed include the correction of field developed design deficiencies in the earlier turbine, the prototype and field validation of these earlier turbine deficiencies and the prototype and field validation of the new turbine which was scaled from the earlier design.
Modal Balancing of a Multi-Mass Flexible Rotor Without Trial Weights
Authors: Palazzolo A. B. , Gunter E. J.
Published: April 2015

In this paper, a procedure is presented to determine the unbalance distribution in a multi-mass flexible rotor system without requiring that trial weights be placed upon the shaft to first determine the influence coefficient matrix of the various balance planes. A modified Nyquist plotting procedure is presented to generate a polar plot of proximity probe measurements for determination of the 90-deg phase shift position of the modal eccentricity. By knowing the rotor modal mass and mode shape, a modal balancing distribution can be calculated. This relationship provides a quick procedure in estimating a first mode balance correction weight in both magnitude and angular location. An application is presented for a steam turbine during the startup of a hydrogen gas compression train. Higher order modal unbalance corrections are shown to be calculable in a similar manner.
NASA ECI Programs: Benefits to Pratt & Whitney Engines
Authors: Gaffin W. O.
Published: April 2015

The NASA-sponsored Engine Component Improvement (ECI) Performance Improvement Program at Pratt & Whitney advanced the state-of-the-art of thermal barrier coatings and ceramic seal systems, demonstrated the practicality of an advanced turbine clearance control system and an advanced fan design in the JT9D engine, and demonstrated the advantages of modern cooling, sealing and aerodynamic designs in the high pressure turbine and compressor of the JT8D engine. Several of these improvements are already in airline service in JT8D and JT9D engines and others will enter soon in advanced models of these engines. In addition, the technology advances are being transferred to completely new engine configurations, the PW2037 and the NASA-sponsored Energy Efficient Engine (E3).
Steam Injection in Medium-BTU Gas-Fueled, High Temperature Combined Cycle Power Plants
Authors: Lewis J. P. , Kinney C.
Published: April 2015

The potential benefits of steam injection into the combustion chamber of a medium-Btu gas-fueled, high temperature gas turbine combined cycle power plant have been investigated. The study focused on using steam injection for power augmentation during periods when the power plant was either operated on high-Btu fuel or operated on a hot day with its normal medium-Btu fuel. A steam injection ratio (steam/combustion air) of 0.06 could restore the 10.8-percent power loss incurred by the plant when operated on natural gas. A steam injection ratio of 0.08 could restore the 14.2-percent power loss incurred on a 100°F (37.8°C) day. Overall plant water consumption remains relatively unchanged during periods of steam injection because reductions in cooling tower makeup requirements tend to offset the water lost by steam injection.
Regenerated Marine Gas Turbines: Part I — Cycle Selection and Performance Estimation
Authors: Bowen T. L. , Ness J. C.
Published: April 2015

Analytical studies are currently being conducted by the David Taylor Naval Ship R&D Center to assess the suitability of regenerative-cycle and intercooled, regenerative-cycle gas turbines for naval applications. This paper, which is presented in two parts, discusses results of initial investigations to identify attractive engine concepts based on existing turbomachinery and to consider the regenerator technology required to develop these engine concepts. Part I of the paper deals with the attractive engine concepts. A survey of simple-cycle engines rated from 2500 to 50,000 hp (2 to 37 MW) was conducted to determine the cycle conditions, performance characteristics, and mechanical configurations of current marine gas turbines. Comparative cycle studies were performed to establish the performance trends of the simple, regenerative, intercooled-simple, and intercooled-regenerative cycles. Hypothetical engine concepts are described which illustrate the improved performance obtained by adding heat exchangers for regeneration and intercooling to today’s simple-cycle marine engines.
Fuel Microemulsions for Jet Engine Smoke Reduction
Authors: Naegeli D. W. , Moses C. A.
Published: April 2015

The concept of water and alcohol/fuel microemulsions for the purpose of reducing smoke emissions from jet engine test cells was studied in a T-63 gas turbine combustor. Several ethanol/fuel, methanol/fuel, and water/fuel microemulsions were prepared with JP-4 and JP-8 base fuels and the appropriate surfactants; anhydrous ethanol was miscible in both base fuels. These blends reduced radiation and exhaust smoke, increased CO and total hydrocarbon emissions, and decreased combustion efficiency. NOx was reduced when the surfactant did not contain nitrogen. The reductions in smoke and radiation correlated with changes in the H/C ratio of the fuel blends. Anhydrous ethanol/fuel solutions were most effective in reducing smoke from the standpoint of cost, operational, and systems effects.
On the Influence of the Number of Stages on the Efficiency of Axial-Flow Turbines
Authors: Lozza G. , Macchi E. , Perdichizzi A.
Published: April 2015

The selection of the number of stages of a turbine is a compromise between the two often conflicting requirements of increasing the efficiency and decreasing the machine complexity and cost. A sound prediction of the turbine efficiency variation with the number of stages is therefore useful. In the paper, a computer code capable of optimizing the more significant design variables of a multistage axial-flow turbine is described. The selection of the optimizing design variables, the assumptions made for the constraints within which the solution is searched and the optimization procedure are discussed. Losses are predicted by the Craig and Cox correlation. A computer program is used to design and predict the performance of a number of representative turbines. Similarity parameters are introduced to generalize the obtained results after a discussion of their physical significance for multistage turbine handling compressible flow. The influence on the overall turbine efficiency of the number of stages is derived as a function of expansion ratio, specific speed and turbine dimensions.
A Visual Study of Turbine Blade Pressure-Side Boundary Layers
Authors: Han Lit S. , Cox W. R.
Published: April 2015

Boundary layer characteristics on the pressure-side of a turbine airfoil were investigated experimentally in a three-blade cascade tunnel. The blades had a chord length of 21 in. to facilitate flow visualization and high-speed photography. The investigation revealed the existence of the Gortler’s vortices appearing in spurts in regions of severe curvature. In the trailing edge region, Karman vortices were detected and found to interact strongly with the Gortler’s vortices convected thereto.
F-14 Inlet Development Experience
Authors: Tindell R. H. , Hoelzer C. A. , Alexander D.
Published: April 2015

This paper reviews the F-14 inlet design and discusses the wind tunnel and flight test results of investigations that can contribute to more advanced inlet designs.
Atomization Quality of Twin Fluid Atomizers for Gas Turbines
Authors: Elkotb M. M. , Mahdy M. A. Elsayed , Montaser M. E.
Published: April 2015

A detailed investigation of the effect of nozzle/needle diameter ratio, normal fuel area, swirler degree, air pressure, fuel pressure on flow number, cone angle and droplet size distribution of external mixing twin fluid atomizers is given in this paper. Forty atomizers have been constructed to prevent mutual effect of various parameters. Flow number and cone angle are found to increase with nozzle/diameter ratio, and to decrease with the increase of air pressure. Optimum fuel flow is obtained at swirler angle 30-deg, while cone angle increases with increase of swirler angle. Sauter mean diameter decreases with the increase of air pressure and decrease of fuel pressure. Suitable functions are derived for droplet size distribution, Sauter mean diameter, and flow number. They are suitable to predict the geometry of the atomizer and to be used also in a prediction model for the calculation of fuel concentration and heat release.
Measurements of Squeeze Film Bearing Forces to Demonstrate the Effect of Fluid Inertia
Authors: Tichy John A.
Published: April 2015

Squeeze film dampers are commonly applied to high speed rotating machinery, such as aircraft engines, to reduce vibration problems. The theory of hydrodynamic lubrication has been used for the design and modeling of dampers in rotor dynamic systems despite typical modified Reynolds numbers in applications between ten and fifty. Lubrication theory is strictly valid for Reynolds numbers much less than one, which means that fluid viscous forces are much greater than inertia forces. Theoretical papers which account for fluid inertia in squeeze films have predicted large discrepancies from lubrication theory, but these results have not found wide acceptance by workers in the gas turbine industry. Recently, experimental results on the behavior of rotor dynamic systems have been reported which strongly support the existence of large fluid inertia forces. In the present paper direct measurements of damper forces are presented for the first time. Reynolds numbers up to ten are obtained at eccentricity ratios 0.2 and 0.5. Lubrication theory underpredicts the measured forces by up to a factor of two (100% error). Qualitative agreement is found with predictions of earlier improved theories which include fluid inertia forces.
Trajectories of Ash Particles Through a Coal-Burning Gas Turbine
Authors: Beacher B. , Tabakoff W.
Published: April 2015

A three-dimensional algorithm was previously developed to compute more accurate particle trajectories through turbomachinery blade rows. The capabilities of this algorithm are demonstrated in this paper with trajectory analyses through a coal-burning gas turbine developed by the Bureau of Mines. This five-stage axial turbine contains three-dimensional variations in both the geometry and the gas flow field that have a significant effect upon the trajectories of small (10 micron) coal ash particles. The trajectory analyses performed through the first three blade rows describe particle motion similar to that implied by the erosion patterns observed after testing. Particle impacts are predicted in the regions of the blade surfaces that experienced erosion. Particle impact characteristics of angle and velocity correlate qualitatively with the relative amounts of erosion observed among different regions of the blade surfaces.
AGT101 Advanced Gas Turbine Technology Update
Authors: Kidwell J. R. , Kreiner D. M. , Rackley R. A. , Mason J. L.
Published: April 2015

The Garrett/Ford Advanced Gas Turbine (AGT) Technology Project, authorized under NASA Contract DEN3-167, is sponsored by and is part of the United States Department of Energy Gas Turbine Highway Vehicle System Program. Program effort is oriented at providing the United States automotive industry the high risk long-range technology necessary to produce gas turbine powertrains for automobiles that will have reduced fuel consumption and reduced environmental impact. The AGT101 power section is a 74.6 kW (100 hp), regenerated single-shaft gas turbine engine operating at a maximum turbine inlet temperature of 1371°C (2500°F). Maximum rotor speed is 10,472 rad/sec (100,000 rpm). All high temperature components, including the turbine rotor, are ceramic. Development has progressed through aerothermodynamic testing of all components with compressor and turbine performance goals achieved. Some 200 hours of AGT101 testing has been accumulated at a nominal 871°C (1600°F) on three metal engines. Individual and collective ceramic component screening tests have been successfully accomplished at temperatures up to 1149°C (2100°F). Ceramic turbine rotors have been successfully cold spun to the required proof speed of 12,043 rad/sec (115,000 rpm), a 15-percent overspeed, and subjected to dynamic thermal shock tests simulating engine conditions. Engine testing of the ceramic structures and of the ceramic turbine rotor is planned in the near future.
Numerical Flow Analysis of Fully Three-Dimensional Turbine Cascades
Authors: Koya Masahiko , Kotake Susumu
Published: April 2015

In order to calculate higher subsonic or transonic flows in highly three-dimensionally twisted turbine blade cascades, the finite volume integral method of solving the governing equations is implemented for the treatment of boundary conditions and the discretization scheme.

The developed scheme reduces the discretization error associated with the distorted grid configuration of highly three-dimensional blades. With the developed method, flows in three typical turbine blade cascades have been calculated.

The present scheme can be applied to fully three-dimensional flow through complete turbine stages.
Mass Flow Limitation of Supersonic Blade Rows due to Leading Edge Blockage
Authors: Starken Hans , Yongxing Zhong , Schreiber Heinz-Adolf
Published: April 2015

The supersonic flow passing through the blade row of an axial flow compressor depends on the magnitude of the axial inlet Mach number. If the upstream stream tube is convergent, the axial Mach number remains subsonic and the unique incidence relation holds between inlet Mach number and inlet flow angle. This paper presents the influence of leading edge thickness and suction surface angle on the unique incidence and choking of supersonic blade rows. The theoretical results were experimentally verified in supersonic cascade wind tunnel tests.
Highly Compact Ceramic Recuperator for Engine Applications
Authors: Kleiner R. N. , Strasbaugh L. R. , Coubrough L. E.
Published: April 2015

Metallic plate-and-fin recuperators for heat engine applications are one of the most expensive components of the engine because of the high temperature alloys required and the inherent expense of brazing or welding the individual plates. A highly compact, all-prime surface, internally manifolded, plate-and-fin ceramic recuperator has been developed to deliver equivalent high performance at reduced cost. Performance and economics of this unique recuperator are presented.
The nonmagnetic nucleus of comet 67P/Churyumov-Gerasimenko
Authors: Auster Hans-Ulrich , Apathy Istvan , Berghofer Gerhard , Fornacon Karl-Heinz , Remizov Anatoli , Carr Chris , Güttler Carsten , Haerendel Gerhard , Heinisch Philip , Hercik David , Hilchenbach Martin , Kührt Ekkehard , Magnes Werner , Motschmann Uwe , Richter Ingo , Russell Christopher T. , Przyklenk Anita , Schwingenschuh Konrad , Sierks Holger , Glassmeier Karl-Heinz
Published: April 2015

Knowledge of the magnetization of planetary bodies constrains their origin and evolution, as well as the conditions in the solar nebular at that time. On the basis of magnetic field measurements during the descent and subsequent multiple touchdown of the Rosetta lander Philae on the comet 67P/Churyumov-Gerasimenko (67P), we show that no global magnetic field was detected within the limitations of analysis. The Rosetta Magnetometer and Plasma Monitor (ROMAP) suite of sensors measured an upper magnetic field magnitude of less than 2 nanotesla at the cometary surface at multiple locations, with the upper specific magnetic moment being <3.1 × 10
−5
ampere–square meters per kilogram for meter-size homogeneous magnetized boulders. The maximum dipole moment of 67P is 1.6 × 10
8
ampere–square meters. We conclude that on the meter scale, magnetic alignment in the preplanetary nebula is of minor importance.
Beyond 3D culture models of cancer
Authors: Tanner Kandice , Gottesman Michael M.
Published: April 2015

Three-dimensional culture models can represent cancer and its microenvironment and provide a platform for pharmaceutical testing.
Clinical impact of the NKp30/B7-H6 axis in high-risk neuroblastoma patients
Authors: Semeraro Michaela , Rusakiewicz Sylvie , Minard-Colin Véronique , Delahaye Nicolas F. , Enot David , Vély Frédéric , Marabelle Aurélien , Papoular Benjamin , Piperoglou Christelle , Ponzoni Mirco , Perri Patrizia , Tchirkov Andrei , Matta Jessica , Lapierre Valérie , Shekarian Tala , Valsesia-Wittmann Sandrine , Commo Frédéric , Prada Nicole , Poirier-Colame Vichnou , Bressac Brigitte , Cotteret Sophie , Brugieres Laurence , Farace Françoise , Chaput Nathalie , Kroemer Guido , Valteau-Couanet Dominique , Zitvogel Laurence
Published: April 2015

Natural killer cell activity and NKp30/B7-H6 interaction are prognostic biomarkers in high-risk neuroblastoma patients.
Shaping up nicely
Authors: Spiller Kara L.
Published: April 2015

Sophisticated imaging reveals that the shape of implanted biomaterials determines their ability to support blood vessel growth.
Beating BRAF resistance
Authors: Behjati Sam
Published: April 2015

A sequencing study defines resistance mechanisms to BRAF inhibition in colorectal tumors and reveals a possible Achilles’ heel.
Of obese mice and monkeys: Protective effects of PI3K inhibition
Authors: Alvarez Jessica A.
Published: April 2015

Inhibiting PI3K signaling in obese mice and rhesus monkeys safely reduced adiposity and metabolic abnormalities.