bluuebunny/crossref_metadata_2025 huggingface dataset:
Migration timespaces: a Heideggerian approach to understanding the mobile being of Eastern Europeans in Scotland
Authors: Shubin Sergei
Published: January 2015

This article explores the spatio‐temporal experiences of Eastern Europeans during their migration to Scotland. It contributes to emerging research on times and spaces of migration by drawing on Martin Heidegger's analysis of ‘being on the move’ to challenge the prevailing objective conceptions of time and space as encountered in sequential and geometrically measurable forms. This article explores the complexity of timespaces in terms of their openness and co‐existence, and considers migrants' lives as open‐ended and incorporating a multiplicity of futures, presents and pasts. Using examples from a qualitative study in North‐East Scotland, it studies the role of uncertain transitions, moods and affects alongside certainty and rational plans in structuring migrants' being on the move. It concludes with conceptual observations about the consequences of adopting intersubjective and multiple visions of timespaces in migration research.
Financial geography: introduction to the Virtual Issue
Authors: Aalbers Manuel B
Published: January 2015

This introduction traces the development of financial geography through 15 papers selected for a Virtual Issue and previously published inTransactionsbetween 1976 and 2014. The birth of a distinctive literature on the geographies of money and finance can be traced back to the mid 1990s, althoughTransactionspublished a few earlier papers dealing with building societies and international lending. Other finance‐related topics of interest include: retail banking, financial exclusion, local exchange trading systems, venture capital investments, emerging markets, Islamic banking, pension funds, sovereign wealth funds, financial crises, tourism and mining. While British financial geography dominates the literature in the early years, other countries and international financial flows slowly enter the debate. Although financial geographies are slowly being decentred and rescaled, more work is needed to make the literature more inclusive and geographically diverse. Financial geography built originally on work in economic geography, political economy, urban geography and political geography, but later also includes cultural economy and social studies of finance. Finally, the financial geography literature has established itself within geography and increasingly also within interdisciplinary and pluralistic political and cultural economy.
Do Developing‐country WTO Members Receive More Aid for Trade (AfT)?
Authors: Lee Hyun‐Hoon , Park Donghyun , Shin Meehwa
Published: January 2015

Since the World Trade Organization (WTO) Doha Development Agenda (DDA) negotiations started in 2001, the importance of aid for trade (AfT) has been well recognised as a useful tool for facilitating trade, economic growth and social development in developing countries. At the WTO Hong Kong Ministerial Conference in December 2005, the ‘AfT initiative’ was launched and many high‐income member countries pledged to increase their AfT contributions, particularly for the least developed member countries (LDC). This paper aims to assess whether and to what extent the WTO's developing member countries have received more AfT. For this purpose, a system generalised method of moments is applied to a sample of 118 recipient countries for the period 2001–10. We find evidence that while LDC WTO members on average receive relatively more AfT than other developing countries, the difference has not increased since launch of the AfT initiative. Among the three categories of AfT, the positive WTO membership effect for LDC members increased for building productive capacity and for trade policy and regulation, but declined for infrastructure.
The Effect of Streamtube Contraction on the Characteristics of a Streamwise Vortex
Authors: McLelland Grant , MacManus David , Sheaf Chris
Published: January 2015

The ingestion of a vortex by an aero-engine is potentially an area of concern for current and future aircraft-engine configurations. However, there are very little experimental data on the characteristics of a streamwise vortex undergoing ingestion through a contracting streamtube. To address this dearth of knowledge, the ingestion of a streamwise vortex has been studied experimentally using stereoscopic particle image velocimetry (stereo PIV). A subscale model of an aircraft intake has been used to generate a contracting capture streamtube, and an isolated streamwise vortex has been generated upstream of the intake using semispan NACA 0012 and delta wing vortex generators (VGs). A range of contraction ratios, vortex Reynolds numbers, and vortex initial conditions have been examined. Measurements on planes perpendicular to the freestream flow show that the vortex undergoes notable levels of intensification through the contraction streamtube. The characteristics of the vortex are dependent on the streamtube contraction level, the initial aerodynamic characteristics of the vortex, and the trajectory that the vortex follows inside the capture streamtube. Results from inviscid, incompressible vortex filament theory have been compared with the experimental data. At relatively low streamtube contraction ratios this theory provides a good estimate of the vortex characteristics. However, at higher contraction levels, there are notable levels of diffusion, which render the vortex less intense than that anticipated from vortex filament theory.
Stability Analysis of Sliding–Grazing Phenomenon in Dry-Friction Oscillator Using Takagi–Sugeno Fuzzy Approach
Authors: Mehran Kamyar , Zahawi Bashar , Giaouris Damian , Wang Jihong
Published: January 2015

Dry-friction oscillators are mechanical systems with dry friction and stick-slip vibrations. In the context of control theory, the stability analysis of this type of dynamical systems is important since they exhibit nonsmooth bifurcations, or most famously a sliding–grazing bifurcation inducing abrupt chaos. This paper develops a Lyapunov-based framework to study the so-called structural stability of the system, predicting the onset of such unique bifurcations. To achieve this, the nonlinear system is first represented as a nonsmooth Takagi–Sugeno (TS) fuzzy model, and the structural stability is then formulated as linear matrix inequalities (LMI) feasibility problems with less conservative formulation. Solving the resulting LMI problem, the onset of sliding–grazing bifurcation can be accurately predicted.
Docking Robustness of Patient Specific Surgical Guides for Joint Replacement Surgery
Authors: Mattheijer Joost , Herder Just L. , Tuijthof Gabriëlle J. M. , Valstar Edward R.
Published: January 2015

In joint replacement surgery, patient specific surgical guides (PSSGs) are used for accurate alignment of implant components. PSSGs are designed preoperatively to have a geometric fit with the patient's bone such that the incorporated guidance for drilling and cutting is instantly aligned. The surgeon keeps the PSSG in position with a pushing force, and it is essential that this position is maintained while drilling or cutting. Hence, the influence of the location and direction of the pushing force should be minimal. The extent that the pushing force may vary is what we refer to as docking robustness. In this article, we present a docking robustness framework comprising the following quantitative measures and graphical tool. Contact efficiency ηc is used for the quantification of the selected bone–guide contact. Guide efficiency ηg is used for the quantification of the whole guide including an application surface whereon the surgeon can push. Robustness maps are used to find a robust location for the application surface based on gradient colors. Robustness R is a measure indicating what angular deviation is minimally allowed at the worst point on the application surface. The robustness framework is utilized in an optimization of PSSG dimensions for the distal femur. This optimization shows that 12 contacts already result in a relatively high contact efficiency of 0.74 ± 0.02 (where the maximum of 1.00 is obtained when the guide is designed for full bone–guide contact). Six contacts seem to be insufficient as the obtained contact efficiency is only 0.18 ± 0.02.
Flow Visualization of a Jet Impinging on a Ribbed Surface With Crossflow
Authors: Haiping Chang , Jingyu Zhang , Taiping Huang , Dalin Zhang
Published: January 2015

The flow behavior of a jet impinging on a ribbed surface has an obvious effect on the impingement heat transfer. It has been observed experimentally in a special smoke wind tunnel with rectangular section. This is an interesting problem in the impingement cooling midchord region of the gas turbine aerofoils with ribbed surface, and also in the electronic component cooling. The effect of the structural parameters, such as rib height (e), pitch-to-height ratio (p/e), nondimensional jet-to-surface spacing (Z/d) and the relative position of the jet hole to the ribs etc., and the crossflow rate on the flow behavior have been investigated by the flow visualization on a variety of configuration models. The experimental results reveal the mechanism of flow behavior and explain the flow and heat transfer characteristics of the impingement cooling from ribbed surface with crossflow.
Westinghouse Status of Coal and Biomass Fueled Combustion Turbine Systems for Power Generation
Authors: Bannister Ronald L. , Newby Richard A. , Lippert Thomas E.
Published: January 2015

Coal and biomass are of interest today as alternatives to conventional combustion turbine fuels. Significant processing is required for these fuels to be used in combustion turbine applications. Westinghouse is developing and demonstrating technologies for fuel processing, hot gas cleaning, and fuel gas combustion, and is assessing combustion turbine adaptations for coal and biomass fuels. This paper reviews the status of Westinghouse development and demonstration activities for the use of coal and biomass fuels in advanced power generation systems incorporating combustion turbines for pressurized fluidized bed combustion (PFBC), integrated gasification combined cycles (IGCC), and direct coal-fired (DCF) cycle configurations.
Detailed Measurement of Convective Heat Transfer in Rotating Two-Pass Rib-Roughened Coolant Channels
Authors: Mochizuki S. , Beier M. , Murata A. , Okamura T. , Hashidate Y.
Published: January 2015

The objective of the study is to investigate, through experiments, heat transfer characteristics in a rotating two-pass rib-roughened coolant channel with a sharp 180-deg turn. Detailed measurements of local surface temperatures of the coolant channel are conducted using a newly designed and constructed test section which has as many as 458 thermocouples installed on the rotating channel walls. Description of this unique experimental rig is given. The cross section of the channel is rectangular with 15 mm in width and 30 mm in height. In addition to a rib-free (smooth) surface, two types of rib configurations are employed: 90° and 45° parallel ribs. The measured temperature distribution for the entire test section are shown and the effects of rib configuration and rotation on the cooling performance are examined. It was also found that the secondary flow created in the bend has substantial influence on the heat transfer in the channel after the turning section.
Heat Transfer Predictions for U-Shaped Coolant Channels With Skewed Ribs and With Smooth Walls
Authors: Bonhoff Bernhard , Tomm Uwe , Johnson Bruce V.
Published: January 2015

A computational study was performed for the flow and heat transfer in coolant passages with two legs connected with a U-bend and with dimensionless flow conditions typical of those in the internal cooling passages of turbine blades. The first model had smooth surfaces on all walls. The second model had opposing ribs staggered and angled at 45° to the main flow direction on two walls of the legs, corresponding to the coolant passage surfaces adjacent to the pressure and suction surfaces of a turbine airfoil. For the ribbed model, the ratio of rib height to duct hydraulic diameter equaled 0.1, and the ratio of rib spacing to rib height equaled 10. Comparisons of calculations with previous measurements are made for a Reynolds number of 25,000. With these conditions, the predicted heat transfer is known to be strongly influenced by the turbulence and wall models. The k-e model, the low Reynolds number RNG k-e and the differential Reynolds-stress model (RSM) were used for the smooth wall model calculation. Based on the results with the smooth walls, the calculations for the ribbed walls were performed using the RSM and k-e turbulence models. The high secondary flow induced by the ribs leads to an increased heat transfer in both legs. However, the heat transfer was nearly unchanged between the smooth wall model and the ribbed model within the bend region. The agreement between the predicted segment-averaged and previously-measured Nusselt numbers was good for both cases.
45° Staggered Rib Heat Transfer Coefficient Measurements in a Square Channel
Authors: Taslim M. E. , Lengkong A.
Published: January 2015

For high blockage ribs with large heat transfer areas, commonly used in small gas turbine blades, the rib heat transfer is a significant portion of the overall heat transfer in the cooling passages. Three staggered 45° rib geometries corresponding to blockage ratios of 0.133, 0.167 and 0.25 were tested in a square channel for pitch-to-height ratios of 5, 8.5 and 10, and for two distinct thermal boundary conditions of heated and unheated channel walls. Comparisons were made between the surface averaged heat transfer coefficients and friction factors for 45° ribs, and 90° ribs reported previously. Heat transfer coefficients of the furthest upstream rib and that of a typical rib located in the middle of the rib-roughened region were also compared. It was concluded that: a) For the geometries tested, the rib average heat transfer coefficient was much higher than that for the area between the ribs. b) Except for two cases corresponding to the highest blockage ribs mounted at pitch-to-height ratios of 8.5 and 10 for which the heat transfer results of 45° ribs were very close to those of 90° ribs, 45° ribs produced higher heat transfer coefficients than 90° ribs. c) At pitch-to-height ratios of 8.5 and 10, all 45° ribs produced lower friction factors than 90° ribs. However, when they were brought closer to each other (S/e=5), they produced higher friction factors than 90° ribs. d) Heat transfer coefficients for the two smaller rib geometries (e/Dh=0.133 and 0.167) did not vary significantly with the pitch-to-height ratio in the range tested. However, the heat transfer coefficient for the high blockage rib geometry increased significantly as the ribs were brought closer to each other. e) Under otherwise identical conditions, ribs in the furthest upstream position produced lower heat transfer coefficients than those in the midstream position. f) Rib thermal performance decreased with the rib blockage ratio. For both angles of attack, the smallest rib geometry in the midstream position and at a pitch-to-height ratio of 10 had the highest thermal performance, and the highest blockage rib in the furthest upstream position produced the lowest thermal performance.
The Coal-Fired PFBC Machine: Operating Experience and Further Development
Authors: Jansson Sven A. , Veenhuizen Dirk , Pillai Krishna K. , Björklund Jan
Published: January 2015

The key components of Pressurized Fluidized Bed Combined Cycle (PFBC) plants are the specially designed gas turbine, which we refer to as the PFBC machine, and the pressurized fluidized bed boiler used to generate and superheat steam for expansion in a steam turbine, in ABB’s P200 and P800 modules, ABB Stal’s 17 MWe GT35P and 70 MWe GT140P machines, respectively, are used. Particulate cleanup before expansion in the turbine sections is with cyclones.

So far, over 70,000 hours of operation has been accumulated on P200 modules in the world’s first PFBC plants, demonstrating that PFBC meets the expectations. The GT35P machines have been found to perform as expected, although some teething problems have also been experienced. The next P200 plant will be built in Germany for operation on brown coal. The first GT140P machine has been manufactured. After shop testing in Finspong, it will be shipped to Japan for installation in the first P800 plant, which is under construction.

Future development of the PFBC machines are foreseen to include raising the turbine inlet temperature through combustion of a topping fuel in order to reach thermal efficiencies which ultimately may be in the range of 50 to 53% (LHV).
Three-Dimensional Flame Structure in Wall-Fired Swirl Flame Combustors
Authors: Su Ay , Lee Ze-Chern , Ho Wu-Chi
Published: January 2015

A CFD solver CFX is used to analyze the complex behavior of turbulent reacting flow inside the furnace. The flow characteristics for various combustor geometries, fuel/air ratios, and injection velocities, and swirl levels are investigated. Starting with a cylindrical furnace fired with gaseous fuel from a concentric tube burner (both with and without swirl), the mixture-fraction is predicted using the k-ε and RSM turbulence models. The discrepancies between the predictions and measurements are most significant in the flame core of upstream regions. It may stem from inappropriateness of the assumed inlet conditions and the combustion model. However, the calculated results are still qualitatively acceptable. After the validation work of the numerical model, a rectangular furnace with four wall-fired swirling combustors is employed to investigate the effect of neighbouring burners and geometry on combustion characteristics. The central recirculation zone which appeared in the isothermal flowfield vanished in the combustion case. It may be attributed to the fact that the hot gas suddenly expands outward and destroys the recirculation mechanism. Thus, the central flame could not hold. In addition, the four corner flames are stretching against the wall and their shapes are similar to a “cam” profile. The results are intended to assist in the development and validation of a numerical model for predicting furnace flows in wall-fired power plants.
Numerical Studies on Trapped-Vortex Concepts for Stable Combustion
Authors: Katta Viswanath R. , Roquemore W. M.
Published: January 2015

Spatially locked vortices in the cavities of a combustor aid in stabilizing the flames. On the other hand, these stationary vortices also restrict the entrainment of the main air into the cavity. For obtaining good performance characteristics in a trapped-vortex combustor, a sufficient amount of fuel and air must be injected directly into the cavity. This paper describes a numerical investigation performed to better understand the entrainment and residence-time characteristics of cavity flows for different cavity and spindle sizes. A third-order-accurate time-dependent Computational Fluid Dynamics with Chemistry (CFDC) code was used for simulating the dynamic flows associated with forebody-spindle-disk geometry. It was found from the non-reacting flow simulations that the drag coefficient decreases with cavity length and that an optimum size exists for achieving a minimum value. These observations support the earlier experimental findings of Little and Whipkey (1979). At the optimum disk location, the vortices inside the cavity and behind the disk are spatially locked. It was also found that for cavity sizes slightly larger than the optimum, even though the vortices are spatially locked, the drag coefficient increases significantly. Entrainment of the main flow was observed to be greater into the smaller-than-optimum cavities. The reacting-flow calculations indicate that the dynamic vortices developed inside the cavity with the injection of fuel and air do not shed, even though the cavity size was determined based on cold-flow conditions.
Heavy-Duty Gas Turbine Plant Aerothermodynamic Simulation Using Simulink
Authors: Crosa G. , Pittaluga F. , Trucco Martinengo A. , Beltrami F. , Torelli A. , Traverso F.
Published: January 2015

This paper presents a physical simulator for predicting the off-design and dynamic behaviour of a single shaft heavy-duty gas turbine plant, suitable for gas-steam combined cycles.

The mathematical model, which is non linear and based on the lumped parameter approach, is described by a set of first-order differential and algebraic equations. The plant components are described adding to their steady state characteristics the dynamic equations of mass, momentum and energy balances. The state variables are mass flow rates, static pressures, static temperatures of the fluid, wall temperatures and shaft rotational speed.

The analysis has been applied to a 65 MW heavy-duty gas turbine plant with two off-board silo-type combustion chambers. To model the compressor, equipped with variable inlet guide vanes, a subdivision into five partial compressors is adopted, in serial arrangement, separated by dynamic blocks. The turbine is described using a one dimensional row by row mathematical model, that takes into account both the air bleed cooling effect and the mass storage among the stages. The simulation model considers also the air bleed transformations from the compressor down to the turbine.

Both combustion chambers have been modelled utilising a sequence of several sub-volumes, to simulate primary and secondary zones in presence of three hybrid burners.

A code has been created in Simulink environment. Some dynamic responses of the simulated plant, equipped with a proportional-integral speed regulator, are presented.
Combustion System Development for Dry Low-NOx Emission and High Turbine Inlet Temperatures
Authors: Becker Bernard , Schulten Wilhelm , Schetter Bernhard
Published: January 2015

The last 10 years of combustor development are characterised by the introduction of lean premixed burners for dry low-NOx emissions. This was easy to achieve as long as sufficient excess air was available. The modern gas turbine with its high turbine inlet temperature and increased need for component cooling sees a competition for air between combustion and requirements in other areas.

The paper describes how these problems have been solved by changing the design of burners and combustion chambers. The goal of minimising the hot surface area for a given combustor volume is achieved with the annular combustors. The number of burners has been selected in order to achieve good cross ignition, uniform temperature distribution and reasonably short residence times with the minimum of components. Test results and experience with operation and maintenance are also reported.
Experimental and Numerical 3-D Investigations of the Flow Field Behind the Trailing Edge of a Cooled Turbine Guide Vane
Authors: Bohn Dieter E. , Becker Volker J. , Behnke Klaus D.
Published: January 2015

Experimental investigations have been carried out to analyze the hot gas flow and cooling gas flow in the direct vicinity of the trailing edge of a modern gas turbine vane, with cooling gas ejection through the trailing edge. The investigations were performed in one of the institute’s test turbines. The experimental set-up is designed to establish variable blowing ratios between cooling gas mass flow and hot gas mass flow. An alternative density ratio between hot gas and cooling gas was established by the use of CO2 instead of air as the cooling gas for cold test runs. The experimental investigations have been carried out for different radial positions. The measurement plane was located 0.2mm to 0.5mm downstream of the trailing edge (trailing edge width 1.6mm).

Local regions of high anisotropic turbulence were detected in the mixing zone. For low blowing ratios, the trailing edge pressure side in the tip vicinity was found to be subjected to direct hot gas contact. The trailing edge ejection has an influence of at least one chordlength in axial direction.

The experimental investigations were accompanied by 3-D Navier-Stokes computational simulations. The calculated velocity distributions were found to be quite consistent with the experimental results. The calculated flow angles differed locally from the measurements. This may be due to the turbulence model employed.
Crack Detection, Localization and Estimation of the Intensity in a Turbo Rotor
Authors: Park R.-W.
Published: January 2015

The goal of this paper is to describe an advanced method of a crack detection, a new way to localize the crack position and to estimate the intensity of the depth with reference to a rotating shaft. As a first step, the shaft is physically modelled with a finite element method as usual and the dynamic mathematical model is derived from it using the Hamilton-principle and in this way the system is modelled by various subsystems. The equations of motion with crack is established by adaption of the local stiffness change through breathing and gaping from the crack to the equation of motion with undamaged shaft. This is supposed to be regarded as reference for the given system.

Based on the fictitious model of the time behaviour induced from vibration phenomena measured at the bearings, a nonlinear State Observer is designed in order to detect the crack on the shaft. This is elementary NL-observer (EOB). Using the elementary observer, an Estimator (Observer) Bank is established and arranged at the certain position on the shaft. In case a crack is found and its position is known, the procedure for the estimation of the depth is going to begin.
Assessment and Monitoring Requirements for Industrial Gas Turbine Hot Section Components
Authors: Wood M. I. , Cotgrove R. M.
Published: January 2015

Conventional surveillance techniques and the metallurgical assessment of components are discussed as being part of a continuum of monitoring activity. They emphasise respectively operational and maintenance durability considerations. The importance and benefits to be gained from fully utilising both techniques, particularly for the new designs of units, is illustrated by reference to the problems in a recent design of 40 MW heavy duty industrial turbine.
Laser Drilling Effusion Cooling Holes in Low NOx Turbine Engine Components
Authors: VanderWert Terry L. , Litzer Scott A. , Meng Loh Wai
Published: January 2015

The move to turbine engine designs featuring low NOx emissions and greater fuel efficiency has resulted in a major change in design and manufacture of certain engine parts such as combustion chambers. For example, effusion cooling combustor designs use thousands of 0.5 mm diameter, shallow angle (less than 30 degrees from the surface) holes to provide a film of cooling air over the surface of the combustor. A variety of thermal barrier coatings are also used to protect the surface during operation.

Laser drilling is playing a key role in the production of effusion cooling holes. Laser drilling, which uses the focused output of a high power industrial pulsed Nd:YAG laser to trepan the holes, has become the process of choice for producing these because of:

- low heat input

- rapid drilling rates

- ability to drill ceramic coated metals

- a minimum number of process variables contributes to reliable, repeatable processes

This paper reviews the laser drilling process for producing effusion cooling holes, characteristics of the holes, and developments aimed at increasing the throughput and, therefore, reducing the cost for laser drilling. The paper also summarizes the key aspects of the laser system required to produce combustors that meet airflow and other quality (metallurgical) specifications.
Part Load Conditions of Complex Cycle Power Plants With Intercooled Gas Turbine
Authors: Peretto A.
Published: January 2015

The present paper evaluates the behavior, in design and part load working conditions, of a complex gas turbine cycle with multiple intercooled compression, and the optional preheating of the air at the high pressure compressor outlet by means of the gas turbine outlet hot gas.

The results are then compared with those obtained by a Brayton cycle gas turbine, with or without preheating of the air at the high pressure compressor outlet.

Subsequently, the performance of complex combined cycles, with intercooled gas turbine as topper and one, two or three pressure level steam cycle as bottomer, in design and part load working conditions is also evaluated.

The performance of these complex combined plants is then compared with that obtained by a Brayton cycle gas turbine as topper and one, two or three pressure level steam cycle as bottomer.

Part load working conditions are realized by varying either the inlet guide vane angle of the first compressor nozzles or the maximum temperature at the combustor outlet.

The study shows that in part load working conditions obtained by varying IGV, the complex cycles, in the examined gas turbine or in the combined cycle power plants, give conversion efficiencies decidedly greater than those obtainable by varying combustor exit temperature.

Furthermore it is found that these complex power plant efficiencies, in part load working conditions, are far greater than those obtained by the Brayton cycle gas turbine, or by combined cycle with Brayton cycle gas turbine as topper, if IGV adjustment is adopted.

If power variation is obtained with combustor outlet temperature adjustment, the efficiencies of the combined power plants with complex or Brayton cycle gas turbines, are substantially the same, for the same relative power variation.
The Application of Gas Turbines in Industrial Combined Heat and Power: An Operational Strategy for Maximising Profit
Authors: Iqbal Anees , Fenemore Keith
Published: January 2015

The concept of industrial combined heat and power (CHP) systems has been put into practice for most of this century. Prior to the 1960’s, however, the chemical, petrochemical, iron and steel and paper industries normally installed CHP systems based on steam turbines. The oil crisis of 1973 brought an end of the era of secure low fuel prices. This crisis prompted successful moves towards improving energy conservation, mainly in thermal efficiency. The heat to power ratio was reduced in most industries, making the steam turbine system alone less attractive. Consequently gas turbines have frequently taken over as the basic prime mover for CHP systems, though associated with steam turbines in appropriate situations.
Combustion Within Gas Turbines: The Laval University Approach
Authors: Kretschmer D. , Odgers J. , DeChamplain A.
Published: January 2015

A pragmatic approach is a major feature of the training of combustion engineers at Laval. An introduction is given in a second year thermodynamic course and (optionally) this is enhanced by a theoretical course and a design course. At the graduate level advanced theory is studied, together with a ‘hands-on’ experiment. Theses subjects are available at both Masters and Doctorate levels.
Behaviour of a HRSG Steam System During Flying Switch-Over to Fresh Air Operation After Gas Turbine Trip
Authors: Linnemeijer M. J. J.
Published: January 2015

The reliability and availability of a HRSG steam system can be improved by providing a flying switch over into fresh air operation in case of failure of the gas turbine.

The flying switch over can be designed for a planned switch over in case of no availability of the gas turbine as well for a unplanned switch over in case of gas turbine trip.

Especially during the unplanned switch over the pressure of the steam system will decrease due to a temporarily lack of heat input on the HRSG.

The paper will describe different switch over arrangements and their influences on the pressure of the steam system during the switch over.
Shedding of the tumor necrosis factor (TNF) receptor from the surface of hepatocytes during sepsis limits inflammation through cGMP signaling
Authors: Deng Meihong , Loughran Patricia A. , Zhang Liyong , Scott Melanie J. , Billiar Timothy R.
Published: January 2015

Drugs used to treat erectile dysfunction may be repurposed to inhibit inflammation and treat patients with sepsis.
Venom induces insulin shock
Authors: VanHook Annalisa M.
Published: January 2015

Predatory snails use weaponized insulin to disable vertebrate prey.
Turned off by chloride
Authors: Gough Nancy R.
Published: January 2015

Na
+
/HCO
3
-
transporters are inhibited by intracellular Cl
-
.
Synergistic Suppression of Dengue Virus Replication Using a Combination of Nucleoside Analogs and Nucleoside Synthesis Inhibitors
Authors: Yeo Kim Long , Chen Yen-Liang , Xu Hao Ying , Dong Hongping , Wang Qing-Yin , Yokokawa Fumiaki , Shi Pei-Yong
Published: January 2015

Dengue virus (DENV) is the most prevalent mosquito-borne viral pathogen in humans. Currently, there is no clinically approved vaccine or antiviral for DENV. Combination therapy is a common practice in antiviral treatment and a potential approach to search for new treatments for infectious pathogens. In this study, we performed a combination treatment in cell culture by using three distinct classes of inhibitors, including ribavirin (a guanosine analog with several antiviral mechanisms), brequinar (a pyrimidine biosynthesis inhibitor), and INX-08189 (a guanosine analog). The compound pairs were evaluated for antiviral activity by use of a DENV-2 luciferase replicon assay. Our result indicated that the combination of ribavirin and INX-08189 exhibited strong antiviral synergy. This result suggests that synergy can be achieved with compound pairs in which one compound suppresses the synthesis of the nucleoside for which the other compound is a corresponding nucleoside analog. In addition, we found that treatment of cells with brequinar alone could activate interferon-stimulated response elements (ISREs); furthermore, brequinar and NITD-982 (another pyrimidine biosynthesis inhibitor) potentiated interferon-induced ISRE activation. Compared to treatment with brequinar, treatment of cells with ribavirin alone could also induce ISRE activation, but to a lesser extent; however, when cells were cotreated with ribavirin and beta interferon, ribavirin did not augment the interferon-induced ISRE activation.
Characterization of Mouse Models of Mycobacterium avium Complex Infection and Evaluation of Drug Combinations
Authors: Andréjak Claire , Almeida Deepak V. , Tyagi Sandeep , Converse Paul J. , Ammerman Nicole C. , Grosset Jacques H.
Published: January 2015

The
Mycobacterium avium
complex is the most common cause of nontuberculous mycobacterial lung disease worldwide; yet, an optimal treatment regimen for
M. avium
complex infection has not been established. Clarithromycin is accepted as the cornerstone drug for treatment of
M. avium
lung disease; however, good model systems, especially animal models, are needed to evaluate the most effective companion drugs. We performed a series of experiments to evaluate and use different mouse models (comparing BALB/c, C57BL/6, nude, and beige mice) of
M. avium
infection and to assess the anti-
M. avium
activity of single and combination drug regimens,
in vitro
,
ex vivo
, and in mice.
In vitro
, clarithromycin and moxifloxacin were most active against
M. avium
, and no antagonism was observed between these two drugs. Nude mice were more susceptible to
M. avium
infection than the other mouse strains tested, but the impact of treatment was most clearly seen in
M. avium
-infected BALB/c mice. The combination of clarithromycin-ethambutol-rifampin was more effective in all infected mice than moxifloxacin-ethambutol-rifampin; the addition of moxifloxacin to the clarithromycin-containing regimen did not increase treatment efficacy. Clarithromycin-containing regimens are the most effective for
M. avium
infection; substitution of moxifloxacin for clarithromycin had a negative impact on treatment efficacy.
Eravacycline (TP-434) Is Active
In Vitro
against Biofilms Formed by Uropathogenic Escherichia coli
Authors: Grossman Trudy H. , O'Brien William , Kerstein Kathryn O. , Sutcliffe Joyce A.
Published: January 2015

Eravacycline (formerly TP-434) was evaluated
in vitro
against pre-established biofilms formed by a uropathogenic
Escherichia coli
strain. Biofilms were eradicated by 0.5 μg/ml eravacycline, which was within 2-fold of the MIC for planktonic cells. In contrast, colistin and meropenem disrupted biofilms at 32 and 2 μg/ml, respectively, concentrations well above their respective MICs of 0.5 and 0.03 μg/ml. Gentamicin and levofloxacin eradicated biofilms at concentrations within 2-fold of their MICs.
Novel Aggregative Adherence Fimbria Variant of Enteroaggregative Escherichia coli
Authors: Jønsson Rie , Struve Carsten , Boisen Nadia , Mateiu Ramona Valentina , Santiago Araceli E. , Jenssen Håvard , Nataro James P. , Krogfelt Karen A.
Published: January 2015

Enteroaggregative
Escherichia coli
(EAEC) organisms belong to a diarrheagenic pathotype known to cause diarrhea and can be characterized by distinct aggregative adherence (AA) in a stacked-brick pattern to cultured epithelial cells. In this study, we investigated 118 EAEC strains isolated from the stools of Danish adults with traveler's diarrhea. We evaluated the presence of the aggregative adherence fimbriae (AAFs) by a multiplex PCR, targeting the four known major subunit variants as well as their usher-encoding genes. Almost one-half (49/118) of the clinical isolates did not possess any known AAF major fimbrial subunit, despite the presence of other AggR-related loci. Further investigation revealed the presence of an AAF-related gene encoding a yet-uncharacterized adhesin, termed
agg5A
. The sequence of the
agg5DCBA
gene cluster shared fimbrial accessory genes (usher, chaperone, and minor pilin subunit genes) with AAF/III, as well as the signal peptide present in the beginning of the
agg3A
gene. The complete
agg5DCBA
gene cluster from a clinical isolate, EAEC strain C338-14, with the typical stacked-brick binding pattern was cloned, and deletion of the cluster was performed. Transformation to a nonadherent
E. coli
HB101 and complementation of the nonadherent C338-14 mutant with the complete gene cluster restored the AA adhesion. Overall, we found the
agg5A
gene in 12% of the 118 strains isolated from Denmark, suggesting that this novel adhesin represents an important variant.
The Proprotein Convertase Subtilisin/Kexin FurinA Regulates Zebrafish Host Response against Mycobacterium marinum
Authors: Ojanen Markus J. T. , Turpeinen Hannu , Cordova Zuzet M. , Hammarén Milka M. , Harjula Sanna-Kaisa E. , Parikka Mataleena , Rämet Mika , Pesu Marko
Published: January 2015

Tuberculosis is a chronic bacterial disease with a complex pathogenesis. An effective immunity against
Mycobacterium tuberculosis
requires both the innate and adaptive immune responses, including proper T helper (Th) type 1 cell function. FURIN is a proprotein convertase subtilisin/kexin (PCSK) enzyme, which is highly expressed in Th1 type cells.
FURIN
expression in T cells is essential for maintaining peripheral immune tolerance, but its role in the innate immunity and infections has remained elusive. Here, we utilized
Mycobacterium marinum
infection models in zebrafish (
Danio rerio
) to investigate how
furin
regulates host responses against mycobacteria. In steady-state
furinA
td204e/+
fish reduced
furinA
mRNA levels associated with low granulocyte counts and elevated Th cell transcription factor expressions. Silencing
furin
genes reduced the survival of
M. marinum
-infected zebrafish embryos. A mycobacterial infection upregulated
furinA
in adult zebrafish, and infected
furinA
td204e/+
mutants exhibited a proinflammatory phenotype characterized by elevated
tumor necrosis factor a
(
tnfa
),
lymphotoxin alpha
(
lta
) and
interleukin 17a/f3
(
il17a/f3
) expression levels. The enhanced innate immune response in the
furinA
td204e/+
mutants correlated with a significantly decreased bacterial burden in a chronic
M. marinum
infection model. Our data show that upregulated
furinA
expression can serve as a marker for mycobacterial disease, since it inhibits early host responses and consequently promotes bacterial growth in a chronic infection.
Status epilepticus developing during lacosamide monotherapy
Authors: Papacostas Savvas S
Published: January 2015

Two cases with partial onset epilepsy who developed status epilepticus (SE) on lacosamide (LCM) monotherapy are reported. LCM is an effective adjunctive antiepileptic drug (AED) for partial-onset epilepsy and as infusion in SE. It has also shown efficacy in monotherapy. The reported cases achieved control of seizures with adjunctive LCM treatment and were afterwards converted to monotherapy. Both patients subsequently developed SE while on LCM monotherapy. They were on monotherapy for at least 2 months after withdrawal of concomitant AEDs precluding the possibility of withdrawal-induced SE. Pharmacovigilance is indicated when LCM is administered in monotherapy in order to assess its proper therapeutic potential and its putative limitations especially in cases where it may prove ineffective. Moreover, vigilance is necessary whenever any concomitant antiepileptic is tapered regardless of the substances used. Higher doses may be needed when an AED is used in monotherapy.
Cholesterol-lowering properties of oat β-glucan and the promotion of cardiovascular health: did Health Canada make the right call?
Authors: Nwachukwu Ifeanyi D. , Devassy Jessay G. , Aluko Rotimi E. , Jones Peter J.H.
Published: January 2015

In 2010, Health Canada approved a heath claim acknowledging the link between increased oats (Avena sativa)-soluble fibre consumption and a reduction in total serum cholesterol levels. The approval also recognized the relationship between decreased total blood cholesterol concentration and a reduced risk of coronary heart disease. The functional food ingredient believed to be responsible for the hypocholesterolemic property of oats is β-glucan, a highly viscous, soluble fibre composed of d-glucose monomers linked by a combination of β-(1→4) and β-(1→3) glycosidic bonds. Found mainly in the endosperm cell wall of oats, β-glucan is thought to reduce total serum and low-density lipoprotein cholesterol by forming a viscous mass in the small intestine thus limiting intestinal absorption of dietary cholesterol as well as the re-absorption of bile acids. Given the evolution of research information with time as a result of the continual, rapid generation of new research data by laboratories around the world, it became imperative to examine the compatibility of the conclusion reached by Health Canada on the basis of the body of evidence contained in the initial petition submitted in January 2007, with newer post-2006 data. After careful evaluation, this work concludes on the basis of new research information that a dose of 3 g/day oat β-glucan consumed as part of a diet “free of saturated fatty acids” or “low in saturated fatty acids” could help to promote cardiovascular health.
Hydrocarbon resources potential mapping using evidential belief functions and frequency ratio approaches, southeastern Saskatchewan, Canada
Authors: Arab Amiri Mohammad , Karimi Mohammad , Alimohammadi Sarab Abbas
Published: January 2015

The purpose of the present study is to model the hydrocarbon resources potential mapping using geographic information systems (GIS). The presented method is based on petroleum system concepts; therefore, petroleum system elements were used to define criteria for petroleum potential mapping. Several statistical methods can be used to effectively predict potential areas for hydrocarbon resources. In this study, two statistical methods were used (frequency ratio and evidential belief functions) to predict the potential distribution of petroleum resources in the study area. A case study in the Red River – Red River petroleum system of the Canadian Williston Basin in southeastern Saskatchewan in Canada is proposed to assess the feasibility of this new modelling technique. The accuracy of the hydrocarbon potential maps was evaluated by success rate and prediction rate efficiency curves. The resultant petroleum potential maps resulted in delineation of high-potential zones occupying about 15% of the study area. The validation results showed that the prediction rate for the best model is 88.14%. This study was carried out at a regional scale; therefore, the results can be used to guide exploration works at early stages.
A three-dimensional skull ontogeny in the bobcat (Lynx rufus) (Carnivora: Felidae): a comparison with other carnivores
Authors: Segura Valentina
Published: January 2015

The maturation of mammalian carnivores from a lactating juvenile to a predatory adult requires a suite of changes in both morphology and behaviour. Bobcats (Lynx rufus (Schreber, 1777)) are medium-sized cats with well-developed skulls to process large prey that can exceed their body mass. An integrated view of the skull ontogeny in the bobcat was developed to detect the relationship between shape, size (on the basis of three-dimensional geometric morphometric analysis), and life history. Dietary changes from juvenile to adults were taken into account and compared with other carnivores. Newborns were different from the remaining age stages in the behavioral and morphological characters examined, which allows us to relate them to the terminal morphology reached during the prenatal period. All findings were related to the reinforcement of the skull and the enhancement of predatory skills in adult bobcats. The final cranial shape is reached in A2 age class, after 2 years of age, and once sexual maturity has been reached. This is a pattern not followed for the rest of carnivores previously studied, which might be related to the capacity of subduing prey that exceed them in size, a behavior not common in felids of the body size of bobcats.
THE EFFECT OF STRESS TOLERANCE ON DYNAMICS OF ACTIVITY–TRAVEL BEHAVIOR: NUMERICAL SIMULATION RESULTS
Authors: PSARRA IFIGENIA , ARENTZE THEO , TIMMERMANS HARRY
Published: January 2015

The primary and secondary effects of various spatial and transportation policies can be evaluated with models of activity–travel behavior. Whereas existing activity-based models of travel demand simulate a typical day, dynamic models simulate behavioral response to endogenous or exogenous change, along various time horizons. The current study aims at developing a model of endogenous dynamics of activity–travel behavior. Endogenous dynamics are induced by stress, which is regarded as dissatisfaction with current habits. It is assumed that people try to alleviate stress by trying short-term changes, within the options known to them or by exploring new options. If these explorations prove to be unsuccessful, they will consider long-term changes, such as moving to a new residential location, buying a car, etc. Therefore, this self-improvement process can result in both short and long-term adaptations. In the proposed framework, choice-set formation is modeled, the key concepts of aspiration, activation, awareness and expected utility are integrated, while both rational and emotional mechanisms are taken into account. Numerical simulations are conducted in order to check the face validity of the model, as well as the impact of stress tolerance parameters on system performance.