bluuebunny/crossref_metadata_2025 huggingface dataset:
Aeroelastic Instabilities in Labyrinth Air Seal Systems
Authors: Srinivasan A. V. , Arnoldi R. A. , Dennis A. J.
Published: April 2015

An analysis is developed that can be used to calculate the aeroelastic instabilities of labyrinth air seal systems. The formulation considers both the stator and rotor as flexible components and the fluid within the cavity has both axial and swirl components of velocity. The interaction of the leakage flow (through the clearance between lips of the seal and the stator) with the vibratory modes of the rotor and stator provides the mechanism for possible aeroelastic instability.

A limited parametric study shows that increasing the stiffness of either the rotor or the stator has the same stabilizing influence as including, in the analysis, swirl flow component of the leakage flow. Further, at frequencies where coincidence between stator and rotor modes occurs, there could be a sharp drop in available aerodynamic damping. These results, which need experimental confirmation, can influence the design of these important components of jet engines.
Turbomachinery Engineering and Optimization for 25 MW and 50 MW Compressed Air Energy Storage Systems
Authors: Schainker Robert , Nakhamkin Michael , Stange John R. , Giannuzzi Louis F.
Published: April 2015

Results of engineering and optimization of 25 MW and 50 MW turbomachinery trains for compressed air energy storage (CAES) power plant application are presented. Submitted by equipment suppliers, proposals are based on the commercially available equipment. Performance data and budget prices indicate that the CAES power plant is one of the most cost effective sources of providing peaking power and load management.
Three-Dimensional Modeling of Reacting Flows in Horseshoe Vortex Combustors
Authors: Turan A. , Ruggieri N. G. , Smith G. E. , Forbes B. C.
Published: April 2015

AVCO Lycoming’s circumferentially stirred combustor employs a well-established vortex, in the shape of a horseshoe with fuel injected at the apex, to promote mixing in each sector of the annulus. This paper presents the results from three-dimensional viscous flow analyses of the reacting flow field in this type of combustor. Three designs are examined — an idealized design, used for investigating how to implement the concept, and two real designs. The analytical results agree well with test results for the real designs. Of greater engineering interest, however, the analytical results reveal how the real designs work differently from the idealized design, and they explain why the two real designs contrast sharply with one another in performance.
Factors Affecting the Economics of Small, Free-Standing Cogeneration Systems
Authors: Flint Brilsford B. , El-Masri Maher A.
Published: April 2015

Samples of thermal and electric loads for four hospitals were used to evaluate cogeneration potential. The size range was one-half to three MWe, and the units were assumed free-standing in the sense that surplus power buyback by utilities was not considered. Discounted cash flow analysis was applied to calculate Return on Investment (ROI). Using typical values for the installed equipment cost, fuel cost and financing variables ROI was found to range from 25% to 90%. The sensitivity of ROI to eight system and pricing variables and five financing variables is reported. The ROI was found to be most sensitive to electricity price. The sensitivity to thermal efficiency of the engine was low provided that the efficiency was in the 20%–30% range. This suggests that moderate-performance high reliability gas turbines are the most suitable for this application.
Advanced Cooled First Stage Vane Design
Authors: Levari G. N. , Jeffries R. E. , Cohn A.
Published: April 2015

This paper discusses the design of an advanced cooled 1st stage vane, including airfoil and endwalls, for a full-scale utility combustion turbine. Shell/spar cooling technology is used, in which cooling air flows through channels between a thin metal external sheet (shell) and a hollow-cast internal support member (spar), which are joined by diffusion bonding. Heat transfer and stress analyses of this design are featured; however, design criteria, fabrication considerations, material selection, flow analysis, and future program direction are also discussed.
Load Duration Characteristics and Cogeneration Analysis
Authors: Polsky Michael P.
Published: April 2015

This paper describes the importance of accurate calculation of thermal and electrical energy production by cogeneration plants on the overall validity of cogeneration projects. A new simple graphical method which improves the accuracy of calculation of annual thermal and electrical energy consumption and production by various energy sources is proposed. A practical example of developing annual load duration characteristic using the proposed method is provided. Several illustrative graphs are included.

Evaluating the feasibility of an energy conservation project normally involves comparing of the saved operating cost with the additional capital costs required to implement the project. Operating costs, which can also be called running costs, include energy costs and equipment operating and maintenance costs. Normally, energy costs represent a major part of the running costs and, therefore, are the major factors affecting the overall profitability of the project. It almost goes without saying that an economic analysis of an energy conservation project is much more sensitive to the variations in the cost of energy than to changes in the capital costs. It is quite common that a 10 percent change in the energy cost can produce dramatic economic changes, while the same or a much larger change in the capital cost often has only a marginal effect on the economics.
The Use of Tandem Ejector Pumps in an Intermittent Blowdown Tunnel
Authors: Barnes N. C. , King P. I. , Oldfield M. L. G. , Daniels L. C.
Published: April 2015

A tandem ejector pumping system has been applied to an intermittent blowdown tunnel for cascade testing to achieve sub-atmospheric exit pressures and extend the operating range substantially. The ejectors are run from the same supply as the tunnel itself, but because they are only used at low Reynolds numbers when the cascade mass flow is small the overall running costs are kept low. A conventional one-dimensional ejector theory is developed in a new way for such an application as this, where the driving mass flow needs to be known for constant Mach number of the driven stream (the cascade exit Mach number). Several ejector geometries were tested in various configurations in a one-tenth scale model before the prototype ejectors were developed. It is demonstrated that by suitable grouping of terms it is possible to correlate both model and prototype ejector performance, and that this performance can be predicted sufficiently accurately by the theoretical model to justify its use as a design tool.

The method of operating two ejectors in tandem depends on the interaction of the exit stream of the first (forming the driven stream of the second) and the driver stream of the second. This is not immediately obvious, and is discussed fully in the light of the achieved performance.
Comparison of Different Small Steam Turbines for Steam Turbocharger
Authors: Rautenberg M. , Mobarak A. , Kader M. Abdel , Meyer C.
Published: April 2015

As a consequence of the high cost of energy, waste heat recovery schemes are becoming more attractive. One such scheme is a Rankine cycle utilizing steam as a working fluid and exhaust gases from petrol or diesel engine as a heat source. The turbine is connected with radial compressor to supercharge the engine. Turbines for this steam turbocharger in the range from 5 to 15 kW are not of the conventional type and require special design. To attain high cycle effeciency of the Rankine cycle for power systems of small capacity, the enthalpy drop should be as high as possible. This results in low mass flow rates obtained by the use of partial admission usually associated with low efficiencies. To avoid the use of partial admission, in the present work a simple Hero steam turbine with radial outward flow direction is used. Also some other designs are discussed and the efficiencies of these different types are compared. The choice of the main parameters of these turbines are very important in order to obtain the maximum possible efficiency. A method is presented for the analyses and design of simple construction.
Test Installation for the SM1A Marine Spey at RAE (Pyestock)
Authors: Kingsland J. M.
Published: April 2015

When full development of the SM1A started in 1977, plans were drawn up for an installation in the Admiralty Test House at Pyestock, for trials similar to those carried out there for the Marine Tyne and Olympus. This paper describes the design and construction of the installation, associated work to update the existing test house services and systems, and refers to alternative plans which were considered.
Effects of Nonuniform Flow Distribution on Marine Gas Turbine Waste-Heat Steam Generators
Authors: Shu Ho-Tien , Kuo Simion C. , Ellingsworth M. Keith
Published: April 2015

The results of a study to investigate the effect of nonuniform gas flow distribution on the design and performance of gas turbine waste-heat steam generators particularly for marine propulsion applications are presented. Also included are a review of major design requirements and critical problems associated with nonuniform flow distribution in waste-heat steam generators and a two-dimensional heat exchanger model developed for parametric design and performance analysis of gas turbine waste-heat steam generators. This study is based on actual gas flow distribution data measured at the exit of the collector box for a typical marine gas turbine operated at full and half power conditions. The results indicate that 1) the overall heat transfer rate of a steam generator with nonuniform inlet flow is approximately 16% less than that obtainable based on uniform flow distribution, which represents a decrease in the exit steam temperature from 700 to 450 F; and 2) with appropriate flow distribution controls (using one flow guide vane and one location for flow injection to suppress boundary layer separation), the steam generator performance can be improved by approximately 20% as compared with that for the uncontrolled nonuniform flow conditions.
Corrosion and Corrosion Control in Gas Turbines: Part I — The Compressor Section
Authors: Kolkman H. J. , Mom A. J. A.
Published: April 2015

Corrosion processes in the compressor and turbine section of a gas turbine are basically different and are treated separately. The subject of this first paper is the compressor section.

Firstly, the conditions controlling the corrosion behaviour in the compressor are considered. Next the different forms of corrosion in compressors and the various methods to combat these corrosion processes are considered. Special attention is paid to:

•rinsing and washing

•the properties of protective coatings with regard to corrosion and erosion.

Corrosion processes in the turbine section are discussed in part II.
CT7-5A/7/7E Turboprop Engine for Commuter Airline Service
Authors: Stewart J. D.
Published: April 2015

To meet the requirements of the growing commuter airline market, General Electric has developed the 1700 SHP Class CT7 Turboprop family of engines derived from the current T700/CT7 Turboshaft engines. This Turboshaft family has accumulated over 300,000 hours of successful operation.

This paper discusses the engine performance and how, through the use of advanced technology, the engine has achieved specific fuel consumption better than other engines in this class. Design maturity of the T700/CT7 family of engines has been achieved by extensive factory testing prior to production introduction and has resulted in engine reliability substantially greater than earlier engines.

A description of the component redesign of the compressor, high and low pressure turbines and the inlet system is included. The design of the propeller gearbox is also discussed. The development program through certification is covered as well as information on the CT7-5A/Grumman G1 Flight Test.
Sulfur Retention of North Dakota (Beulah) Lignite Ash in P.F.B.C.
Authors: Zakkay V. , Clisset H. , Ganesh A. , Radhakrishnan P. , Sellakumar K.
Published: April 2015

New York University (NYU), under a Department of Energy (DOE) contract, has designed and constructed a sub-pilot scale Pressurized Fluidized-Bed Combustor (PFBC) Facility at the Antonio Ferri Laboratories, Westbury, Long Island. The basic feature of this experimental research facility is a well-instrumented, 780 mm diameter coal combustor capable of operating up to 1010 kPa and provided with a liberal number of ports, making it a versatile unit for study of fundamental in-bed phenomena. Further, the overall design features make it a flexible facility for solving a variety of industrial research problems. The main objectives of the facility are three-fold:

(1) to develop fundamental data and correlations in the fluid mechanics and combustion process in PFBC;

(2) to perform research in important areas of pressurized fluidized bed-combustion, like low-grade fuel combustion under pressure; and (3) to provide the PFBC community with an experimental research tool for basic and applied research in order to accelerate the commercialization of this technology.

The facility started its shakedown tests utilizing bituminous coal in September, 1982. Subsequently, experimental research was, and is, being conducted in the combustion of North Dakota lignite at 710 k Pa.

The results presented in this paper describe the research recently obtained with tests conducted at pressurized conditions (710 k Pa)utilizing North Dakota lignite. Preliminary results indicate that the agglomeration process may be suppressed due to the higher pressure.

In addition, the research indicates than an inert bed material could be used in the combustion process for controlling SO2 emissions. This is attributed to the alkali compounds present within the ash of the lignite. The research also indicates that SO2 emissions could be controlled by varying the excess air.
Engineering Ceramics for Industrial Applications; Wear-, Heat- and Automotive Technology
Authors: Krauth A. , Berroth K.
Published: April 2015

Material type, process technology and major properties for four ceramic components mass produced during the last three years are described. Table A-1 defines the components, material type and fabrication method. Table A-2 summarizes the density, bend strength, Weibull modulus and as fired dimensional tolerances. Production parts with flaws detectable by lox visual examination are not included in the tabulated data.
The Design and Development of a New 7 to 13.5 MW Industrial Two Shaft Gas Turbine (CW182)
Authors: McQuiggan G.
Published: April 2015

This paper describes the design and development of the CW182 two shaft variable geometry industrial gas turbine. This gas turbine is a scaled down version of the existing CW352 gas turbine.

The methods used to scale the gas turbine are explained together with a detailed description of those areas that were not scaled but were completely redesigned. In addition, details of the testing carried out on the new design components are described.
Rotating Stall Caused by Pressure Surface Flow Separation on Centrifugal Fan Blades
Authors: Madhavan Suresh , Wright Terry
Published: April 2015

A rotating stall associated with massive flow separation on the pressure surface (p-stall) of a centrifugal fan blade is identified. The stall cell rotates in the same sense as the rotation of the impeller. The frequency of pressure pulsation is greater than the running frequency and approaches 4/3rds the running frequency. It is proposed that the mechanism of p-stall propagation is similar to that of the classical rotating stall caused by flow separation on the suction surface (s-stall). However, it is emphasized that the cause of p-stall is different from s-stall and any corrective treatment applied should take its nature into consideration. In the present work, pressure surface stall was induced by pre-rotating the inlet flow using inlet guide vanes and operating the fan against a low system resistance. Heuristic models are proposed for the inception and propagation of p-stall, and computational predictions of the flow fields, along with experimental results, are presented to support the model.
The Development of the High Energy Surface Discharge Spark Igniter
Authors: Burland G. N. , Goreham K. A. , Taunt R. J.
Published: April 2015

The High Energy Igniter is discussed from the point of view of its mechanism of operation and of factors which determine its operational life. Features of the engine environment and operation are considered in their effect on igniter life. The problems associated with continuous ignition and the overriding importance of the quality of the surface discharge material are discussed. The development of a new surface discharge ceramic is described.
Integration of the Brayton and Rankine Cycle to Maximize Gas Turbine Performance: A Cogeneration Option
Authors: Messerlie R. L. , Strother J. R.
Published: April 2015

The Brayton and Rankine cycles are well known and widely used in their own way to generate power. A combining of the fluids of the two cycles has been proposed by International Power Technology and tested by Allison Gas Turbine Operations. Steam generated by the exhaust heat is mixed with the fuel and air in the gas turbine combustion chamber prior to expansion through the turbine.

The thermal efficiency of an existing engine can be increased by 40% and power output by 60% at constant turbine temperature. This concept is identified as the Dual Fluid Cycle (DFC).

In addition to the basic improvement in cycle performance, the DFC provides an added degree of flexibility to the power plant engineer in his effort to satisfy plant needs for power, heat, and steam.

Allison test results of this concept on a Model 501-KB engine have been correlated with a computer model of the engine and show good agreement. This paper will show how the DFC can be used to maximize thermal efficiency while meeting the requirement for power and steam in selected cases. Comparisons will be made to other options for power and steam generation.
Development of the PGT 25 High Efficiency Gas Turbine: Part 2 — Aerodynamic Design and Performance
Authors: Benvenuti E. , Innocenti B. , Modi R.
Published: April 2015

This paper outlines parameter selection criteria and major procedures used in the PGT 25 gas turbine power spool aerodynamic design; significant results of the shop full-load tests are also illustrated with reference to both overall performance and internal flow-field measurements.

A major aero-design objective was established as that of achieving the highest overall performance levels possible with the matching to latest generation aero-derivative gas generators; therefore, high efficiencies were set as a target both for the design point and for a wide range of operating conditions, to optimize the turbine’s uses in mechanical drive applications. Furthermore, the design was developed to reach the performance targets in conjunction with the availability of a nominal shaft speed optimized for the direct drive of pipeline booster centrifugal compressors.

The results of the full-load performance testing of the first unit, equipped with a General Electric LM 2500/30 gas generator, showed full attainment of the design objectives; a maximum overall thermal efficiency exceeding 37% at nominal rating and a wide operating flexibility with regard to both efficiency and power were demonstrated.
Development of the PGT 25 High Efficiency Gas Turbine: Part 3 — Experimental Program and Testing
Authors: Lacitignola P. , Valentini E.
Published: April 2015

This paper presents a review of the engineering testing program related to development of the PGT-25 gas turbine.

The experimental methods employed and their capability of providing information for the tuning of the engine and its parts are discussed.

Testing has continuously supported turbine design and development; integration of analytical and experimental procedures has proven to be efficient for successful final engine testing.

Full load testing, using well developed instrumentation, has made it possible to know actual component behavior and engine performance in steady and transient states, over the entire speed and power range.

The reliability of the machine has been assessed through the results of these tests.
The Thermal Stability of Aviation Fuel
Authors: Mills J. S. , Edwards F. R.
Published: April 2015

The propensity of aviation turbine fuels to produce deposits in the oil-cooler and filter sections of aircraft fuel systems has been examined using a rig that simulates the fuel system of an aircraft and which employs realistic flow rates. All the fuels examined were found to be thermally stable up to temperatures in excess of those currently attained in engine oil coolers. Comparison with results obtained with the JFTOT indicates that this is not suited for use as a research tool.
Corneal infection byPseudomonas stutzerifollowing excision of trigeminal nerve schwannoma
Authors: Kalra Deepak , Sati Alok , Shankar Sandeep , Jha Ashok
Published: April 2015

A 25-year-old woman underwent intracranial surgery for trigeminal nerve schwannoma (TGNS) with persistent left-sided facial hypoaesthesia. Two months later, she developed a central corneal ulceration. Scraping of the corneal lesion revealed Gram-negative bacilli. Genus level identification was achieved using standard techniques and species level identification, revealingPseudomonas stutzeri, was aided by a VITEK 2 compact system. Broad-spectrum fortified antibiotics were initially started followed by species-sensitive fortified antibiotics. Ocular surface toxicity developed a week later; this was managed with a non-fortified antibiotic. The epithelial defect healed in 3 weeks with subsequent corneal scar formation. Visual rehabilitation was achieved with deep anterior lamellar keratoplasty. Six months following surgery, the patient had a visual acuity of 20/40 with −1.25 170° −0.5 refractive correction and a clear graft. This case report, for the first time, highlightsP. stutzeri, an aetiological agent of corneal ulcer following excision of TGNS and its successful management.
Football injuries during the 2014 FIFA World Cup
Authors: Junge Astrid , Dvořák Jiri
Published: April 2015

Background

FIFA has surveyed match injuries in its tournaments since 1998.

Aim

To analyse the incidence and characteristics of match injuries incurred during the 2014 FIFA World Cup in comparison to previous FIFA World Cups.

Methods

The chief physicians of the participating teams reported all newly incurred injuries of their players after the match on a standardised report form. 124 (97%) forms were returned.

Results

A total of 104 injuries were reported, equivalent to an incidence of 1.68 injuries per match (95% CI 1.36 to 2.00). 64 (63.4%) injuries were caused by contact with another player. Thigh (26; 25%) and head (19; 18%) were the most frequently injured body parts. The most frequent diagnosis was thigh strain (n=18). Five concussions and three fractures to the head were reported. While most thigh strains (15/17; 88.2%) occurred without contact, almost all head injuries (18/19; 94.7%) were caused by contact. 0.97 injuries per match (95% CI 0.72 to 1.22) were expected to result in absence from training or match. Eight injuries were classified as severe. The incidence of match injuries in the 2014 FIFA World Cup was significantly lower than the average of the four preceding FIFA World Cups, both for all injuries (2.34; 95% CI 2.15 to 2.53) and time-loss injuries (1.51; 95% CI 1.37 to 1.65).

Conclusions

The overall incidence of injury during the FIFA World Cups decreased from 2002 to 2014 by 37%. A detailed analysis of the injury mechanism is recommended to further improve prevention strategies.
FIFA 11+: an effective programme to prevent football injuries in various player groups worldwide—a narrative review
Authors: Bizzini Mario , Dvorak Jiri
Published: April 2015

In 2009, FIFA promoted and disseminated the FIFA 11+ injury prevention programme worldwide. Developed and studied by the FIFA Medical Assessment and Research Centre (F-MARC), the programme was based on a randomised controlled study and one countrywide campaign in amateur football that significantly reduced injuries and healthcare costs. Since the FIFA 11+ launch, key publications have confirmed the preventive effects of the programme and have evaluated its performance effects in female as well as male amateur football players. Furthermore, implementation strategies of this prevention programme have also been studied. The goal of this narrative review was to summarise the available scientific evidence about the FIFA 11+ programme. While FIFA continues to disseminate and implement FIFA 11+ among its Member Associations, adaptations of the injury prevention programme for children and referees have been developed and are currently being evaluated.
Recreational football for disease prevention and treatment in untrained men: a narrative review examining cardiovascular health, lipid profile, body composition, muscle strength and functional capacity
Authors: Bangsbo Jens , Hansen Peter Riis , Dvorak Jiri , Krustrup Peter
Published: April 2015

Over the past 10 years, researchers have studied the effects of recreational football training as a health-promoting activity for participants across the lifespan. This has important public health implications as over 400 million people play football annually. Results from the first randomised controlled trial, published in theBJSMin January 2009, showed that football increased maximal oxygen uptake and muscle and bone mass, and lowered fat percentage and blood pressure, in untrained men, and since then more than 70 articles about football for health have been published, including publications in two supplements of theScandinavian Journal of Medicine and Science in Sportsin 2010 and 2014, prior to the FIFA World Cup tournaments in South Africa and Brazil. While studies of football training effects have also been performed in women and children, this article reviews the current evidence linking recreational football training with favourable effects in the prevention and treatment of disease in adult men.
Evaluation of tumour vaccine immunotherapy for the treatment of advanced non-small cell lung cancer: a systematic meta-analysis
Authors: Wang Min , Cao Jun-Xia , Liu Yi-Shan , Xu Bei-Lei , Li Duo , Zhang Xiao-Yan , Li Jun-Li , Liu Jin-Long , Wang Hai-Bo , Wang Zheng-Xu
Published: April 2015

Objectives

Our meta-analysis performed a systematic evaluation on the therapeutic efficacy and safety of tumour vaccines for the treatment of advanced non-small cell lung cancer (NSCLC).

Design

Systematic review and meta-analysis of randomised controlled trials (RCT).

Data sources

PubMed, the Cochrane Center Register of Controlled Trials, Science Direct and EMBASE were searched from January 1980 until January 2015.

Eligibility criteria for selecting studies

RCT were included; the control arm had to receive either placebo or chemotherapy or no treatment.

Main outcome measures

The quality of the data from individual papers was assessed for overall survival (OS), clinical response rate and side effects.

Results

Overall, 11 RCT of advanced NSCLC with a total of 3986 patients were conducted for meta-analysis. The results showed that the vaccine arm significantly extended primary endpoint median overall survival compared with control group (p<0.00001) (HR 0.760; 95% CI 0.644 to 0.896; p=0.001). Three subgroup patients with tumour vaccine at 1-year, 2-year and 3-year survival rates also gained significant benefits compared with their corresponding control group (p=0.0004, 0.03 and 0.19, respectively). Besides, a significant improvement in median time to progression (TTP), median progression-free survival (PFS) and a trend of improvement in objective response rate were observed after tumour vaccine treatment (p=0.001, 0.005 and 0.05, respectively; median PFS HR 0.842; 95% CI 0.744 to 0.954; p=0.007). A few severe adverse effects occurred in the tumour vaccine group, but fewer side effects were observed in the vaccine group compared with the control group (p<0.00001).

Conclusions

Taken together, NSCLC tumour vaccines markedly prolong median OS (p<0.00001), median TTP (p=0.001) and median PFS (p=0.005), improve clinical response rate (p=0.05) and lessen adverse side effects (p<0.00001). Our meta-analysis suggests tumour vaccines improve the efficacy of the treatment, and also provide superiority in treatment of patients with advanced NSCLC among a variety of immunotherapy strategies.
Inner conflict in patients receiving oral anticancer agents: a qualitative study
Authors: Yagasaki Kaori , Komatsu Hiroko , Takahashi Tsunehiro
Published: April 2015

Objectives

To explore the experiences of patients receiving oral anticancer agents.

Design

A qualitative study using semistructured interviews with a grounded theory approach.

Setting

A university hospital in Japan.

Participants

14 patients with gastric cancer who managed their cancer with oral anticancer agents.

Results

Patients with cancer experienced inner conflict between rational belief and emotional resistance to taking medication due to confrontation with cancer, doubt regarding efficacy and concerns over potential harm attached to use of the agent. Although they perceived themselves as being adherent to medication, they reported partial non-adherent behaviours. The patients reassessed their lives through the experience of inner conflict and, ultimately, they recognised their role in medication therapy.

Conclusions

Patients with cancer experienced inner conflict, in which considerable emotional resistance to taking their medication affected their occasional non-adherent behaviours. In patient-centred care, it is imperative that healthcare providers understand patients’ inner conflict and inconsistency between their subjective view and behaviour to support patient adherence.
Flow simulation over oblique cylindrical weirs
Authors: Yuce Mehmet Ishak , Al-Babely Aemad A.H. , Al-Dabbagh Mohammad A.
Published: April 2015

This paper presents a computational fluid dynamics (CFD) simulation to investigate the effects of the obliqueness of cylindrical weirs on the flow velocity distribution, the pressure distribution and the distribution of water depth over the weir crest. Three different cylindrical weirs with diameters of 0.114 m, 0.09 m, and 0.0635 m, with three dissimilar inclination angles of 90°, 135°, and 150° were used. The SSG Reynolds stress turbulence closure model was utilized in the analyses. The results show that the flow patterns are affected by the inclination angle with respect to the flow direction. It was noticed that inclination angle increment increases the velocity of flow at the downstream surface of the weir, thus increases the absolute value of the negative pressure, at the inward-moved end of the weir. The outward-moved end of the weir was observed not to be covered with water and extending with the increase of the inclination angle.
Current capacity to conduct ecologically sustainable forest management in northeastern Canada reveals challenges for conservation of biodiversity
Authors: Imbeau Louis , St-Laurent Martin-Hugues , Marzell Lothar , Brodeur Vincent
Published: April 2015

Long-term exploitation of boreal ecosystems often results in a reduced range of ecological conditions that threatens several species. In most boreal jurisdictions, the northern extent of commercial forestry corresponds to economical rather than ecological considerations. Our general objective is to offer guidance for sustainable boreal forest management by using a biodiversity criterion based on three indicators. The first two indicators are part of a coarse filter referring to the proportion and fragmentation of tall, dense forest habitats, whereas a third one uses a fine filter for specific requirements of boreal caribou. We applied the methodology with and without anthropogenic disturbances on 1114 land districts to contrast the preindustrial potential and current capacity of Quebec’s boreal forest to support forest management. Originally, 826 districts (74%) were above the 20% cutoff value for the minimum proportion of tall, dense forest habitats. Among the 567 districts currently under forest management, 45 did not reach this value because of past anthropogenic disturbances. Originally, 88% of the districts had sufficient undisturbed habitats to maintain caribou populations, but anthropogenic disturbances reduced this proportion to 51%. The proposed methodology could contribute to delineating areas where sustainable forest management can be implemented. Our results also clearly show that management targets of the last decades were insufficient to prevent loss of habitats below strict minimum ecological thresholds. Our approach offers a general framework that could be adapted to other forested regions to attain similar biodiversity conservation objectives.
Contrasting current and potential productivity and the influence of fire and species composition in the boreal forest: a case study in eastern Canada
Authors: Rapanoela Rija , Raulier Frédéric , Gauthier Sylvie , Ouzennou Hakim , Saucier Jean-Pierre , Bergeron Yves
Published: April 2015

The capacity of a forest stand to produce timber is related to the interactions that exist between its regeneration capacity, physical site characteristics (climate, surficial deposit, drainage), and disturbances. Minimally, to be sustainably managed, a forest needs to be sufficiently productive and able to regenerate after a disturbance so that its productive capacity is maintained or enhanced. To this effect, we evaluated timber productivity over a large area (175 000 km2) covering the latitudinal extent of closed-canopy black spruce (Picea mariana (Mill.) B.S.P) forest. Site index and relative density index were used to identify stands that cannot reach a minimum volume of trees of minimum size over one rotation. A nonparametric method was used to estimate their values for all stands within the study area. This imputation used either physical site attributes alone to assess potential productivity independent of stand history or physical and vegetation site attributes to assess current productivity. The proportion of productive stands was then estimated at the scale of landscapes ranging from 39 to 2491 km2. Physical site factors alone explain 84% of the variability in the percentage of potentially productive stands (78% for currently productive stands); their combination resulted in an abrupt transition in productivity over the study area. However, burn rate alone also explains 63% of variation in the proportion of currently productive stands and 41% of the relative difference between percentages of potentially or currently productive stands. These results have implications for strategic forest management planning at land classification stage, as timber production area is assumed to remain stable through time, whereas it is apparently related to the disturbance rate.
Extension of Grimus–Stockinger formula from operator expansion of free Green function
Authors: Korenblit S. E. , Taychenachev D. V.
Published: April 2015

The operator expansion of free Green function of Helmholtz equation for arbitrary N-dimensional space leads to asymptotic extension of three dimensions Grimus–Stockinger formula closely related to multipole expansion. Analytical examples inspired by neutrino oscillation and neutrino deficit problems are considered for relevant class of wave packets.
Effect of Vortex Induced Vibration on a Paired-Column Semisubmersible Platform
Authors: Odijie Agbomerie Charles , Ye Jianqiao
Published: April 2015

This paper describes a numerical study of the effect of vortex induced movement (VIM) on the hull of a paired-column semisubmersible (pc-semi) platform in relation to the column geometric properties. A computational fluid dynamics (CFD) analysis was carried out and vortex shedding was observed. The response of the square and rectangular columns hull configuration was investigated using ANSYS AQWA and the maximum amplitude was observed to be almost the same for both geometry, but it occurred at different range of reduced velocity Vr. The effect of surface wave and flow incidence angle were investigated for extreme and regular weather conditions, and it was found that VIM occurred at 2 ≤ Vr ≤ 12.
Seismic Fragility Analysis of Reinforced Concrete Bridges with Chloride Induced Corrosion Subjected to Spatially Varying Ground Motions
Authors: Li Chao , Hao Hong , Li Hongnan , Bi Kaiming
Published: April 2015

This paper studies the time-dependent seismic fragility of reinforced concrete bridges with chloride induced corrosion under spatially varying ground motions. The time-varying characteristic of the chloride corrosion current density and the uncertainties related to the structural, material and corrosion parameters are both considered in the probabilistic finite element modeling of the example RC bridge at different time steps during its life-cycle. Spatially varying ground motions at different bridge supports are stochastically simulated and used as inputs in the fragility analysis. Seismic fragility curves of the corroded RC bridge at different time steps are generated using the probabilistic seismic demand analysis (PSDA) method. Numerical results indicate that both chloride induced corrosion and ground motion spatial variations have a significant effect on the bridge structural seismic fragility. As compared to the intact bridge, the mean peak ground accelerations (PGAs) of the fragility curves of the RC bridge decrease by approximately 40% after 90 years since the initiation of corrosion. Moreover, the effect of ground motion spatial variations changes along with the process of chloride induced corrosion owing to the structural stiffness degradation. Neglecting seismic ground motion spatial variations may not lead to an accurate estimation of the lifetime seismic fragility of RC bridges with chloride induced corrosion.
3D Video Communication System by Using Kinect and Head Mounted Displays
Authors: Hashimoto Hideyuki , Fujibayashi Yuki , Imamura Hiroki
Published: April 2015

Existing video communication systems, used in private business or video teleconference, show a part of the body of users on display only. This situation does not have realistic sensation because of showing a part of body on display and showing other users by 2D. This makes users feel communicating with the other users at a long distance without realistic sensation. Furthermore, although these existing communication systems have file transfer function such as sending and receiving file data, it does not use intuitive manipulation. It uses mouse or touching display only. In order to solve these problems, we propose 3D communication system supported by Kinect and head mounted display (HMD) to provide users communications with realistic sensation and intuitive manipulation. This system is able to show whole body of users on HMD as if they were in the same room by 3D reconstruction. It also enables users to transfer and share information by intuitive manipulation to augmented reality (AR) objects toward the other users in the future. The result of this paper is a system that extracts human body by using Kinect, reconstructs extracted human body on HMD, and also recognizes users' hands to be able to manipulate AR objects by a hand.
Harmonic Analysis of Radon Filtrations for Sn and Its q-Analogue GLn(q)
Authors: Yáñez M. Francisca
Published: April 2015

We present a unified approach to the study of Radon transforms related to the group Sn and its q-analogue GLn(q). In both cases, in a uniform way, we define a sequence of generalized Radon transforms that are intertwining operators for natural representations associated to Gel'fand spaces for our groups. This sequence and the sequence of their adjoint enable us to decompose in a recursive way these natural representations into irreducibles and to compute explicitly the associated spherical functions. Our methods and results rely then strongly on q-analogy.
On n-Coherent Rings and (n,d)-Injective Modules
Authors: Zhang Dongdong , Ouyang Baiyu
Published: April 2015

Let R be a ring, n, d be fixed non-negative integers, [Formula: see text] the class of (n,d)-injective left R-modules, and [Formula: see text] the class of (n,d)-flat right R-modules. In this paper, we prove that if R is a left n-coherent ring and m ≥ 2, then [Formula: see text] if and only if [Formula: see text], if and only if Ext m+k(M,N) = 0 for all left R-modules M, N and all k ≥ -1, if and only if Ext m-1(M,N) = 0 for all left R-modules M, N. Meanwhile, we prove that if R is a left n-coherent ring, then − ⊗ − is right balanced on [Formula: see text] by [Formula: see text], and investigate the global right [Formula: see text]-dimension of [Formula: see text] and the global right [Formula: see text]-dimension of [Formula: see text] by right derived functors of − ⊗ −. Some known results are obtained as corollaries.
Differential fiber-specific block of nerve conduction in mammalian peripheral nerves using kilohertz electrical stimulation
Authors: Patel Yogi A. , Butera Robert J.
Published: April 2015

Kilohertz electrical stimulation (KES) has been shown to induce repeatable and reversible nerve conduction block in animal models. In this study, we characterized the ability of KES stimuli to selectively block specific components of stimulated nerve activity using in vivo preparations of the rat sciatic and vagus nerves. KES stimuli in the frequency range of 5–70 kHz and amplitudes of 0.1–3.0 mA were applied. Compound action potentials were evoked using either electrical or sensory stimulation, and block of components was assessed through direct nerve recordings and muscle force measurements. Distinct observable components of the compound action potential had unique conduction block thresholds as a function of frequency of KES. The fast component, which includes motor activity, had a monotonically increasing block threshold as a function of the KES frequency. The slow component, which includes sensory activity, showed a nonmonotonic block threshold relationship with increasing KES frequency. The distinct trends with frequency of the two components enabled selective block of one component with an appropriate choice of frequency and amplitude. These trends in threshold of the two components were similar when studying electrical stimulation and responses of the sciatic nerve, electrical stimulation and responses of the vagus nerve, and sensorimotor stimulation and responses of the sciatic nerve. This differential blocking effect of KES on specific fibers can extend the applications of KES conduction block to selective block and stimulation of neural signals for neuromodulation as well as selective control of neural circuits underlying sensorimotor function.
Mining Potential Spammers from Mobile Call Logs
Authors: Liu Zhipeng , Pi Dechang , Chen Yunfang
Published: April 2015

With the rapid development of mobile telecommunication, voice call spam has become a growing problem in China. Many mobile phone users have become the victim of spam calls and suffered heavy financial loss. Discovering of call spammers can benefit mobile network operators as well as users. Nowadays, the popular method for the task of mining call spammers has been performed by different applications on smartphones. These applications combine manual and automatic methods to detect spammers. Although the results of these client-based solutions are quite satisfying, it is extremely unfortunate that many people still use feature phones, which can not be equipped with third party applications. In this paper, we propose a server-based solution and take a call log file as an example, to analyze the characteristics of mobile call patterns. A time-based graph model and a simple and effective call log rank (CLRank) algorithm with ranking and classification were proposed to find potential call spammers. Compared with existing methods, our model just uses link information, and thus protects user privacy to the maximum extent. Experimental results show that our proposed model can find spammers from call logs automatically, dynamically, and effectively (with 84.5~91.8% of accuracy) without any manual interventions.
Patellar Tendon Rupture after Lateral Release without Predisposing Systemic Disease or Steroid Use
Authors: De Giorgi S. , Notarnicola A. , Vicenti G. , Moretti B.
Published: April 2015

Arthroscopic technique for lateral release is the most widely used procedure for the correction of recurrent dislocations of the patella. In the relevant literature, several complications of lateral release are described, but the spontaneous patellar tendon rupture has never been suggested as a possible complication of this surgical procedure. Patellar tendon rupture is a rather infrequent and often unilateral lesion. Nevertheless, in case of systemic diseases (LES, rheumatoid arthritis, and chronic renal insufficiency) that can weaken collagen structures, bilateral patellar tendon ruptures are described. We report a case of a 24-year-old girl with spontaneous rupture of patellar tendon who, at the age of 16, underwent an arthroscopic lateral release for recurrent dislocation of the patella. This is the first case of described spontaneous patellar tendon rupture that occurred some years after an arthroscopic lateral release.
Decadal Variation in Raindrop Size Distributions in Busan, Korea
Authors: You Cheol-Hwan , Lee Dong-In
Published: April 2015

This paper investigated the variability of raindrop size distributions (DSDs) in Busan, Korea, using data from two different disdrometers: a precipitation occurrence sensor system (POSS) and a particle size velocity (Parsivel) optical disdrometer. DSDs were simulated using a gamma model to assess the intercomparability of these two techniques. Annual rainfall amount was higher in 2012 than in 2002, as were the annually averagedDm(which was 0.1 mm greater in 2012) and the frequency of convective rain. Severe rainfall (greater than 20 mm h−1) occurred more frequently and with a largerDmin 2012. The values ofDmfrom July, August, and December, 2012, were much greater than from other months when compared with 2002. Larger raindrops contributed to the higher rain rates that were observed in the morning during 2012, whereas relatively smaller raindrops dominated in the afternoon. These results suggest that the increase in raindrop size that has been observed in Busan may continue in the future; however, more research will be required if we are to fully understand this phenomenon. Rainfall variables are highly dependent on drop size and so should be recalculated using the newest DSDs to allow more accurate polarimetric radar rainfall estimation.