bluuebunny/crossref_metadata_2025 huggingface dataset:
Putting on the Brakes or Pressing on the Gas? Media Attention and the Speed of Policymaking
Authors: Wolfe Michelle
Published: January 2012

Media attention is fundamental to the policy process and policy change in punctuated equilibrium theory. In this literature, media attention is usually conceptualized as fomenting or contributing to shifts in attention, positive feedback, and large‐scale policy change. This article extends how we understand the role of the media and punctuated equilibrium by arguing that media coverage can also contribute to negative feedback and stability in the political system. Media attention should also slow down the speed of policymaking and the momentum for policy change as new policy participants and problem definitions enter the debate. Using event history analysis, this article tests the effects of media coverage on the length of time it takes legislation, once introduced, to become law for public laws from the 109th U.S. Congress (2005–06). Findings provide support for media attention “putting the brakes” on policymaking. Controlling for other factors, the speed of bill passage slows down as media attention increases. This effect decays over time for high levels of media coverage.
Training volume and body composition as risk factors for developing jumper's knee among young elite volleyball players
Authors: Visnes H. , Bahr R.
Published: January 2012

Training volume and body composition have been suggested as risk factors for jumper's knee among athletic youth, but research is lacking. The aim of this 4‐year prospective cohort study was to examine the relationship between training and competition load, body composition, and risk for developing jumper's knee. Participants are elite volleyball players, aged 16–18 years. Training and competition load was recorded continuously and body composition semiannually. Jumper's knee was diagnosed on a standardized clinical examination. We recruited 141 healthy students (69 males and 72 females), and 28 developed jumper's knee (22 boys and six girls). In a multivariate analyses, boys had three to four times higher risk compared with girls. Volleyball training had an odds ratio (OR) 1.72 (1.18–2.53) for every extra hour trained, and match exposure was the strongest sports‐related predictor for developing jumper's knee with an OR of 3.88 (1.80–8.40) for every extra set played per week. We did not detect any significant differences between the groups in body composition at the time of inclusion or in the change of body composition during the study period. Conclusion, male gender, a high volume of volleyball training and match exposure were risk factors for developing jumper's knee.
The function of platelet‐derived growth factor in the differentiation of mouse tongue striated muscle
Authors: Suzuki E. , Aoyama K. , Fukui T. , Nakamura Y. , Yamane A.
Published: January 2012

Suzuki E., Aoyama K., Fukui T., Nakamura Y., Yamane A. The function of platelet‐derived growth factor in the differentiation of mouse tongue striated muscle.  Orthod Craniofac Res 2012;15:39–51. © John Wiley & Sons A/S

Structured Abstract

Objective –  to determine the function of platelet‐derived growth factor (PDGF) in the final differentiation phase of tongue striated muscle cells.

Materials and Methods –  We analyzed the expressions of PDGF‐A, ‐B, platelet‐derived growth factor receptor (PDGFR)‐α, and PDGFR‐β in mouse tongues between embryonic days (E) 11 and 15. Furthermore, we examined the effects of human recombinant PDGF‐AB and the peptide antagonist for PDGFRs using an organ culture system of mouse embryonic tongue. Mouse tongues at E12 were cultured in BGJb medium containing human recombinant PDGF‐AB for 4 days or the peptide antagonist for PDGF receptors for 8 days.

Results –  PDGF‐A, ‐B, PDGFR‐α, and ‐β were expressed in the differentiating muscle cells between E11 and 15. The human recombinant PDGF‐AB induced increases in the mRNA expressions of myogenin and muscle creatine kinase (MCK) and the number of fast myosin heavy chain (fMHC)‐positive cells, markers for the differentiation of muscle cells. On the other hand, the peptide antagonist for PDGFRs induced suppressions in the mRNA expressions of myogenin and MCK, and the number of fMHC‐positive cells. Both the PDGF‐AB and the antagonist failed to affect the expressions of cell proliferation markers.

Conclusion –  These results suggest that PDGF functions as a positive regulator in the final differentiation phase of tongue muscle cells in mouse embryos.
Orthodontic tooth movement causes decreased promoter expression of collagen type 1, bone sialoprotein and alpha‐smooth muscle actin in the periodontal ligament
Authors: Olson C. , Uribe F. , Kalajzic Z. , Utreja A. , Nanda R. , Rowe D. , Wadhwa S.
Published: January 2012

Olson C., Uribe F., Kalajzic Z., Utreja A., Nanda R., Rowe D., Wadhwa S.  Orthodontic tooth movement causes decreased promoter expression of collagen type 1, bone sialoprotein and alpha‐smooth muscle actin in the periodontal ligament.  Orthod Craniofac Res 2012;15:52–61 © John Wiley & Sons A/S

Structured Abstract

Objective –  To evaluate the effects of orthodontic tooth movement on the promoter expression of collagen type 1 (3.6Col1), bone sialoprotein (BSP) and alpha‐smooth muscle actin (αSMA) in the periodontal ligament (PDL) using transgenic mice containing transgenes of these promoters fused to green fluorescent proteins (GFP).

Materials and Methods –  The maxillary first molars of 10‐12 week‐old transgenic mice were loaded with 10–12 g of force for 12, 48 h, or 7 days. Mice were transgenic for one of the following GFP‐tagged bone markers of osteoblast lineage cells: 3.6‐kb fragment of the rat collagen type 1 promoter (3.6Col1), BSP or α‐smooth muscle actin (αSMA). Loaded molars under compression and tension were compared with contra‐lateral unloaded controls.

Results –  On the compression side of the PDL, orthodontic tooth movement caused a significant decrease in GFP expression of all the promoters at each time point. On the tension side, there was a significant increase in BSP–GFP expression, 12 h following loading compared to the contralateral unloaded controls.

Conclusions –  An in vivo tooth movement model using transgenic mice with promoter–GFP constructs provides an efficient and effective way of investigating the cellular events underlying orthodontic tooth movement. PDL cells may undergo decreased differentiation in response to the compressive force.
Treatment of lepromatous ulcers using citric acid as a sole antimicrobial agent
Authors: Nagoba Basavraj S , Wadher Bharat J , Rao Arunkumar , Selkar Sohan P , Gandhi Rajan C
Published: January 2012

A prospective study was carried out to assess the role of citric acid as a sole antimicrobial agent in the management of lepromatous ulcers. Thirty‐four known cases of lepromatous ulcers not responding to conventional antibiotic therapies for long duration were investigated for culture and susceptibility studies. Staphylococcus aureus (25·00%) and Klebsiella spp. (23·43%) were found to be the most common isolates. Amikacin (68·75%) and ciprofloxacin (67·18%) were found to be the most effective antimicrobial agents. Topical application of citric acid ointment resulted in complete healing in 25 (73·52%) cases. In eight cases (26·48%), there was elimination of infective agent from ulcer site and formation of healthy granulation, but no complete healing of ulcer was seen. Results indicate that citric acid is the best alternative for the effective management of lepromatous ulcers when other therapies are exhausted.
Assessing the Impact of Thrombolysis on Progress through Inpatient Rehabilitation after Stroke: A Multivariable Approach
Authors: Meyer M. , Murie-Fernandez M. , Hall R. , Liu Y. , Fang J. , Salter K. , Foley N. , Teasell R.
Published: January 2012

Background

Acute administration of tissue plasminogen activator has been shown to improve immediate and long-term patient recovery after ischaemic stroke. Yet, despite widespread clinical application, many patients who receive acute tissue plasminogen activator still require inpatient rehabilitation.

Aims and Hypothesis

This study aimed to examine the effect of tissue plasminogen activator administration on recovery among patients requiring inpatient rehabilitation after stroke in Ontario, Canada. It was hypothesized that after covariate adjustment, administration of tissue plasminogen activator would be associated with accelerated progress through inpatient rehabilitation.

Methods

Acute and rehabilitation data were retrieved from the Registry of the Canadian Stroke Network and the National Rehabilitation Reporting System for all ischaemic stroke patients admitted to an acute facility and a rehabilitation unit between July 1, 2003 and March 31,2008. Patients were divided into two groups: those who received tissue plasminogen activator and those who were medically eligible but did not receive tissue plasminogen activator. Three rehabilitation progress indicators were compared between groups: Functional Independence Measure gain, active length of stay, and discharge destination. Indicators were modelled using multivariable generalized linear models or logistic regression as appropriate.

Results

Patients who received tissue plasminogen activator experienced shorter active lengths of stay (log estimate ± standard error: −0.04 ± 0.01 days), and were slightly more likely to be discharged home compared to controls (adjusted odds ratio 1.35, 95% confidence interval 1.004–1.82). No differences were noted on Functional Independence Measure gain during rehabilitation.

Conclusion

Results suggest that tissue plasminogen activator may contribute to accelerated progress through inpatient rehabilitation; however, there is no evidence to suggest that it contributes to greater functional improvement as measured by the Functional Independence Measure.
Effect of Sexual Maturation on Thermal Stability, Viscoelastic Properties, and Texture of Female Rainbow Trout, Oncorhynchus mykiss, Fillets
Authors: Aussanasuwannakul Aunchalee , Weber Greg M. , Salem Mohamed , Yao Jianbo , Slider Susan , Manor Meghan L. , Brett Kenney P.
Published: January 2012

Abstract:  The nutrient and energy demand of sexual maturation in many fish cultivars causes structural change to key contractile proteins and thereby, affects fillet firmness. Thermal denaturation and viscoelastic properties of white muscle from diploid (2N; fertile) and triploid (3N; sterile) female rainbow trout were investigated at 6 age endpoints from July 2008 through spawning in March 2009. Differential scanning calorimetry showed, in March, that the actin denaturation temperature (Tmax,actin) of 2N females was higher than that observed in 3N females (78.17 versus 77.27 °C). From 35 to 45 °C, viscoelastic measurement revealed that muscle from 2N females and younger fish (July, 16 mo) had greater elasticity (lower tan δ) than muscle from 3N females and older fish (November to March; 20 to 24 mo), respectively. The highest elastic response and the firmest fillets were observed in July. Raw fillets were softer (Allo‐Kramer shear; P < 0.05) from September to January (288.77 g/g on average) than those collected in July (475.15 g/g) and March (366.79 g/g). Soft fillets became firmer after cooking except for January samples. Greater cook yield and softer fillets were observed in January compared to December. Lipid accumulation in 3N females may lubricate muscle fibers and protect them from losing functionality during the spawning season for animals on a high plane of nutrition.

Practical Application:  The relationship between fish maturation, measured as egg development, and chemical characteristics of fillets from fertile and sterile fish was evaluated. Thermal denaturation and viscoelastic characterization revealed changes in stability and gelling properties of muscle proteins that were related to changes in fillet texture.
Total Phenols and Antioxidant Capacity in 10 Moroccan Pomegranate Varieties
Authors: Legua Pilar , Melgarejo Pablo , Abdelmajid Haddioui , Martínez Juan José , Martínez Rafael , Ilham Hmid , Hafida Hanine , Hernández Francisca
Published: January 2012

Abstract:  The study focused on characterizing the 10 major Moroccan cultivars to acknowledge the quality and bioactive compounds of the fruits. The following determinations were assessed: pomegranate fruit maturity index, which truly defines juice taste, as well as organic acids and sugar contents, total phenols, and antioxidant activity of pomegranate juice. The cultivar per se (genotype) behaved as the most influencing factor conditioning pomegranate sugar and organic acids profiles, antioxidant activity, and total phenolics. The assessment of pomegranate chemical compositions implies the great potential of Moroccan cultivars for both fresh market and fruit processing. In fact, the "Hamde” sour cv. seems particularly suitable for juice production because of its high phenolics content. Additionally, the presence of bioactive compounds in pomegranate juices may encourage their consumption for potential health benefits.

Practical Application:  The cultivar per se (genotype) behaved as the most influencing factor conditioning pomegranate sugar and organic acids profiles, antioxidant activity, and total phenolics. Given the divergence observed on bioactive compounds concentrations and antioxidant activity among evaluated cultivars, the genotype factor should be considered as the most influencing factor in future breeding programs to enhance the synthesis of beneficial bioactive compounds.
Characterization of Ergocalciferol Loaded Solid Lipid Nanoparticles
Authors: Patel Mandar R. , San Martin‐Gonzalez M. Fernanda
Published: January 2012

Abstract:  The use of solid lipid nanoparticles (SLNs) is a technique that has been widely used in the pharmaceutical industry for the last 2 decades and has become of increasing interest to food scientists due to its potential for encapsulation and controlled release. Ergocalciferol (vitamin D2) is a bioactive compound whose deficiency may lead to rickets in children and osteomalacia in adults. In this study, ergocalciferol was encapsulated in tripalmitin SLNs stabilized by polysorbate 20 (Tween 20). SLN dispersions (5% w/w) were prepared by hot homogenization technique using a nozzle‐type high‐pressure homogenizer. Ergocalciferol at 0%, 5%, 10%, 15%, and 20% (w/w of lipid) was dissolved in the molten lipid at 80 °C, mixed with a 5% (w/w) aqueous solution of polysorbate 20 and homogenized at 138 MPa at 80 °C. Particle size, thermal properties, and microstructure were evaluated by dynamic light scattering (DLS), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM) respectively. As the proportion of ergocalciferol in the SLN increased from 0% to 20%, the Z‐average values of the particles gradually decreased (P≤ 0.05) from approximately 120 nm to approximately 65 nm. DSC analysis of freeze dried SLN samples showed gradual decrease in enthalpies of fusion and crystallization for stable β‐subcell whereas for SLN dispersions, the enthalpy of fusion of unstable α‐subcell crystal increased with increased ergocalciferol loading. The TEM images of the ergocalciferol loaded SLN samples showed the presence of spherical as well as rod‐shaped nanoparticles. It was also observed that the turbidity of the SLN dispersions reduced noticeably with increased ergocalciferol loading. This finding could be useful in terms of fortification of clear juices with ergocalciferol.

Practical Application:  Solid lipid nanoparticles (SLNs) were used in this study to encapsulate vitamin D2, a vitamin important for bone health. It was found that as the concentration of vitamin D2 increased in the lipid phase of SLN dispersion, the clarity of the dispersion increased. Also, with increased vitamin D2 concentration, the stability of lipid crystal structure was affected in a way that indicates higher capacity of lipid to incorporate the vitamin molecules and hence to protect them better from oxygen and light. This vitamin loaded SLNs may offer alternatives to milk and margarine as a source of vitamin D.
DEFENSIVE PROCESSES AND DECEPTION: AN ANALYSIS OF THE RESPONSE OF THE INSTITUTIONAL CHURCH TO DISCLOSURES OF CHILD SEXUAL ABUSE
Authors: Gardner Fiona
Published: January 2012

abstract

Disclosures about the extent of sexual abuse within the church context and the gradual revealing of the way that the institution has responded in the past indicate underlying anxiety and associated defensive processes. It is suggested in this paper that these processes have led to secrecy and deception. Similarities between the behaviour of perpetrators and the response by the church are explored alongside current preoccupations within the church. Psychoanalytic ideas and theories of organizational dynamics are used to explore and reflect on the fantasies and explicit and implicit assumptions within the institution. It is suggested that the church has displayed institutional narcissism in its response to disclosures. Ideas are illustrated by generic situations.
The decline of moths in Great Britain: a review of possible causes
Authors: FOX RICHARD
Published: January 2012

Abstract.  1. Population declines among insects are inadequately quantified, yet of vital importance to national and global biodiversity assessments and have significant implications for ecosystem services.

2. Substantial declines in abundance and distribution have been reported recently within a species‐rich insect taxon, macro‐moths, in Great Britain and other European countries. These declines are of concern because moths are important primary consumers and prey items for a wide range of other taxa, as well as contributing to ecosystem services such as pollination.

3. I summarise these declines and review potential drivers of change. Direct evidence for causes of moth declines is extremely limited, but correlative studies and extrapolation from closely related taxa suggest that habitat degradation (particularly because of agricultural intensification and changing silviculture) and climate change are likely to be major drivers. There is currently little evidence of negative population‐level effects on moths caused by chemical or light pollution, non‐native species or direct exploitation.

4. I make suggestions for future research with a focus on quantifying impacts of land management practices, light pollution and climate change on moth population dynamics and developing evidence‐based measures that can be incorporated into agri‐environment schemes and other policy initiatives to help reverse the widespread decline of moths in Great Britain and beyond.
Death and people with learning disabilities: Interventions to support clients and carers
Authors: Cathcart Fiona
Published: January 2012

The needs of people with learning disabilities who ate bereaved have been acknowledged in the last decade. There is more understanding of ways to meet these needs. Carers need training and support when working with people who are dying or bereaved. This paper reviews the relevant literature, offers guidelines for practice and highlights areas for further development.
Stability in the structure of health locus of control among adolescents
Authors: Stanton Warren R. , Raja Shyamala Nada , Langley John
Published: January 2012

The Multidimensional Health Locus of Control (MHLC) scales have been widely used as a measure of health beliefs in adult populations. In a longitudinal study of an adolescent cohort, we examined some of the properties of the MHLC; whether there are changes in the locus of beliefs between the ages of 13 and 15 years; and the extent of gender differences at the two ages. The results provided some degree of support for the previously proposed structure of the MHLC, but showed correlations among the subscales that were higher than might be expected, and lower alpha reliability coefficients than have been reported for adult samples. There was also evidence of downward changes in scores for the 'chance' and 'powerful others' scales, as well as differences in the factor structures of females and males at age 15 years. In contrast to the structure of health beliefs found with some adult samples, 'chance' is a prominent, independent dimension of beliefs about control of health among adolescents. The independence of the 'internal control' and 'powerful others' scales seem to be a function of both age and gender. As health behaviours are multidetermined, it is concluded that the MHLC measure would be useful as part of an index of health status.
The effectiveness of a motion sickness counselling programme
Authors: Dobie Thomas G. , May James G.
Published: January 2012

Unselected volunteers were offered a course of instruction in using the cognitive‐behavioural approach to helping individuals tolerate the deleterious effects of different motion environments. In order to evaluate that programme, 11 of the participants volunteered to counsel independently individuals who were prone to motion sickness, using cognitive‐behavioural training which included reinforcement by visually induced apparent motion. The subjects were pre‐ and post‐tested by an independent observer using tolerance and motion response as the dependent variables. These test scores were compared to previous data obtained with subjects who had received counselling from an experienced counsellor, or had received no such counselling. The results indicated that the newly trained counsellors' subjects showed significant pre‐ to post‐test tolerance to the motion stimulus, although they did not benefit as much as subjects trained by the experienced counsellor. However, in terms of post‐test symptomatology and magnitude estimates of motion sickness, the trainees' subjects exhibited as much benefit as did those of the experienced counsellor. These data are taken as strong support for the feasibility of training counsellors to employ this method of alleviating motion sickness.
Symptom changes across the menstrual cycle in competitive sportswomen, exercisers and sedentary women
Authors: Choi Precilla Y. L. , Salmon Peter
Published: January 2012

Anecdotal accounts and unsystematic reports have suggested that women who exercise experience fewer premenstrual symptoms and less severe dysmenorrhoea than women who are sedentary. The present study tested this belief. Mood states and physical symptoms of 143 women were monitored for five days in each of the three phases of the cycle (mid‐cycle, premenstrual and menstrual). The women were 35 competitive sportswomen, two groups of exercisers (33 high exercisers and 36 low exercisers) and 39 sedentary women. Principal component analysis of their responses to a mood and physical symptom checklist revealed five dimensions: positive affect, negative affect, physical symptoms, fatigue and irritability. Component‐based subscale scores were calculated for all dimensions. In general, mood and symptoms were worse menstrually and premenstrually than mid‐cycle. The high exercisers experienced the greatest positive affect and sedentary women the least. The high exercisers also reported the least negative affect. The differences between exercise groups were greatest during the premenstrual and menstrual phases. These results are consistent with the belief that women who frequently exercise may be to some extent protected from deterioration of mood before and during menstruation. This, however, is not the case for competitive sportswomen.
CAMCOG—A concise neuropsychological test to assist dementia diagnosis: Socio‐demographic determinants in an elderly population sample
Authors: Huppert Felicia A. , Brayne Carol , Gill Caroline , Paykel E. S. , Beardsall Lynn
Published: January 2012

The CAMCOG, which forms part of the CAMDEX interview (Roth et al., 1986, 1988), is a brief neuropsychological battery designed to assess the range of cognitive functions required for a diagnosis of dementia, and to detect mild degrees of cognitive impairment. It was administered to a population sample of 418 elderly people (aged 77 and above) in their place of residence. The data show that in contrast to the Mini‐Mental State Examination, total CAMCOG scores are well distributed and there is no ceiling effect.

Examination of the association between CAMCOG scores and socio‐demographic variables (age, sex, education and social class) shows that each exerts a significant, and independent, effect upon performance.

CAMCOG also includes a number of subscales which assess individual areas of cognitive function. Of the eight major subscales (orientation, language, memory, attention, praxis, calculation, abstract thinking, perception), age was significantly related to all but attention; sex with attention, praxis, calculation and perception; education with language and abstract thinking; and social class with language and perception. In all these analyses, the results were adjusted for the effects of the other socio‐demographic variables using analysis of variance. However, education and social class are highly correlated variables and when the association with education is examined without adjusting for social class, attention and praxis are also found to be significantly related to education. Caution must therefore be taken when using the CAMCOG (or any other cognitive test) as a screening test for dementia, using a single, predetermined cutpoint.

In general, the combination of brevity and breadth of the CAMCOG, along with its distributional properties, makes it an attractive neuropsychological test for use in the community or the clinic.
Decentralized Peak-Shaving—Its Economic Significance to Electric Utilities
Authors: Bary Constantine W.
Published: January 2012

This paper discusses the procedure used in determining the possible economies to be obtained on an electric utility system through the establishment of an expansion policy for power production facilities wherein a certain amount of decentralized peak-shaving capacity is periodically installed. Many factors are considered in determining the amount of peak-shaving capacity and the possible effect of changes in future conditions. A simplified equation of cost savings under a stated peak-shaving policy is presented. Also included is a theoretical analysis which indicates the portion of savings attributable to the peak-shaving function as contrasted with that attributable to reduction in average reserve margins possible with the use of the smaller sized units under a decentralized peak-shaving policy.
Design and Development of a Convective Air-Cooled Turbine and Test Facility
Authors: Weatherwax W. F.
Published: January 2012

Demands for higher jet engine thrust-to-weight ratios to satisfy the needs for high Mach number and vertical take-off aircraft are continually increasing. Since World War II, the three-fold increase in thrust-to-weight ratio can be attributed almost entirely to the development of lightweight construction and the axial-flow compressor, and little credit can be given to the meager 200-F increase in turbine-inlet temperature. Increasing turbine-inlet temperature, beyond present-day material limits of 1600-1700 F, by convective air cooling, will increase the jet-engine thrust-to-weight ratio and will markedly improve the performance of the turboprop and bypass engines. The partial results of a program undertaken by the author’s company to develop a fully cooled, flight-type, turbine and test facility are reported. The design heat-transfer considerations are discussed, the test facility described, and performance results to date are given.
Some Investigations Into Transonic Axial-Flow Compressors With High Stage Load Coefficients and Low Degrees of Reaction
Authors: Wichert Karl E.
Published: January 2012

A design for a transonic axial-flow compressor is described, in which a rotor wheel with a low degree of reaction operates in subsonic flow and the stator operates in supersonic flow. A compressor was run as a single-stage compressor and an outlet pressure ratio equal to that of an orthodox compressor with 4 stages. Some discussion of another compressor in which both the rotor wheel and the stator operate in supersonic flow is also given.
Performance of Stainless-Steel Condenser Tubes
Authors: Pell Robert H.
Published: January 2012

A report of the evaluation and decision to replace copper-alloy condenser tubes with Type 304 stainless steel, and the performance during the two years since installation.
Inlet Guide Vane Performance of Centrifugal Blowers
Authors: Stepanoff A. J.
Published: January 2012

The function and effectiveness of the inlet guide vanes to control the blower output and power requirements are examined. Calculated and experimental results of the power reduction by means of guide vanes are presented. The concept of the “Inlet Specific Speed” widely used in centrifugal pump field is discussed in application to the blowers. A method of estimating the performance of single-stage blowers for any position of the guide vanes is suggested. A “casing characteristic” is introduced for this purpose and its utility for the calculation of the impeller diameter for a reduction of the output is demonstrated. The performance of the inlet vanes of multistage blowers is reviewed.
Economy of Efficient Air Preheating With Extraction Steam
Authors: Drewry M. K.
Published: January 2012

Two per cent heat rate improvement of a 275,000 kw unit results from efficient 2-stage steam air preheaters heating to 190 F with 5 F terminal temperature differences. Condenser heat rejection and turbine leaving losses are reduced substantially. Flue-gas losses are not increased. Air heater cleanliness is improved. Maintenance is reduced. Annual coal savings after fixed charges are one half of the net added investment.
Electrochemical Cylinder Corrosion
Authors: Van Der Horst J. M. A. , Schultze W. A.
Published: January 2012

The price differential between distillate and residual fuels tends to increase rather than decrease, offering a growing incentive to the use of residuals in diesel engines. In general, no specifications can be put upon residuals without largely eliminating the price advantage. Therefore special measures must be taken to assure trouble-free operation on residual fuels. Significant strides have been made in this direction, especially with regard to lubricants. New developments in protective lubrication, engine tests, and service results are discussed.
Evolution and Development of a 900-hp Marine Diesel Featuring Ruggedness and Serviceability in a 4 1/2 lb/hp Package
Authors: Wechsler L. , Thompson L. , Tsakiris E.
Published: January 2012

The paper describes the design evolution and basic features of a new 900-hp lightweight, heavy duty diesel engine. Discussions are presented which show how early field experience in lightweight diesel engines guided special engineering studies, which eventually established important features of the new engine. The paper includes technical data regarding certain design parameters important in lightweight engine construction plus performance data of the 900-hp engine. Photographs are included which show the new engine and many of its major components.
An Analysis of the Otto Cycle Taking Into Consideration the Effect of Varying Operating Parameters
Authors: Bonamy S. E.
Published: January 2012

An analysis of internal combustion engine cycles using thermodynamic charts usually involves a lengthy trial-and-error process. A graphical analysis of the results of many cycles, however, enables equations to be developed for theoretical mean effective pressure and efficiency of the Otto cycle in terms of intake and exhaust pressures, fuel-air ratio, compression ratio, and fresh charge temperature. These equations enable quick solution of a particular cycle and the effects of operating parameters on engine performance to be studied. Experimental results show similar relationships between engine performance and operating parameters to those obtained theoretically.
Influence of Geometrical Design Factors on the Bending Fatigue Strength of Crankshafts
Authors: Kano Cyrus
Published: January 2012

Bending fatigue strength data from many tests on internal combustion engine crankshafts are analyzed. This analysis results in the development of simply related strength and geometrical parameters which summarize and unify the results. The data presented are for crankshafts of one material type but in a wide range of sizes and shapes.
Investigation of a Shear-Force Pump
Authors: Hasinger S. H. , Kehrt L. G.
Published: January 2012

A radial-flow type shear-force pump is analytically and experimentally investigated and certain conclusions for the application of shear-force pumps in general are drawn.
Performance of Photovoltaic Cells at High Radiation Levels
Authors: Schoffer P. , Pfeiffer C.
Published: January 2012

The performance of p-n gridded, water-cooled silicon photovoltaic cells was measured at radiation levels of up to 250 Langley per min. Outputs exceeded 1/4 watt per sq cm. An analysis of cell operation at high fluxes permits computation of the performance over a wide range of radiation intensities from a single high-radiation voltage-current curve. An array of eight p-n cells and an optical system used with the array is described. Characteristics of n-p cells were measured, and their peculiar V-I curves are noted. Methods of improving cell performance at high fluxes are discussed.
Sulfur Chemistry and Its Role in Corrosion and Deposits
Authors: Levy Arthur , Merryman E. L.
Published: January 2012

Sulfur in fuel oil and coal, and its resultant oxidation to SO3 during combustion, is a recognized factor in corrosion and deposits. As a step toward controlling the formation of SO3, and eventually controlling the conditions and rate of corrosion, a program has been undertaken under ASME support to establish, among other things, the mechanism by which sulfur compounds are oxidized to SO2 and to SO3 in flames. The present paper reviews some of the basic thermodynamics and reaction kinetics pertaining to the oxidation of H2S and SO2, and to the SO2–SO3 equilibrium. Included in the review are discussions of the stability of H2S, the slow oxidation of sulfur vapor and of H2S, the induction period (preignition) reactions leading to the fast, explosive oxidation of H2S, and effects of additives on the explosion reaction. The heterogeneous (catalyzed) oxidation of SO2 is discussed in terms of the effects of specific catalysts on the SO2–SO3 equilibrium.
Stresses in a Hydraulic Turbine Stay Ring
Authors: Parmakian John , Ruud Frederick O.
Published: January 2012

This paper describes a method of analysis of the stresses in a hydraulic turbine stay ring which includes the effect of the bending moment applied to the stay vanes by the forces on the ring due to the membrane load of the spiral case, the pressure on the face of the ring, and the head cover load. In most cases the bending stresses in the stay vanes, previously neglected, are shown to be of substantial magnitude. These bending stresses can be reduced by proper positioning of the stay vanes within the stay ring structure.
High-Speed Rotor Suspension Formed by Fully Floating Hydrodynamic Radial and Thrust Bearings
Authors: Dworski Juraj
Published: January 2012

The hydrodynamic suspension of a 44,000-rpm gas turbine rotor is described with emphasis on interaction between the flexible rotor and its supports. Bearings with relatively large clearances are shown to allow continuous operation at the rotor first critical-speed of 22,000 rpm. The apparent absence of hydrodynamic system instabilities is attributed to the use of simple floating-sleeve bearings. A parametric study of the influence of bearing clearances upon vibrational excitation relief is presented together with test data collected on actual system hardware.
Pressure Fluctuations and Fatigue Stresses in Storage Pumps and Pump-Turbines
Authors: Strub R. A.
Published: January 2012

Similarity is shown between a model and a full scale pump or pump-turbine in the static and dynamic fields of stress and in the vibration characteristics, if the peripheral speed of rotation and the material used for the blades are the same for the two machines. Simple formulas are derived for predicting phase coincidence of the pressure fluctuations caused by the blade passage of the runner rotating in a diffuser. Test results are shown which confirm the established theory. This work was made as part of a joint development work on pump-turbine by Sulzer Brothers, Ltd., and English Electric Company.
Design of 1000-MW Steam Turbine-Generator Unit for Ravenswood No 3
Authors: Driscoll J. M. , Wilson C. D. , Rosenberg L. T.
Published: January 2012

Consolidated Edison’s 1000-mw steam turbine-generator unit for Ravenswood No. 3 will operate on a 2400-psig, 1000/1000 F steam cycle. Arrangement is close-coupled 3600/1800-rpm, cross compound, with all five turbines double flow. Both generators are of fully supercharged, hydrogen-cooled design. At each end of the 3600-rpm shaft are direct-driven half-size boiler-feed pumps while the big units two gear-driven exciters are in tandem at the generator end of the 1800-rpm shaft. The three double-flow, low-pressure turbines use 40-in. exhaust spindle blades. This world-record unit incorporates design features to assure fast starting and loading, high reliability, and efficient performance.
A Study on Reynolds Number Effects in Turbomachines
Authors: Balje´ O. E.
Published: January 2012

Typical space power units have a tendency to encounter low Reynolds numbers in the last turbine stages. Comprehensive test data on the effect of low Reynolds numbers on the efficiency of turbomachines are lacking. An attempt is made to assess this influence, using conventional aerodynamic arguments. By distinguishing between viscous and nonviscous losses some tentative values have been calculated which are in fair agreement with the few available test data. These considerations indicate that the stage pressure ratio and the specific speed affect the Reynolds number influence significantly.
Assessment of Steels for Nuclear Reactor Pressure Vessels
Authors: Cowan A. , Nichols R. W.
Published: January 2012

Some of the materials problems associated with the use of mild steels in large gas-cooled reactor pressure vessels are discussed. Tests to failure of 5-ft-dia 0.36 percent carbon-steel vessels with through-thickness longitudinal slots, supported by tests on 7-ft-wide centrally slotted flat plates, have indicated that rapid failure at working-stress levels can only initiate from very long cracks, feet rather than inches in length. Of the mechanisms whereby realistic defects can grow to these sizes, brittle-crack propagation is considered the most important and this can be prevented by the maintenance of a minimum pressurization temperature, based on the crack-arrest temperature. The tests used to assess the crack arrest temperature of plates up to 4 in. thick are described; compared with tests on thinner specimens the thick plate gives arrest temperatures higher by approximately 10 deg C per in. of test-specimen thickness. A comparison is made of crack-arrest temperature and data given by small-scale tests, particularly the Charpy V-notch test. Mechanical limitations of creep deformation in some current designs have been more restrictive on design stress than the values allowed by the existing BS.1500. The test data quoted for stress-rupture and fatigue indicate that these modes of crack extension are not important in current designs. Possible magnitudes and effects of stress concentrations are quoted but, other than a large body of satisfactory service operation, there is little direct evidence of the effect of operating in the creep range on these stress concentrations. The importance of work of this type in justifying higher design stresses and more economic use of material is emphasized.
Material Requirements for Long-Life Pressure Vessels
Authors: Langer B. F. , Harding W. L.
Published: January 2012

In this paper the authors consider the various possible modes of failure of a pressure vessel intended for long service and show which material properties are of significance in preventing them. The failure modes discussed are (a) plastic deformation and bursting; (b) brittle fracture; (c) fatigue failure; (d) creep deformation and creep rupture; (e) corrosion. The need for additional information in several areas is also noted.
Sixth International Conference on the Properties of Steam—Release
Authors: Haywood R. W.
Published: January 2012

The values of the important engineering thermodynamic properties of steam which have been generally accepted since 1934 did not cover the higher pressures and temperatures used in modern power plants because data for these conditions were not available at that time. In 1954 an international conference was convened which decided that tables covering pressures and temperatures to approximately 15000 psi and 1500 °F should be worked out for international adoption. It was also decided to include in the tables values of two transport properties (viscosity and thermal conductivity). To implement these decisions, a working committee made up of representatives of UK, BRD, USSR, and USA were appointed; at a meeting of the conference held in New York in October, 1963, this committee presented tables of proposed values of the properties based on the latest experimental work available. This Conference adopted skeleton tables of the values of (a) Thermodynamic Properties of Saturated Water and Saturated Steam; (b) Specific Volume of Compressed Water and Superheated Steam; and (c) Specific Enthalpy of Compressed Water and Superheated Steam. The values in the skeleton tables cover pressure and temperature ranges of from 0 to 1000 bars (14,500 psi) and from 0 to 800 °C (1470 °F). These tables are true skeleton tables with wide spacing between pressure and temperature values and are intended only as the basis of working tables and are attached to the Release. It was not possible for the Conference to reach final agreement on the values of the transport properties and the tables of these values are to be determined by a working group meeting in the Summer of 1964. A second working group was appointed to determine satisfactory formulas for use in interpolating between the skeleton table values of the thermodynamic properties. This group is to report at the earliest practical date, and when its work is completed new working steam tables of thermodynamic and transport properties can be prepared.
Development and Application of Nomographs for an Analysis of Compression-Ignition Engines
Authors: Van Der Werf P. , Bonamy S. E.
Published: January 2012

From an analysis of a large number of limited-pressure cycles using thermodynamic charts, nomographs are prepared. These may be used to supersede the lengthy trial-and-error process involved in cycle analysis by the charts and enable an accurate computation of engine performance and properties at salient points in the cycle to be made. Graphs prepared from the nomographs show similar trends to those obtained from tests on a single cylinder four-stroke compression-ignition engine.
Fuel-Ash Corrosion and Its Effect on Boiler Design
Authors: Hansen W. A. , Kessler G. W.
Published: January 2012

Problems inherent in boiler design owing to the phenomenon of high-temperature oil and coal-ash corrosion are reviewed. Experience and research are discussed, together with the design philosophies and procedures used by the authors’ company in the design of boiler units to alleviate, or minimize, the possibility of high-temperature corrosion. Practical corrective measures to protect boiler units encountering corrosion are noted, and laboratory and field investigations now underway to learn more about the fundamental mechanism of corrosion are described briefly.
A Review of Recent Air Force Research on Selective Solar Absorbers
Authors: Long R. L.
Published: January 2012

This paper presents a review of recent Air Force research efforts to develop new and improved solar absorber coatings for solar power generation. The work of several laboratories is described as it relates to a particular experimental approach or technique for producing selectively absorbing surfaces. Such unique techniques as microporous surfaces and metallo-organic solution decomposition are discussed as well as the more conventional optical interference methods. A discussion of the applications of these coatings to fulfill Air Force coatings needs in this area is also given.
Kaplan Turbine Blade-Operating Mechanism Without Oil Head
Authors: Sproule R. S. , Smallridge C. G.
Published: January 2012

The traditional operating mechanism of Kaplan turbine blades involves an external power supply transmitted to the runner hub by oil pressure. In the Carillon turbines the only connections to the hub are a flexible electric cable and a mechanical valve-operating rod. Elimination of the oil supply lines has been achieved by reducing the power requirement for moving the blades, by use of roller bearings and slow blade operation, and by providing suitable means of energy conversion within the hub. The paper describes the mechanism used and gives first field data on blade torques.
Condensation in a Variable Acceleration Field and the Condensing Thermosyphon
Authors: Chato J. C.
Published: January 2012

The general problem of condensation in a variable acceleration field was investigated analytically. The case of the linear variation, which occurs in a constant cross section, rotating thermosyphon, was treated in detail. The results show that the condensate thickness and Nusselt numbers approach limiting values as the radial distance increases. The effects of the temperature differential and the Prandtl number are similar to those in other condensation problems; i.e., the heat transfer increases slightly with increasing temperature differential if Pr > 1, but it decreases with increasing temperature differential if Pr ≪ 1.
Effects of Particle Injection on Natural Gas Flame Radiation
Authors: DeWerth Douglas W. , Zalavadia Jayant V.
Published: January 2012

Different methods of increasing radiant heat transfer from natural gas flames are discussed. Data are presented on the radiant heat release from an industrial-size horizontal natural gas flame at various distances from the burner head in an experimental insulating-brick furnace. Effects of the addition of combustible and noncombustible particles on natural gas flame radiation are described. Data on flame radiation from an experimental cracking and mixing burner are presented and compared with conventional luminous gas-burner flame radiation.
Electric Hydraulic Governor Control for Industrial and Commercial Gas Turbine Use
Authors: Alvis N. G.
Published: January 2012

This paper covers the latest applications of an electric hydraulic governor control for industrial-commercial gas turbine use. Gas turbines are now being used for mechanical loads, electrical power generation, and ship propulsion. Many of these applications require some degree of automatic operation and operation with other types of prime movers. The electric governor has aided this new concept in gas turbine application. Several typical installations are discussed, including both industrial and commercial use.
A Fresh Look at the Mechanism of Corrosion in Boilers
Authors: Rivers H. M.
Published: January 2012

Block specimen, hydrogen effusion, and model boiler experiments have shown that mild steel, after a brief period of “flash” oxidation immediately following immersion in aqueous solution, either corrodes relatively slowly with the formation of a thin, corrosion-resistant magnetite film, or corrosion proceeds rapidly with the development of a non-protective accumulation of iron oxide. In the latter case, film-destructive mechanisms induced experimentally by combinations of high temperature, stress, and quite high concentrations of hydroxide alkalinity or ferrous chloride have produced examples of generalized severe metal loss, pitting, heavy oxide accumulation, and hydrogen damage remarkably similar to corrosion manifestations responsible for metal failure in real boilers.