bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Experimental Facility Design to Determine Rotordynamic Coefficients due to Tip Clearance Asymmetry in Axial Turbines
Authors: Oh Seung Hyub , Song Seung Jin , Hong Yong Shik 
Published: December 2014

Many liquid rocket engines for space launch vehicles use high performance turbopumps to deliver fuel and oxidizer to the thrust chamber. Such turbopumps have been plagued by rotordynamic instability caused by non-axisymmetric turbine tip clearance. Yet, there is dearth of experimental data on this phenomenon, and reliable damping data are non–existent. This paper describes a new experimental facility designed and built to obtain aerodynamic stiffness and damping forces in an unshrouded turbine with a whirling rotor.
The experimental facility consists of an air supply system, single turbine stage test section, instrumentation, and auxiliary systems. The test turbine is a 1: 1 replica of an unshrouded turbine stage used in an actual turbopump. This impulse turbine has a design flow coefficient of 0.76 and work coefficient of 5.9. To measure aerodynamic stiffness forces, the turbine casing is mounted so that it is eccentric relative to the turbine rotor which is concentric with the turbine shaft. Thus, static turbine tip clearance asymmetry is obtained. To obtain aerodynamic damping forces, the turbine casing is mounted concentric relative to the turbine shaft, and the turbine rotor is mounted eccentric relative to the shaft. Thus, synchronous forward whirling condition, or dynamic turbine lip clearance asymmetry, is simulated. Currently, the mean tip clearance is 2% of the rotor blade span, and the specified eccentricity is 1% of the rotor blade span. This test rig facilitates acquisition of both stiffness and damping rotordynamic forces due to turbine aerodynamics. In contrast, past experiment designs required two separate drives — one for rotation and second for whirling motion — to simulate whirling turbine. Therefore, the new facility offers a comparably inexpensive and reliable alternative testing method.
Instrumentation consists of pilot static probes, thermocouples, and optical encoder (tachometer) to monitor turbine operating conditions. Proximity probes are used to measure tip clearance. Steady pressure data are obtained through a set of static pressure taps on the casing. Dynamic pressure data are obtained through flush-mounted, Kulita unsteady pressure transducers. Finally, steady and dynamic velocity data are acquired via 2–D hot wire probes. Thus, steady and unsteady flow fields in turbines with statically offset rotor and whirling rotor, respectively, can be measured.
Heat and Mass Transfer Characteristics in Consolidated Silica Gel/Water Adsorption–Cooling System
Authors: Yanagi Hideharu , Ino Nobumi 
Published: December 2014

The heat and mass transfer on adsorption beds is decisive for the operational characteristics of adsorption refrigerators. To overcome its heat and mass transfer limitations a consolidated silica gel adsorption heat exchanger has been designed and successfully developed. It was made of composite as 4.3 wt% graphite, 86.4 wt% silica gel and binders, which was pressed into a heat exchanger module and then dried under a temperature of 90°C for 24 hours. With use of this adsorption heat exchanger, we measured an overall heat transfer coefficient of 62.2 W/m2K at the beginning of desorption cycle and 61.5 W/m2K during desorption, respectively. Whereas corresponding values of a granular silica gel bed were 44.8 W/m2K and 25.9 W/m2K, respectively.
This paper presents the operational characteristics of consolidated silica gel adsorption heat exchanger in refrigeration cycles, in addition to its isoster measurements for silica gel-water pair compared to that of the granular heat exchanger.
An Experimental Analysis on Energy Savings of VAV Systems in Hot and Humid Area
Authors: Yang K. H. , Lee S. K. , Yin H. C. , Wang Y. S. , Ting M. M. 
Published: December 2014

Variable Air Volume (VAV) air-conditioning system presents great energy savings potential especially in hot and humid climate and has been recommended in the Building Energy Code of Taiwan since 1996. Simulation results indicated that the annual energy savings of VAV system in typical commercial buildings in Taiwan could be up to 70% of total fan power.
A full-scale experiment has been performed which validated this result successfully, and would be adapted with the PACS index in the second phase of national Building Energy Code in Taiwan.
A Comparative Study of Centrifugal Chiller Performances After CFC Refrigerant Conversion
Authors: Yang K. H. , Lee S. K. , Chiang Y. S. , Chen W. C. , Ting M. M. 
Published: December 2014

Theoretical analysis indicated that, a typical centrifugal chiller could lose over 8% to 10% of its cooling capacity after converting from R-11 into using R-123 refrigerant. In this study, an attempt to recover some of this capacity loss by slightly decreasing its operating speed was analyzed.
A full-scale experiment was performed to change the gear train of a 300 RT centrifugal chillier, which validated that 3%∼6% capacity recovery could be expected. This is a break-through to promote the chiller conversion for wide engineering applications and is discussed in detail in this paper.
Performance Analysis of Combustion Engine Systems With a Packed Column CO2 Separator Using Aqueous Monoethanolamine (MEA) Solution
Authors: Ikame Masaru , Kan Susumu , Hiraoka Katsuhide , Kumakura Takanao 
Published: December 2014

Systems analysis is performed for a diesel engine of the 10,000 kW class with CO2 recovery equipment using aqueous monoethanolamine solution on the basis of a CO2 mass transfer calculation model for a packed column.
The calculation model is based on the film theory, and gives calculation results in good accuracy, being compared with the experiments on CO2 absorption and on CO2 stripping.
The net output power of the engine reduces in order to recover the CO2 in the exhaust gas of the engine, and reduction of the output power depends on the ratio of the gas-to-liquid feed rate ratio of the stripper to that of the absorber. The operating parameters such as the stripping temperature, the highest loading factor, and the MEA concentration of the solution have an influence on the maximum attainable CO2 recovery ratio. The maximum attainable CO2 recovery ratio depends on the allowable level of the output power reduction, and with reduction of 10% of the engine output power, 70% of CO2 in the exhaust gas is recovered.
An Analytical Comparison Between the Performance of a Hot Water Heat Pump With a Non-Azeotropic Refrigerant Mixture and a Pure Refrigerant
Authors: Smit F. J. , Meyer Josua P. 
Published: December 2014

The applications of hot water in the industrial, domestic and mining applications are numerous, and these are only a few of the core areas of use. In these applications fossil fuels and electrical resistance systems are usually used to heat water to temperatures near boiling point. The refrigerant R22, that is currently being used in hot water heat pumps, delivers hot water temperatures from 60 °C to 65 °C. This limits the applications of hot water heat pumps.
This analytical study uses three comparison methods to investigate and compare the potential of a non-azeotropic refrigerant mixture consisting of R22 and R142b. From the results different advantages of non-azeotropic refrigerant mixtures are evident. Depending on the application, if the results of a non-azeotropic refrigerant mixture are compared with a pure R22 heat pump, an increase in hot water temperatures to above boiling point, an increase in coefficient of performance, an increase in capacity and a decrease in compressor pressure ratio are possible. Unfortunately, not all these advantages are valid for each application. For instance, extremely high hot water temperatures are obtained, whilst the heating capacity is excessively low.
Coal-Fired Magnetohydrodynamic Power Plant With Zero-CO2 Atmospheric Emission
Authors: Iantovski E. , Lhomme R. , Mathieu Ph. 
Published: December 2014

In this system, an MHD generator is used instead of a gas turbine. The cycle efficiency is reaching 50%. The system is based on a cycle using CO2 as the working fluid and oxygen as oxidant. The fuel is pulverized coal. All the pollutants, including the CO2 produced in the combustion process, are fully removed and diposed of. This highly pressurized excess CO2 is easily separated from the working fluid without any costly and energy consuming device and, being in liquid state, is ready for transportation and disposal or possibly reuse in other applications.
The most important parameter determining the cycle efficiency is shown to be the isentropic effectiveness of the MHD expander. This latter is depending, on the one hand, on the design of the channel and on the other hand, on the conductivity of the gases which can be optimized with respect to the cycle parameters.
In conclusion, the assets of the proposed system are high performance and no pollutant releases. As a consequence, MHD generators may be considered as viable options for coal-firing and possible competitors of advanced coal-based plants. One of the spin-off of this study is the possible revival of existing MHD facilities.
Simulation of Mechanical and Thermodynamic Performances of a Ship Propulsion Plant in Transient Conditions
Authors: Carrera Giovanni , Rizzuto Enrico 
Published: December 2014

The paper presents a numerical procedure for the simulation of a marine propulsion plant in transient conditions: the model describes in detail the various elements of the propulsion system and the interactions existing between each of them.
The thermodynamic behaviour of the main engine as well as of the turbocharger group is modelled, in order to predict not only the mechanical stress of the plant due to the transient conditions, but also the thermal stresses and working point of the compressor and of the turbine (pressure and temperature at inlet/outlet).
As a first application of the model, the case is considered of a twin screw vessel powered by two four stroke medium speed diesel engines with controllable pitch propellers. The simulations presented in the paper regard two transient manoeuvres of the ship: slam-start (from zero speed to full ahead) and crash stop (from full ahead to zero speed with a “full astern” command).
The results of the simulations are compared with the available experimental data, regarding the time histories of the vessel speed, space run before a complete stop, propeller r.p.m. and shaft power, showing a good accordance.
The procedure can be utilised to check the behaviour of the turbocharger group during a transient manoeuvre and to identity possible improvements in the ship control system or in the pitch-r.p.m. combination law to optimise the performances, in term of e.g. stopping space of the vessel or thermal and mechanical stresses of the plant.
Application of the GT35 Industrial Gas Turbine for the Propulsion of Fast Ferries
Authors: Svensson Bo S. 
Published: December 2014

The paper describes the modifications required to make the GT35 industrial gas turbine suitable for use in fast ferries as propulsion machinery. The modifications made to get the unit to meet pitch and roll requirements are dealt with, as well as the engine support system modifications.
The GT35’s capability to burn low quality, liquid fuels is discussed, and a close look is taken at the effect such fuel has on the life of the unit and the time between service.
In order to facilitate power production on the ship, the GT35 has been equipped with a starting motor which during operation is used as a shaft driven generator. The generator is driven by the low pressure rotor. Each generator can produce 500 kW, which means 1000 kW for the ferry. The effect of the arrangement on the rotor system behavior is described.
At the time of writing this paper ABB has sold 6 GT35 units for operation in 3 fast ferries. The speed of the ferries varies between 40 knots and 60 knots. At the time of writing this paper, the first of the two HSS 900 ferries for Stena Line, Sweden, has just completed its first set of sea trials.
Limiting the Maintenance Impact of Frequency Regulation Duty on Simple and Combined Cycle Gas Turbine Power Plants
Authors: Rowen William I. 
Published: December 2014

As more new power plants based on gas turbines enter service, the need for these plants to participate in grid frequency regulation, as opposed to providing blocks of base load power on a dispatchable basis, increases dramatically, exposing this equipment to the potential for accelerated thermal fatigue duty. This paper proposes a methodology for quantifying and limiting the maintenance impact of rapid load changes imposed on gas turbines when required to provide frequency regulation service to the connected utility.
The paper includes a discussion of the need for prime movers to participate in system frequency regulation and the impact of this type of service on gas turbine operation. The physics of thermally induced low cycle fatigue is then discussed, and the relationships are quantified using a multiple time constant approach that provides guidance for estimating the transient thermal characteristics of the turbine airfoils that are susceptible to thermally induced low cycle fatigue. This is used to develop the thermo-mechanical relationships that are pertinent to gas turbines in generator drive service. Finally, this material is related back to operational considerations in utilizing gas turbines for system frequency regulation duty.
Advancements in Machinery Management Using the Measurement of Rotor Torsional Response
Authors: Thomson Alan S. 
Published: December 2014

Rotor torsional (angular, steady and dynamic) motion, in response to the interaction of torque and torsional/lateral cross coupled forces with torsional dynamic stiffness, exist in rotating and reciprocating machinery for many reasons. The dynamic torsional response however, is commonly not measured on a continual basis. In the torsional dynamic stiffness, damping parameters are generally several magnitudes weaker than their lateral counterpart. This yields the opportunity for torsional responses, especially when exciting a resonance, to produce relatively large deflections and corresponding stresses, sometimes large enough to cause machine failure.
Due to their rigid coupling, long shaft system lengths (a series of shafts coupled together), and large polar moments of inertia, the turbomachinery used in the power generation industry are particularly sensitive to forced torsional excitation. The forcing can come from many sources, including lateral forces which cross couple into torsional forces. Recent research introduces new sources of cross coupled excitation and a method to indirectly measure their and other effects on the mechanical integrity of the mechanical system.
A modified and a prototype technique for continuously measuring directly and indirectly the rotor torsional response, and using it to evaluate rotor torsional dynamic stiffness as a machinery management tool is discussed in this paper.
Reverse Engineered Part Development
Authors: Simandiri Sim S. , Wang K. H. 
Published: December 2014

Reverse engineering proceeds in the reverse of conventional manufacturing order, based on the pull system instead of the traditional push system. This paper is concerned with applying the reverse engineering concept to the development of parts. With this procedure the development of parts involves an iterative reverse process from the scanning of a developmental prototype towards the design model.
The focus is on the use of two set-ups of network in providing computerized data of the prototype that are exchangeable among Computer-Aided Design (CAD) and Computer-Aided Manufacturing (CAM) systems. The first set-up applies a direct approach to manipulate the scanned data in the CAM environment for generating Numerical Control (NC) programs used for machining the workpiece. The second set-up applies an indirect approach to manipulate the scanned data in a CAD environment prior to generating the NC programs. The major benefits gained from the reverse engineering application in the development of parts are also described.
A New Gas Turbine Cycle for Economical Power Boosting
Authors: Utamura Motoaki , Takehara Isao , Horii Nobuyuki , Kuwahara Takaaki 
Published: December 2014

A Moisture Air Turbine (MAT) cycle is proposed for improving the characteristics of land based gas turbine by injecting atomized water at inlet to compressor.
The power boosting mechanism of MAT is understood as composits of those of following existing systems: inlet air cooling system, inter-cooling and steam injection. Experiments using a 15MW class axial flow load compressor have been carried out to reveal that water evaporation in compressor could reduce compressor work in an efficient manner. Moreover, this technology has been demonstrated by means of 130MW class simple cycle gas turbine power plant to show that a small amount of water consumption is sufficient to increase power output. Very efficient evaporation could be achieved provided the size of water droplet is controlled properly. The amount of water consumption is much less than that of conventional inlet air cooling system with cooling tower for heat rejection.
Incorporating water droplet evaporation profile into consideration, realistic cycle calculation model has been developed to predict power output with water injection.
It has been shown that this technology is economically achievable. It should be stressed that contrary to well known evaporative cooler, MAT cycle could provide power output at a desired value within its capability regardless of ambient humidity condition.
Clavanin A Improves Outcome of Complications from Different Bacterial Infections
Authors: Silva Osmar N. , Fensterseifer Isabel C. M. , Rodrigues Elaine A. , Holanda Hortência H. S. , Novaes Natasha R. F. , Cunha Junia P. A. , Rezende Taia M. B. , Magalhães Kelly G. , Moreno Susana E. , Jerônimo Márcio S. , Bocca Anamélia L. , Franco Octavio L. 
Published: December 2014

ABSTRACT

The rapid increase in the incidence of multidrug-resistant infections today has led to enormous interest in antimicrobial peptides (AMPs) as suitable compounds for developing unusual antibiotics. In this study, clavanin A, an antimicrobial peptide previously isolated from the marine tunicate
Styela clava
, was selected as a purposeful molecule that could be used in controlling infection and further synthesized. Clavanin A was
in vitro
evaluated against
Staphylococcus aureus
and
Escherichia coli
as well as toward L929 mouse fibroblasts and skin primary cells (SPCs). Moreover, this peptide was challenged here in an
in vivo
wound and sepsis model, and the immune response was also analyzed. Despite displaying clear
in vitro
antimicrobial activity toward Gram-positive and -negative bacteria, clavanin A showed no cytotoxic activities against mammalian cells, and in acute toxicity tests, no adverse reaction was observed at any of the concentrations. Moreover, clavanin A significantly reduced the
S. aureus
CFU in an experimental wound model. This peptide also reduced the mortality of mice infected with
E. coli
and
S. aureus
by 80% compared with that of control animals (treated with phosphate-buffered saline [PBS]): these data suggest that clavanin A prevents the start of sepsis and thereby reduces mortality. These data suggest that clavanin A is an AMP that could improve the development of novel peptide-based strategies for the treatment of wound and sepsis infections.
Effect of Reduced Oxygen on the Antifungal Susceptibility of Clinically Relevant Aspergilli
Authors: Binder Ulrike , Maurer Elisabeth , Lackner Michaela , Lass-Flörl Cornelia 
Published: December 2014

ABSTRACT

The influence of hypoxia on the
in vitro
activities of amphotericin B, azoles, and echinocandins against
Aspergillus
spp. was evaluated by comparing MICs, minimal fungicidal concentrations (MFCs), and epidemiological cutoffs (ECOFFs). Changes of MIC distributions due to hypoxia largely depend on the method, the species, and the growth ability under hypoxia. The activities of antifungals were not significantly altered under hypoxia, except for
Aspergillus terreus
, for which the activity changed from fungicidal to fungistatic.
Rapid Testing Using the Verigene Gram-Negative Blood Culture Nucleic Acid Test in Combination with Antimicrobial Stewardship Intervention against Gram-Negative Bacteremia
Authors: Bork Jacqueline T. , Leekha Surbhi , Heil Emily L. , Zhao LiCheng , Badamas Rilwan , Johnson J. Kristie 
Published: December 2014

ABSTRACT

Rapid identification of microorganisms and antimicrobial resistance is paramount for targeted treatment in serious bloodstream infections (BSI). The Verigene Gram-negative blood culture nucleic acid test (BC-GN) is a multiplex, automated molecular diagnostic test for identification of eight Gram-negative (GN) organisms and resistance markers from blood culture with a turnaround time of approximately 2 h. Clinical isolates from adult patients at the University Maryland Medical Center with GN bacteremia from 1 January 2012 to 30 June 2012 were included in this study. Blood culture bottles were spiked with clinical isolates, allowed to incubate, and processed by BC-GN. A diagnostic evaluation was performed. In addition, a theoretical evaluation of time to effective and optimal antibiotic was performed, comparing actual antibiotic administration times from chart review (“control”) to theoretical administration times based on BC-GN reporting and antimicrobial stewardship team (AST) review (“intervention”). For organisms detected by the assay, BC-GN correctly identified 95.6% (131/137), with a sensitivity of 97.1% (95% confidence interval [CI], 90.7 to 98.4%) and a specificity of 99.5% (95% CI, 98.8 to 99.8%). CTX-M and OXA resistance determinants were both detected. Allowing 12 h from Gram stain for antibiotic implementation, the intervention group had a significantly shorter duration to both effective (3.3 versus 7.0 h;
P
< 0.01) and optimal (23.5 versus 41.8 h;
P
< 0.01) antibiotic therapy. BC-GN with AST intervention can potentially decrease time to both effective and optimal antibiotic therapy in GN BSI.