bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fate of Ash Forming Elements in Gas Turbine Combustion of Pulverized Wood: Chemical Equilibrium Model Calculations
Authors: Kallner Per , Nordin Anders , Backman Rainer 
Published: January 2015

A new concept for direct combustion of wood in a gas turbine is presently developed and tested in Sweden. The process is based on a fuel rich cyclone gasifier/separator and a direct coupled modified standard gas turbine combustor. A main concern is the behaviour of ash forming elements in the turbine. A picture of this can be obtained with chemical equilibrium calculations.
The objective of the present work was to determine the equilibrium speciation of the ash forming elements from wood passing through the turbine of a gas turbine engine for varying feed characteristics and operating conditions. In addition, the differences between using only stoichiometric and using non-ideal solution models as thermodynamic input data were illustrated.
The equilibrium relationships at the turbine stage were evaluated in a parametric study, utilizing statistical experimental designs to systematically perform the model calculations. A wide range of operating conditions, wood compositions and cyclone elemental retention efficiencies were thereby covered.
The results show considerable variation in the alkali speciation as well as in devolitalization and condensation temperatures, depending on the elemental composition. Plots of the effects of the most influential variables are presented and results not directly displayed in this work are illustrated with model equations provided.
Protective Coatings and Degradation Experiences for First Stage Buckets on GE MS-5002B/C Gas Turbines
Authors: Boestaman Refrizal , Swaminathan V. P. , Bernstein H. L. 
Published: January 2015

PT Arun operates 21 GE Model MS-5002 B/C gas turbines as mechanical drive with a total power of 514 MW, and a total of 2.7 million hours of accumulated operation. The first generations of simple cycle gas turbines were designed at 1700 F (927 C) firing temperature using first stage buckets design cast from IN-738LC and coated with a conventional 2-phase platinum aluminide coating (Pt-Al). Since 1989, the output power was increased by raising gas turbine firing temperature to 1770 F (965 C). This uprate was implemented by using first stage buckets cast from GTD-111 DS and coated with GT-29 Plus.
Metallurgical examination of these coatings at various operating hours have been performed to check their performance and the cause of coating degradation. These results are considered for future coating selection.
In the last two years PT Arun has explored a new single phase NiCoCrAlY coating and a single phase Pt-Al diffusion coating using chemical vapor disposition process as an alternate to GT-29 plus coating replacement. Both of these coatings are used at PT Arun and have accumulated 32,400 hours for NiCoCrAlY or GT-33 and 2880 hours for single phase Pt-Al or MDC-150L coating as of June 1996. The information regarding qualification of these alternate coatings (zero running hours) will be discussed in this paper.
Combustion Instability Investigations on the BR710 Jet Engine
Authors: Konrad Wolfgang , Brehm Norbert , Kameler Frank , Freeman Chris , Day Ivor J. 
Published: January 2015

During the development of the BR710 jet engine audible combustor instabilities (termed ‘rumble’) occurred. Amplitudes measured with test cell microphones were up to 130 dB at around 100 Hz. Disturbances of this amplitude are clearly undesirable, even if only present during start-up, and a research program was initiated to eliminate the problem.
Presented here is the methodical and structured approach used to identify, understand, and remove the instability. Some reference is made to theory, which was used for guidance, but the focus of the work is on the research done to find the cause of the problem and to correct it. The investigation followed two separate, but parallel, paths — one looking in detail at individual ‘components of the engine to identify possible involvement in the instability and the other looking at the pressure signals from various parts of a complete engine to help pin-point the source of the disturbance.
The main cause of the BR710 combustor rumble was found to be a self-excited aerodynamic instability arising from the design of the fuel injector head. In the end, minor modifications lead to spray pattern changes which greatly reduced the combustor noise. As a result of this work, new recommendations are made for reducing the risk of combustion instabilities in jet engines.
Neural Networks for the Diagnostics of Gas Turbine Engines
Authors: Torella G. , Lombardo G. 
Published: January 2015

The paper describes the activities carried out for developing and testing Back Propagation Neural Networks (BPNN) for the gas turbine engine diagnostics.
One of the aims of this study was to analyze the problems encountered during training using large number of patterns.
Each pattern contains information about the engine thermodynamic behaviour when there is a fault in progress.
Moreover the research studied different architectures of BPNN for testing their capability to recognize patterns even when information is noised.
The results showed that it is possible to set-up and optimize suitable and robust Neural Networks useful for gas turbine diagnostics. The methods of Gas Path Analysis furnish the necessary data and information about engine behaviour.
The best architecture, among the ones studied, is formed by 13, 26 and 47 neurons in the input, hidden and output layer respectively. The investigated Nets have shown that the best encoding of faults is the one using a unitary diagonal matrix.
Moreover the calculation have identified suitable laws of learning rate factor (LRF) for improving the learning rate.
Finally the authors used two different computers. The first one has a classical architecture (sequential, vectorial and parallel). The second one is the Neural Computer, SYNAPSE-1, developed by Siemens.
Integrated Coal Gasification Combined Cycle: Current Experience — Future Promise
Authors: Kaupang Bjorn , Todd Douglas M. 
Published: January 2015

Significant progress has been made in the installation and initial operation of several IGCC power plants. At least six IGCC projects are scheduled to enter commercial operation in the USA and in Europe during 1996. Several additional IGCC projects are under construction or under development using many different gasification systems. Gas turbine manufacturers introduced advanced gas turbine technology in 1995, resulting in IGCC efficiency for coal and heavy oil-fired plants of up to 50% (LHV) with plant costs consistent with conventional steam plants. Gas turbine developments specifically aimed at IGCC applications allow the use of environmentally low quality fuels without added impact on the environment.
This paper discusses the current operating experience of several of the initial IGCC plants and illustrates the very attractive fuels flexibility with the combined-cycle plants burning naphtha or distillate oils initially with later conversions to IGCC burning lignite, heavy oil or orimulsion. This paper also discusses the heat rate and output performance capabilities of the IGCC with H level gas turbine technology and the resulting impacts on the cost of electricity from IGCC plants.
Experimental Refinement of Technologies for Environmental Update of Gas Turbine Units Applied to Electrogenerator Driving
Authors: Soudarev A. V. , Vinogradov E. D. , Zakharov Ju. I. 
Published: January 2015

The results of experimental elaboration of engineering approaches relating to environmental update of combustors for the GTK-10 10 MW, GTG-1500 1.5 MW and GT-100 100 MW gas turbine engines are presented. The combustor update was carried out by a technique of directed dosed air blow into the maximum temperature zone with in the fire space.
The advantages of the technique are as follows:
• feasibility of reduction of Nox concentration in waste gases to 50 ppm;
• simplicity and adaptability to manufacture of the structure;
• no need in changing the design of the engine components and systems;
• short-time outage of the unit at update.
Industrial Power Company Cogeneration at Eastern Industrial Estate, Map Ta Phut, Thailand: First Single Shaft Combined Cycle Application of 50 MW GT8C
Authors: van der Linden Septimus , Baerfuss Paul A. , Vonau Karl-Heinz 
Published: January 2015

Smaller CC plants below 80 MW offer economic solutions in cogeneration to industrial parks in the South East Asian power market which is typically dominated by large gas turbines and power plants. For the Industrial Power CO-GEN project, the single shaft power train arrangement for combined cycle/cogeneration is the first GT8C application of reference plant concepts.
Commercial operation will commence in September 1997 with first components to be shipped in October 1996. This paper describes the GT8C single shaft combined cycle arrangement applied to industrial power cogeneration as well as some specifics of the Industrial Power Co. Ltd. project (IP CO-GEN project) at Eastern Industrial Estate, Map Ta Phut, Thailand related to plant layout, operating and control philosophy.
Development in Industrial Scale Gas Turbine Systems
Authors: Anson Donald , Duffy Thomas E. , White David , Waslo S. 
Published: January 2015

The variety of applications in which small industrial gas turbines are used requires that they be readily capable of integration into cogeneration schemes and combined gas/steam cycles as well as providing reliable and efficient stand-alone performance. Several gas turbine based power systems are reviewed briefly. Simple cycle and recuperative engines, and possibly intercooled/recuperative engines, appear to be the most likely primary arrangements for developing more efficient industrial gas turbine based systems. These systems include high pressure, high temperature steam turbines recently developed. When coupled with high pressure, high temperature steam generators, industrial scale simple cycle gas turbines can offer high electrical generation efficiencies with excellent turndown and overall heat utilization in cogeneration mode.
Basically, high efficiency depends on firing temperature (TRIT). Firing temperature will continue to increase using advanced metal casting and cooling techniques developed in the aircraft engine sector, and possibly ceramics, which are more applicable in industrial engines than elsewhere. Electrical efficiencies for rated outputs of 5–20 MW will be 32–35 percent for simple cycle gas turbines, up to 42 percent in recuperative engines and cogeneration systems, and 45 percent in combined cycles.
The paper lists references describing in detail many of the developments that have contributed to state-of-the-art industrial turbine design.
Slurry Coating Systems for Low and High Temperature Turbine Protection: New Developments
Authors: Thoma M. , Morant M. 
Published: January 2015

Inorganic slurry coatings based on a ceramic binder which contains aluminum or aluminum and silicon are very effective coatings in engines and gas turbines.
All these coatings contain much chromic acid, causing health problems when applied by the usual spraying technique. A new generation of slurry coatings with minimized Cr6+ (<0.5% weight) content has been developed.
- Ceral 114 systems as Al ceramic overlay coatings for corrosion protection of steel compressor parts. The excellent properties are presented.
- Ceral 10 aluminide silicon doped for hot corrosion protection of turbine components made of superalloys. Coating structures and properties are discussed.
A Novel CDK7 Inhibitor of the Pyrazolotriazine Class Exerts Broad-Spectrum Antiviral Activity at Nanomolar Concentrations
Authors: Hutterer Corina , Eickhoff Jan , Milbradt Jens , Korn Klaus , Zeitträger Isabel , Bahsi Hanife , Wagner Sabrina , Zischinsky Gunther , Wolf Alexander , Degenhart Carsten , Unger Anke , Baumann Matthias , Klebl Bert , Marschall Manfred 
Published: January 2015

ABSTRACT

Protein kinases represent central and multifunctional regulators of a balanced virus-host interaction. Cyclin-dependent protein kinase 7 (CDK7) plays crucial regulatory roles in cell cycle and transcription, both connected with the replication of many viruses. Previously, we developed a CDK7 inhibitor, LDC4297, that inhibits CDK7
in vitro
in the nano-picomolar range. Novel data from a kinome-wide evaluation (>330 kinases profiled
in vitro
) demonstrate a kinase selectivity. Importantly, we provide first evidence for the antiviral potential of the CDK7 inhibitor LDC4297, i.e., in exerting a block of the replication of human cytomegalovirus (HCMV) in primary human fibroblasts at nanomolar concentrations (50% effective concentration, 24.5 ± 1.3 nM). As a unique feature compared to approved antiherpesviral drugs, inhibition occurred already at the immediate-early level of HCMV gene expression. The mode of antiviral action was considered multifaceted since CDK7-regulated cellular factors that are supportive of HCMV replication were substantially affected by the inhibitors. An effect of LDC4297 was identified in the interference with HCMV-driven inactivation of retinoblastoma protein (Rb), a regulatory step generally considered a hallmark of herpesviral replication. In line with this finding, a broad inhibitory activity of the drug could be demonstrated against a selection of human and animal herpesviruses and adenoviruses, whereas other viruses only showed intermediate drug sensitivity. Summarized, the CDK7 inhibitor LDC4297 is a promising candidate for further antiviral drug development, possibly offering new options for a comprehensive approach to antiviral therapy.
Depot Medroxyprogesterone Acetate in Combination with a Twice-Daily Lopinavir-Ritonavir-Based Regimen in HIV-Infected Women Showed Effective Contraception and a Lack of Clinically Significant Interactions, with Good Safety and Tolerability: Results of the ACTG 5283 Study
Authors: Luque Amneris E. , Cohn Susan E. , Park Jeong-Gun , Cramer Yoninah , Weinberg Adriana , Livingston Elizabeth , Klingman Karin L. , Aweeka Francesca , Watts D. Heather 
Published: January 2015

ABSTRACT

We conducted an open-label, steady-state pharmacokinetic (PK) study of drug-drug interactions between depot medroxyprogesterone acetate (DMPA) and twice-daily lopinavir (LPV) plus low-dose ritonavir (RTV) (LPV/r) among 24 HIV-infected women and compared the results to those for HIV-infected women receiving DMPA while on no antiretroviral therapy or on nucleosides only (
n
= 14 subjects from the control arm of AIDS Clinical Trials Group [ACTG] study 5093). The objectives of the study were to address the effect of LPV/r on DMPA and to address the effect of DMPA on LPV/r therapy. PK parameters were estimated using noncompartmental analysis with between-group comparisons of medroxyprogesterone acetate (MPA) PKs and within-subject comparisons of LPV and RTV PKs before and 4 weeks after DMPA dosing. Plasma progesterone concentrations were measured every 2 weeks after DMPA dosing through week 12. Although the MPA area under the concentration-time curve and maximum concentration of drug in plasma were statistically significantly increased in the study women on LPV/r compared to those in the historical controls, these increases were not considered clinically significant. There were no changes in LPV or RTV exposure after DMPA. DMPA was well tolerated, and suppression of ovulation was maintained. (This study has been registered at ClinicalTrials.gov under registration no. NCT01296152.)
Major Pathways of Polymyxin-Induced Apoptosis in Rat Kidney Proximal Tubular Cells
Authors: Azad Mohammad A. K. , Akter Jesmin , Rogers Kelly L. , Nation Roger L. , Velkov Tony , Li Jian 
Published: January 2015

ABSTRACT

Identifying the pathways involved in the apoptotic cell death that is associated with polymyxin-induced nephrotoxicity is crucial for the development of strategies to ameliorate this dose-limiting side effect and for the development of novel safer polymyxins. The primary aim of this study was to identify the major pathways which lead to polymyxin-induced apoptosis in cultured rat kidney proximal tubular cells (NRK-52E). Caspase-3, -8, and -9 were activated by polymyxin B treatment in a concentration-dependent manner. Concentration- and time-dependent expression of FasL and deformation of mitochondrial morphology were revealed following polymyxin B treatment. The proportion of cells with filamentous mitochondria (regular morphology) following an 8-h treatment with 1.0 mM polymyxin B was 56.2% ± 9.7% (
n
= 3). This was decreased to 30.7% ± 7.5% when the polymyxin B concentration was increased to 2.0 mM. The mitochondrial membrane potential (Δψ
m
) decreased to 14.1% ± 2.9% in the cells treated with 1.0 mM polymyxin B for 24 h (
n
= 3) compared to that in the untreated control group. Concomitantly, concentration- and time-dependent production of mitochondrial superoxide was also observed. This study is the first to have demonstrated that polymyxin-induced apoptosis is mediated through both the death receptor and mitochondrial pathways in cultured renal tubular cells. It provides key information not only for the amelioration of polymyxin-induced nephrotoxicity but also for the discovery of novel safer polymyxin-like antibiotics against Gram-negative “superbugs.”
The C-Terminal Heavy-Chain Domain of Botulinum Neurotoxin A Is Not the Only Site That Binds Neurons, as the N-Terminal Heavy-Chain Domain Also Plays a Very Active Role in Toxin-Cell Binding and Interactions
Authors: Ayyar B. Vijayalakshmi , Aoki K. Roger , Atassi M. Zouhair 
Published: January 2015

ABSTRACT

Botulinum neurotoxins (BoNTs) possess unique specificity for nerve terminals. They bind to the presynaptic membrane and then translocate intracellularly, where the light-chain endopeptidase cleaves the SNARE complex proteins, subverting the synaptic exocytosis responsible for acetylcholine release to the synaptic cleft. This inhibits acetylcholine binding to its receptor, causing paralysis. Binding, an obligate event for cell intoxication, is believed to occur through the heavy-chain C-terminal (H
C
) domain. It is followed by toxin translocation and entry into the cell cytoplasm, which is thought to be mediated by the heavy-chain N-terminal (H
N
) domain. Submolecular mapping analysis by using synthetic peptides spanning BoNT serotype A (BoNT/A) and mouse brain synaptosomes (SNPs) and protective antibodies against toxin from mice and cervical dystonia patients undergoing BoNT/A treatment revealed that not only regions of the H
C
domain but also regions of the H
N
domain are involved in the toxin binding process. Based on these findings, we expressed a peptide corresponding to the BoNT/A region comprising H
N
domain residues 729 to 845 (H
N
729–845). H
N
729–845 bound directly to mouse brain SNPs and substantially inhibited BoNT/A binding to SNPs. The binding involved gangliosides GT1b and GD1a and a few membrane lipids. The peptide bound to human or mouse neuroblastoma cells within 1 min. Peptide H
N
729–845 protected mice completely against a lethal BoNT/A dose (1.05 times the 100% lethal dose). This protective activity was obtained at a dose comparable to that of the peptide from positions 967 to 1296 in the H
C
domain. These findings strongly indicate that H
N
729–845 and, by extension, the H
N
domain are fully programmed and equipped to bind to neuronal cells and in the free state can even inhibit the binding of the toxin.
Blocking Yersiniabactin Import Attenuates Extraintestinal Pathogenic Escherichia coli in Cystitis and Pyelonephritis and Represents a Novel Target To Prevent Urinary Tract Infection
Authors: Brumbaugh Ariel R. , Smith Sara N. , Subashchandrabose Sargurunathan , Himpsl Stephanie D. , Hazen Tracy H. , Rasko David A. , Mobley Harry L. T. 
Published: January 2015

ABSTRACTThe emergence and spread of extended-spectrum beta-lactamases and carbapenemases among common bacterial pathogens are threatening our ability to treat routine hospital- and community-acquired infections. With the pipeline for new antibiotics virtually empty, there is an urgent need to develop novel therapeutics. Bacteria require iron to establish infection, and specialized pathogen-associated iron acquisition systems like yersiniabactin, common among pathogenic species in the familyEnterobacteriaceae, including multidrug-resistantKlebsiella pneumoniaeand pathogenicEscherichia coli, represent potentially novel therapeutic targets. Although the yersiniabactin system was recently identified as a vaccine target for uropathogenicE. coli(UPEC)-mediated urinary tract infection (UTI), its contribution to UPEC pathogenesis is unknown. Using anE. colimutant (strain 536ΔfyuA) unable to acquire yersiniabactin during infection, we established the yersiniabactin receptor as a UPEC virulence factor during cystitis and pyelonephritis, a fitness factor during bacteremia, and a surface-accessible target of the experimental FyuA vaccine. In addition, we determined through transcriptome sequencing (RNA-seq) analyses of RNA fromE. colicausing cystitis in women that iron acquisition systems, including the yersiniabactin system, are highly expressed by bacteria during natural uncomplicated UTI. Given that yersiniabactin contributes to the virulence of several pathogenic species in the familyEnterobacteriaceae, including UPEC, and is frequently associated with multidrug-resistant strains, it represents a promising novel target to combat antibiotic-resistant infections.
Structure-Function Analysis of VapB4 Antitoxin Identifies Critical Features of a Minimal VapC4 Toxin-Binding Module
Authors: Jin Guangze , Pavelka Martin S. , Butler J. Scott 
Published: January 2015

ABSTRACTBacterial toxin-antitoxin systems play a critical role in the regulation of gene expression, leading to developmental changes, reversible dormancy, and cell death. Type II toxin-antitoxin pairs, composed of protein toxins and antitoxins, exist in nearly all bacteria and are classified into six groups on the basis of the structure of the toxins. The VapBC group comprises the most common type II system and, like other toxin-antitoxin systems, functions to elicit dormancy by inhibiting protein synthesis. Activation of toxin function requires protease degradation of the VapB antitoxin, which frees the VapC toxin from the VapBC complex, allowing it to hydrolyze the RNAs required for translation. Generally, type II antitoxins bind with high specificity to their cognate toxins via a toxin-binding domain and endow the complex with DNA-binding specificity via a DNA-binding domain. Despite the ubiquity of VapBC systems and their critical role in the regulation of gene expression, few functional studies have addressed the details of VapB-VapC interactions. Here we report on the results of experiments designed to identify molecular determinants of the specificity of theMycobacterium tuberculosisVapB4 antitoxin for its cognate VapC4 toxin. The results identify the minimal domain of VapB4 required for this interaction as well as the amino acid side chains required for binding to VapC4. These findings have important implications for the evolution of VapBC toxin-antitoxin systems and their potential as targets of small-molecule protein-protein interaction inhibitors.IMPORTANCEVapBC toxin-antitoxin pairs are the most widespread type II toxin-antitoxin systems in bacteria, where they are thought to play key roles in stress-induced dormancy and the formation of persisters. The VapB antitoxins are critical to these processes because they inhibit the activity of the toxins and provide the DNA-binding specificity that controls the synthesis of both proteins. Despite the importance of VapB antitoxins and the existence of several VapBC crystal structures, little is known about their functional featuresin vivo. Here we report the findings of the first comprehensive structure-function analysis of a VapB toxin. The results identify the minimal toxin-binding domain, its modular antitoxin function, and the specific amino acid side chains required for its activity.