bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Overall Review: Modified Asphalt Binder Containing Sasobit in Warm-Mix Asphalt Technology
Authors: Hainin Mohd. Rosli , A. Aziz Md. Maniruzzaman , Feizabadi Shahab Moeini , Putra Jaya Ramadhansyah , Abdul Hassan Norhidayah , Mohd Jakarni Fauzan 
Published: April 2015

Increasing emission of greenhouse gases is an environmental issue, and it is a great concern to curb this problem from further harm to the environment. Warm-mix asphalt (WMA) is one of efforts to curb a reduction in the temperature at which asphalt mixes are produced. WMA can reduce the temperature to 100°C and even lower without compromising the performance of asphalt binder. WMA has various benefits such as, reduction of asphalt binder temperature, reduction in energy consumption and less air pollution. It reduces short-term aging, compacting effort and decreases temperature drop during transportation. Sasobit is one of the organic additives of warm mix asphalt. It is used as a binder modifier to produce rut resistant mixtures. It provides the option of reducing fume emissions, saving energy and reducing production cycles. Therefore, sasobit is the preferred additive for warm-mix asphalt (WMA). In addition, Complex shear modulus will be determined to find the rutting factor and fatigue factor for the asphalt binder (G*/Sinδ and G*Sinδ respectively). The overall purposes of this study are to determine the importance of using WMA as a green pavement and introducing sasobit for modifying virgin asphalt binder.
Evaluation of Warm Mix Asphalt Performance with High RAP Content
Authors: Arshad Ahmad Kamil , Ma Kridan Frag Ahmed , Kamaluddin Noor Azreena , Shafie Ekarizan 
Published: April 2015

The pavement industry is currently forced to find alternative ways to produce asphaltic concrete with the dwindling supply of new resources and the spiraling cost of materials. Warm Mix Asphalt (WMA) using reclaimed asphalt pavement (RAP) offers a sustainable solution to the problem by reducing energy requirements for production and the reuse of old pavement materials. The effects of warm mix asphalt additive (Sasobit) on mixes containing different percentages of RAP were investigated in the laboratory. Three different concentrations of RAP (30%, 40% and 50%) with 1.5% Sasobit by weight of binder were added, and Marshall method was used to produce all samples investigated. Two different mixing and compaction temperatures were used, 155°C and 135°C for mixing and 135°C and 120°C for compaction. The performance of the mixes in terms of stiffness and moisture damage were investigated by carrying out the Indirect Tensile Resilient Modulus Test (ASTM D4123) and moisture susceptibility test (ASTM D 4867). The results obtained showed that there were no substantial differences in volumetric properties, stability and stiffness values of reclaimed mixes than the control mix (conventional hot mix asphalt). In addition, all the mixes investigated achieved the required minimum TSR of 80%. Measured rut depth using the Asphalt Pavement Analyser (APA) device and fatigue cycles to failure using beam specimen indicated that the mixes performed similar to or better than the control mix. The results showed that warm mix asphalt using sasobit-additive and containing high percentages of RAP could be a sustainable alternative to the conventional HMA mix.
Control Aspects of a Compressor Station for Gas Lift
Authors: Saadawi H. 
Published: April 2015

The type and characteristics of the control system to be used for a centrifugal compressor station depend on several factors such as the compressor driver, process requirements, and the conditions under which the compressor will be operated. Designing a compressor control system for gas lift applications present different types of problems than those of conventional pipeline applications.
This paper describes the control philosophy of a compressor station used for lifting water in a closed-rotative gas lift installation in Bu Hasa field, Abu Dhabi.
Post-Test Evaluation of a Prototype Composite Water-Cooled Gas Turbine Nozzle
Authors: Muth M. C. , Beltran A. M. 
Published: April 2015

Water-cooled high temperature gas turbine technology has been under investigation by the Gas Turbine Division of the General Electric Company for the past 15 years. The transition from testing small scale laboratory-size hardware to full-scale gas turbine components was initiated in 1975 by General Electric and extended further under the U.S. Department of Energy’s High Temperature Turbine Technology (HTTT) Program. A key element in this transition was the identification of a composite (hybrid) design for the first-stage nozzles. This design permits efficient heat transfer to the water-cooling passage-ways, thus lowering effective strains and increasing part life. The results of GE’s extensive efforts over many years to develop a composite water-cooled first-stage nozzle were further confirmed through the successful fabrication and testing of full-scale hardware under the DOE/HTTT Program.
This paper describes the post test metallurgical evaluation of two segments of the nozzle tested under the DOE/HTTT program. A brief description of the actual hot-gas path testing of the part is given. The bulk of the paper deals with a microstructural evaluation of the segments including microprobe traces and hardness surveys. Pre- and post-test non-destructive evaluations are also reviewed.
Development of a Low Btu Gas Fuel Cooled Combustor for 3000°F Gas Turbine Operation
Authors: Koblish T. R. , Schaefer R. 
Published: April 2015

The attraction of a coal gasification combined cycle system to utility operation lies in its higher efficiencies (pile-to-busbar) relative to competing power generating systems. In order to achieve these higher efficiencies the coal gasification combined cycle combustor/turbine section must provide reliable operation with low or medium Btu gaseous coal derived fuel at turbine inlet temperature levels above 2600°F.
Utilization of low Btu gas (LBG) fuel for attainment of temperature levels up to 3000°F in a gas turbine combustor environment presents several unique design and development problems. Because of the extremely high stoichiometric ratios required to attain 3000°F, the management of combustor cooling as well as internal air and low Btu gas fuel flow mixing patterns is considered critical for high combustion efficiency and stability. Equally important is the requirement for long term combustor durability. A unique combustor design concept has been developed to utilize the available heat sink capability of the LBG fuel to adequately cool the combustor walls for long service life.
Under a U.S. Department of Energy contract, an LBG fuel cooled combustor was designed for operation with 150 Btu/SCF fuel for use in development of a turbine capable of operating at 3000°F. This paper describes the background combustor technology and test program results with 150 Btu/SCF fuel regarding the combustion stability, efficiency, emissions and burner wall temperature levels for operation up to 3000°F exit gas temperatures and 6 atmospheres.
A Simple One-Dimensional Model for Primary Turbine Blade Erosion Prediction
Authors: Dussourd J. L. 
Published: April 2015

Sophisticated models to predict the erosion process in turbine blades exposed to dust laden gas stream quickly become complex and tedious for use for everyday engineering applications. A simpler model for primary erosion can be formulated by assimilating the blade row to a device having a certain size and deflecting the stream through a given angle and at a given rate. The technology which exists for particle impacts physics with bluff bodies can be adapted to cascades. Thus, basically the model is derived from first principles.
This approach is formulated in a quantitative manner in terms of cascade parameters, gas properties, and particulate parameters. The result is a simple equation which is easy to use and the physics of which are logical and intuitively reasonable. Its predictive ability, however, is limited to the frequency of impacts and the strength of the impacts. It does not address the mechanics of the impact process or the properties of the material being impacted. These variables are introduced through an experimental coefficient which, as it turns out, is the only experimental input in the analysis.
The method is tested against quite a few experimental cases with a degree of predictive ability which is acceptable in a simple, first order method. The agreement is thought to be at least as good as the credibility or accuracy of the test data. The method is finally applied to study the effects of various blade cascade parameters on erosion resistance, the results of which are presented in the form of general curves.
Danish Navy Experience With the KV-72 LM2500 CODOG Propulsion Plant
Authors: Hansen Bent , Larsen Sloth , Tenhundfeld John W. 
Published: April 2015

For more than twenty years the Royal Danish Navy (RDN) has been using gas turbine engines for propulsion of fast patrol vessels as well as frigates. This paper, which is the result of a joint effort by the Royal Danish Navy, Aalborg Vaerft Shipyard, and General Electric Company USA, describes how the propulsion system design was developed using previous RDN gas turbine system experience. A detailed description of the ship, the selection of machinery, and design of the propulsion configuration, including the LM2500 gas turbine module, is included.
The three Royal Danish “KV-72” corvettes of the NIELS JUEL class have now been in operation for almost three years. Since the start-up of the NIELS JUEL machinery in November 1978 the CODOG propulsion plants aboard this class have accumulated more than 8,000 running hours, of which over 1,500 hours have been in the gas turbine or “sprint” drive mode. Operational experience with the GE LM2500 gas turbines is also described.
In Situ Balancing of Flexible Rotors Using Influence Coefficient Balancing and the Unified Balancing Approach
Authors: Darlow Mark S. 
Published: April 2015

A number of sophisticated procedures for balancing flexible rotors have been developed during the past two decades. For a variety of reasons, none of these methods has gained general acceptance by practicing balancing engineers. Several of these balancing techniques require a great deal of operator insight and expertise. This has tended to discourage many potential users where this expertise was not already available in-house, particularly where balancing is required as a production operation. In other cases (for example large steam turbines), the machinery owner has had to rely on the manufacturer to provide this balancing expertise when it is needed often resulting in excessive downtime and maintenance costs.
Other balancing methods have been developed which are more systematic so as to reduce the level of expertise required of the user. Unfortunately, these methods have invariably required the collection of large quantities of data and very complex computations. Thus, originally, this data was taken by hand and transcribed for input to a large computer. The results of the balancing calculations were returned some time later for use by the balancing engineer. Such an operation was clearly not conducive to effective commercial application. With the development of minicomputers, the situation was alleviated to a certain extent through the use of more accessible, and even on-line computers to perform these calculations. However even with these minicomputers, in-place flexible rotor balancing facilities were expensive and inconvenient to assemble, and in situ balancing of flexible rotors was impractical if not impossible.
The subsequent development of the microcomputer has made in situ balancing of flexible rotors a possibility. This paper describes a completely portable, microcomputer-based flexible rotor balancing system that uses influence coefficient balancing and the Unified Balancing Approach two of the systematic methods which have been shown to be very effective for balancing flexible rotors. The results of a series of verification tests are also presented.
The Impact of Computers on the Test Cell of Tomorrow
Authors: Ash Clifford F. 
Published: April 2015

Rapidly increasing fuel costs, the increasing complexity of the new engines now available, along with the inaccuracies, inefficiencies and long test cycles inherent in manual testing push the cost of engine testing to unnecessary levels. One promising avenue of relief is the automation of gas turbine testing through the use of real-time computer data acquisition and processing systems.
Remarkable progress has been made in the area of closed-loop or fully automatic operation of the test process from start-up using various programmable steps, recording results as dictated by the test procedure, controlling operation and a safe engine shut down. This paper discusses the successful application of a real-time computer system with both closed and open-loop capabilities. This particular system called “ADAPS™” (Automatic Data Acquisition and Processing System) handled its first 3,000 hours of engine operation without a single hardware or software interruption. Savings in manpower alone in that period was nearly 18,000 man-hours.
Development of a High Temperature Closed Cycle for Energy Saving in LNG Terminals
Authors: Bellofatto Oreste , Galli Augusto , Casmirri Carlo 
Published: April 2015

Several systems for cold energy saving in LNG regasification terminals through electric energy production have been studied and developed up to now based on closed cycles.
This paper schematically compares the main features of a nitrogen high temperature closed cycle with those of a Rankine cycle.
The actual technical possibility of achieving modular plants for 2×109 Nm3/y gasified LNG and for 61 MWh/h electric production with a 993 K max. temperature nitrogen closed cycle is examined.
The Authors illustrate the efficiency trend versus temperature and report the future development of the above cycle with temperatures up to 1093 K.
A Design Study of a Reaction Control System for a V/STOL Fighter/Attack Aircraft
Authors: Beard B. B. , Foley W. H. 
Published: April 2015

For all V/STOL aircraft, some type of attitude control is required in the hovering mode. In the past, this requirement has usually been met with a Reaction Control System (RCS) — a so-called “Puffer-Pipe” system which consists of high pressure gas ducted about the airframe and exhausted through nozzles at the wing tips, nose and tail.
This paper discusses a preliminary design study of an RCS for a STOVL aircraft conceptual configuration presently being developed by General Dynamics’ Fort Worth Division. The study highlights critical limitations and considerations relevant to the choice of an RCS concept. Physical requirements for RCS performance are detailed. Basic physical tradeoffs are elucidated. Various RCS candidate concepts are presented, and judged for their respective merits and drawbacks. The candidate system judged best suited for the particular application proposed is presented and discussed.
Experimental Cascade Analysis of a Transonic Compressor Rotor Blade Section
Authors: Schreiber H. A. , Starken H. 
Published: April 2015

A transonic compressor rotor blade cascade was tested in order to elucidate the flow behaviour in the transonic regime and to determine the performance characteristic in the whole operating range of a rotor blade section. The experiments have been conducted in a transonic cascade wind tunnel, which enables tests even at sonic inlet velocities.
The influence of the upstream Mach number between 0.8 and 1.1 and the inlet flow angle between choking and stalling of the blade row was investigated. The effect of the axial velocity density ratio (AVDR) could be studied by applying an endwall suction device. Furthermore the level of the shock losses was determined from a wake analysis.
A final comparison of cascade losses and those of the corresponding rotor blade element shows good agreement which underlines the applicability of the cascade model in the design of axial flow turbomachines.
Problems Experienced During and After Installation of Gas Compression in UK Southern North Sea
Authors: Simnett A. D. 
Published: April 2015

This paper relates the problems encountered with the operation of series configuration gas compression since its introduction in 1976 to the Leman Gas Field in the UK Southern North Sea gas transmission system.
Various topics are addressed with the problem described and the adopted solution. Although solutions to these problems can be achieved by different methods, it is hoped that by relating these experiences, future operators embarking on offshore compression can take account during design stages and hence dispel the need of expensive modifications to plant offshore.
On the Transient Interaction of Centrifugal Compressors and Their Piping Systems
Authors: Sparks Cecil R. 
Published: April 2015

The problems of surge and other low frequency pulsation phenomena in centrifugal compressor are described in terms of both machine (head curve) characteristics and the flow impedance characteristics of its attached piping. Flow stability criteria are presented in terms of net modal damping, as the combination of piping acoustic damping and equivalent negative damping of the compressor in the surge region of its performance curve. Surge and instability frequencies are related to acoustic reactance of the piping system. Finally, theoretical concepts are verified both by electrical analog models and by field and laboratory data on real compressors.
This paper provides some new and significant findings on the dynamic interaction of centrifugal compressors with piping systems, and describes the basic phenomena underlying these interactions. Good agreement is shown between predicted and measured surge frequencies, and for those termed “piping resonance surge” produced by high flow offsets or flat spots in the head curve.
Entropy Production Rates From Viscous Flow Calculations: Part I — A Turbulent Boundary Layer Flow
Authors: Moore John , Moore Joan G. 
Published: April 2015

A procedure for obtaining entropy production rates from viscous flow calculations is described. The method is based on process thermodynamics; it allows loss production to be calculated in “irreversible equilibrium processes.”
The two-dimensional turbulent boundary layer of Samuel and Joubert is considered. Mean rates of entropy production are evaluated from measured data using rates of dissipation and rates of increase of turbulence kinetic energy. Calculations performed with the Moore Cascade Flow Program give good agreement with mean rates of entropy production and reveal details of the distribution of entropy production throughout the boundary layer. This method is used in Part II to reveal loss sources in calculations for a rectangular elbow.
Entropy Production Rates From Viscous Flow Calculations: Part II — Flow in a Rectangular Elbow
Authors: Moore John , Moore Joan G. 
Published: April 2015

Entropy creation is studied in a three-dimensional turbulent flow in a rectangular elbow with 90 degrees of turning. In Part I, a method of evaluating entropy production rates in calculations of viscous flow was described. This method is used here to show where the calculated losses arise in the flow field.
The flow develops strong passage vortices as large shear layers at the inlet develop a streamwise component of vorticity. The entropy production in the shear layers is compared with the entropy creation in the wall boundary layers. The influence of the three-dimensional flow on the distributions of entropy production in the bend is discussed.
Solution of Particulate Viscous Flow in a Radial Inflow Turbine
Authors: Vittal B. V. R. , Tabakoff W. 
Published: April 2015

The presence of solid particles in turbomachinery flow affects the component performance as well as its life. The subject of particulated flows can be broadly divided into three parts, namely, particle trajectories, the effect of particles on the aerodynamics of flow and material erosion. The first two aspects are investigated in this paper taking into account the viscosity of the carrier fluid.
The Lagrangian formulation is adopted for the particles, whereas the Eulerian approach is used for the continuous phase. The effect of particles is incorporated as interphase force terms in the fully incompressible stream function-vorticity form of the Navier-Stokes equations. The field analysis is based on the numerical integration of this equation over the rotor blade to blade stream channels. The numerical code used to solve the governing equations employs a nonorthogonal boundary fitted coordinate system that suits the most complicated blade geometries. The trajectories of the solid particles are determined including particle impacts with the blades. The particle rebounding velocity and direction after each impact is determined using semi-empirical correlations for the restitution ratios obtained experimentally. The method of analysis is applied to a radial inflow turbine. The effect of particles on the aerodynamics of the flow is studied by analyzing the fluid streamline pattern in the rotor blades with and without solid particles. The analysis is carried out for various particle concentrations.
Validity of a Trunk-Mounted Accelerometer to Measure Physical Collisions in Contact Sports
Authors: Wundersitz Daniel W.T. , Gastin Paul B. , Robertson Samuel J. , Netto Kevin J. 
Published: April 2015

Context:
Accelerometer peak impact accelerations are being used to measure player physical demands in contact sports. However, their accuracy to do so has not been ascertained.

Purpose:
To compare peak-impact-acceleration data from an accelerometer contained in a wearable tracking device with a 3-dimensional motion-analysis (MA) system during tackling and bumping.

Methods:
Twenty-five semielite rugby athletes wore a tracking device containing a 100-Hz triaxial accelerometer (MinimaxX S4, Catapult Innovations, Australia). A single retroreflective marker was attached to the device, with its position recorded by a 12-camera MA system during 3 physical-collision tasks (tackle bag, bump pad, and tackle drill; N = 625). The accuracy, effect size, agreement, precision, and relative errors for each comparison were obtained as measures of accelerometer validity.

Results:
Physical-collision peak impact accelerations recorded by the accelerometer overestimated (mean bias 0.60 g) those recorded by the MA system (P < .01). Filtering the raw data at a 20-Hz cutoff improved the accelerometer’s relationship with MA data (mean bias 0.01 g; P > .05). When considering the data in 9 magnitude bands, the strongest relationship with the MA system was found in the 3.0-g or less band, and the precision of the accelerometer tended to reduce as the magnitude of impact acceleration increased. Of the 3 movements performed, the tackle-bag task displayed the greatest validity with MA.

Conclusions:
The findings indicate that the MinimaxX S4 accelerometer can accurately measure physical-collision peak impact accelerations when data are filtered at a 20-Hz cutoff frequency. As a result, accelerometers may be useful to measure physical collisions in contact sports.