bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vibration and Buckling of Square Plates Containing Central Holes
Authors: Sabir A. B. , Davies G. T. 
Published: December 2014

The finite element method is used to determine the natural frequencies of flat square plates containing centrally located circular or square holes. The plates are subjected to either inplane uniaxial, biaxial or uniformly distributed shear along the four outer edges. These edges are either simply supported or clamped.
To determine the stiffness and mass matrices, non conforming rectangular and triangular displacement elements are used to model the out of plane behaviour of the plate. The inplane stress distribution within the plates, which are required in the analysis are determined by using inplane finite elements having displacement fields based on assumed strains. These satisfy the exact requirements of strain free rigid body modes of displacements.
The natural frequencies of simply supported and clamped plates are initially determined when no inplane loads are applied. This showed the influence of the size of the hole on the natural circular frequency. These plates were then subjected to inplane loads and the effect of these forces on the natural frequencies are given. The results show the natural frequencies of square plates with central circular holes decrease with increasing compressive forces, and that the frequencies become zero when the compressive forces are equal to the elastic buckling loads of the plates.
By repeating this process for all boundary conditions and applied loads a comprehensive set of results is obtained for the buckling and vibrational properties of square plates containing centrally located holes.
Natural Frequency Analysis of Elastic Plate
Authors: Saijo O. , Eto H. 
Published: December 2014

Large scale floating structures, such as floating airport and amusement park having two dimensional expanse in horizontal direction, which structural concept can be considered as plate-type structural system. This structural system has a great deal of potential to be applied to oceanic structures like a artificial ground. This practical fabrication will be done by a combination of units. The hydroelastic interaction problem and structural design have attracted the attention of researchers and structural engineers.
This paper presents consideration and conclusion through the numerical calculation results of the natural frequency studied under the various supporting conditions by developed computer program. The theoretical development is obtained by a way of combination of finite element method (FEM) and boundary integral equation method (BIEM). As to natural frequency analysis of oceanic structures based on the fluid-structure interaction, in general, there is an assumption to make it possible by estimating properly the added mass of the structure surrounding by water. The added mass of floating plate obtained by BIEM is modified and transformed into mass matrix of plate in FEM analysis. Herein, FEM analysis is based on the bending vibration assumption.
Real Time Linear Simulation and Control for the Small Aircraft Turbojet Engine
Authors: Kong C. D. , Kim S. K. 
Published: December 2014

The performance of the aero gas turbine engine requires optimization because it is directly related to overall aircraft performance.
In this study, a modified DYNGEN, a dynamic simulation program with component maps of the small aircraft turbojet engine, was used. Nonlinear dynamic simulation was performed to predict overall engine performance.
Each response characteristic of various cases, such as the 6% rpm step model, the 5% rpm step model, the 3% rpm step model, and the real-time linear model of the interpolation scheme within the operating range were compared. Among them, the real time linear model was selected for the turbojet engine with nonlinear characteristics.
Finally control schemes such as the PI (Proportional-Integral Controller) and the LQR (Linear Quadratic Regulator) were applied to optimize engine performance.
As a result of comparison of the PI and the LQR controller, the overshoot of the turbine inlet temperature was effectively eliminated by the LQR controller with the proper control gain K.
Phase 1 Testing of the Redundant Internal Mechanical Start System for the Ship Service Gas Turbine Generator Sets on the U.S. Navy’s DDG-51 Class Ships
Authors: Russom Dennis M. , Masincup William E. , Eghtessad John 
Published: December 2014

The Redundant Independent Mechanical Start System (RIMSS) is a gas turbine powered, mechanically coupled start system for the Allison AG9140 Ship Service Gas Turbine Generator Sets (SSGTGs) of the U.S. Navy’s DDG-51 Class ships. The system will be original equipment on DDG-86 and follow. It will also be a candidate for backfit onto earlier DDG-51 Class ships.
This paper describes RIMSS and details a very successful phase of the RIMSS program. All U.S. Navy testing was conducted on an Allison AG9140 located at the Carderock Division, Naval Surface Warfare Center-Ship Systems Engineering Station, DDG-51 Gas Turbine Ship Land Based Engineering Site (NSWCCD-SSES LBES), Figure 1. The test agenda included 516 SSGTG starts and 75 SSGTG motoring cycles. The primary goal was to validate engine life predictions for the Allison 250-C20B gas turbine engine in the RIMSS application. A secondary goal was to evaluate the overall RIMSS system during an extended period of operation.
Lessons Learned From Durability Surveillance of Advanced Gas Turbines
Authors: Touchton George L. , Quentin George H. , Mastrodonato Bart 
Published: December 2014

New high temperature materials and improved blade cooling techniques have led 10 design of advanced models of industrial gas turbines with inlet or “firing” temperatures of 2350 degrees F. and higher. All major vendors now offer large new commercial gas turbine-generators, with outputs of 150 megawatts and higher, based on these new designs. These new turbine units offer higher overall performance and fuel efficiencies, with promise of better reliability and availability, as well as lower operating and maintenance costs.
EPRI began to assess the durability of early models of these advanced gas turbines (AGT) in 1991, by closely monitoring their performance during electric utility operation. The durability surveillance program, involving several AGT installations outlined below, will be described. However, only the first two sites involving GE units have produced a substantial operating history for discussion. The latter two sites have only recently had new AGT units installed by ABB and Siemens respectively. At the time of this writing, those new units are still being readied for utility operation. Their operating history under the durability surveillance program will be monitored, and discussed in a future paper.
• General Electric Gas Turbine Model MS7001F in peaking service at Potomac Electric Power Co. Station H at Dickerson, Maryland.
• General Electric Gas Turbine Model MS7001FA in baseload service at Florida Power & Light Co. Martin Plant at Indiantown, Florida.
• ASEA Brown Bovert Gas Turbine Model GT 24 initially in peaking service at Jersey Central Power & Light Co.(now GPU GenCo) Gilbert Station at Milford, New Jersey.
• Siemens Gas Turbine Model V84.3A in peaking service at Kansas City Power & Light Co. Hawthorn Station at Kansas City, Missouri.
The purpose is to determine the prospects for improved unit life cycle costs as a result of higher levels of performance, availability, reliability, and mantainability achieved by adding these engines to the industry fleet. This paper will describe the initial results from the Durability Surveillance studies, including observations from unit maintenance inspections as well as the output of advanced diagnostics and monitoring systems.
Influence of the Control Logic on Gas Turbine Operation
Authors: Bettocchi R. , Spina P. R. 
Published: December 2014

This paper presents an analysis of the influence of control logic on gas turbine operation, when machine load adjustments are carried out.
An examination is made of the control logics that are possible for a two-shaft gas turbine with variable power turbine nozzle in order to reach the following objectives:
- operation in maximum efficiency conditions;
- operation in the conditions of maximum thermal power of exhaust gases at the turbine outlet;
- operation at constant turbine outlet temperature;
- operation with the maximum Surge Margin.
The control logics necessary for reaching the predetermined objectives in the part-load operation are provided by the map of gas turbine’s main performance, thermodynamic and control parameters.
A Techno-Economic Computational Tool for Power Generation Project Assessments and Life Cycle Risk Management
Authors: Gayraud Stéphane , Singh Riti 
Published: December 2014

The growing desire for sponsors of power generation projects to share risk with the lenders has promoted the use of computational tools, simulating and evaluating from a techno-economic viewpoint long-term, high-risk projects. Such models need to include reliable engine diagnostics, life-cycle costing and risk analysis technique.
This paper presents a Decision Support System (DSS) for the assessment of power generation projects using industrial gas turbines. The software, programmed in Visual Basic in Excel, runs the object-oriented software Pythia which has been developed by the Department of Propulsion, Power and Automotive Engineering at Cranfield University and which can perform gas turbine performance calculations, including off-design conditions, with or without degradation effects providing thus very reliable engine diagnostics. Moreover, a life cycle cost, assessed using manufacturer methodology for instance, can be integrated into the economic model. The degree of uncertainty relating to technical and economic factors is assessed using a normal distribution and the level of risk can then be evaluated using a risk analysis technique based upon the Monte Carlo Method. The DSS therefore provides charts and result tables to support the decision making, allowing the user to achieve a good level of confidence using new techniques of risk management.
Environmental Upgrading of GTN-16 Gas-Pumping Unit Combustion Chamber
Authors: Soudarev A. V. , Zakharov Yu. I. , Vinogradov E. D. , Gutnik M. N. 
Published: December 2014

The results of research into development of engineering approaches to environmental update of the GTN-16 16 MW gas-pumping unit combustor are presented. The built-in “disc” combustor of the GTN-16 is noted for having a small length and very low hydraulic resistances. The multi-burner low-NOx combustor design was developed in a test rig. The “lean” fuel/air premix combustion was adopted as the basis for the design.
The proposed environmental update of the GTN-16 combustor does not bring about any changes in the most costly material-intensive and labour-consuming components of the combustor, viz. casing, frame, liners. No changes were also made in the automatic control system. It is noteworthy that a similar approach is appropriate for the “Turbomotorny Zavod” (Ekaterinburg, Russia) GTN-25 type 25 MW unit.
High Efficiency-Coal and Gas (HE-C&G): A Hybrid Power Plant Concept Iintegrating ABB’s GT24/GT26 Gas Turbines With Conventional Steam Power Plants for Competitive Power Generation With High Dispatch Flexibility
Authors: Fetescu Mircea 
Published: December 2014

The electric power generation world is currently confronted with new challenges: deregulation, open competition, new players entering the business, new regulations governing the return on investment, increased complexity and risk.
In order to maintain or enhance their competitive position the electricity generators have as main objectives to lower generating costs, increase operating and dispatching flexibility and manage fuel related risks: availability, supply diversification, prices and price escalation and finally to capture value added profits.
In order to meet new requirements of electricity generators, ABB has developed a hybrid power plant concept integrating the sequential combustion gas turbines GT24/GT26 with existing or new conventional steam power plants: the High Efficiency Coal and Gas (HE-C&G).
The HE-C&G, with its unique design, operating and dispatching flexibility, provides our customers with the benefits of competitive power generation: the owner/operator can optimise — on line — the plant fuel and O&M costs, increase the availability, extend economic life and lower the environmental impact of the power plant. And even more, the HE-C&G creates the ability to benefit of the market opportunities: buy cheaper fuels and sell the electricity when profitable.
This paper evaluates the feasibility of combining conventional steam power plants with sequential combustion gas turbines GT24/GT26 and recommends the HE-C&G as one of the most competitive alternatives for power generation, especially for re-evaluation of existing assets and positioning in the competitive environment.
Effects of Tigecycline and Vancomycin Administration on Established Clostridium difficile Infection
Authors: Theriot Casey M. , Schumacher Cassie A. , Bassis Christine M. , Seekatz Anna M. , Young Vincent B. 
Published: December 2014

ABSTRACT

The glycylcycline antibiotic tigecycline was approved in 2005 for the treatment of complicated skin and soft tissue infections and complicated intra-abdominal infections. Tigecycline is broadly active against both Gram-negative and Gram-positive microorganisms, including
Clostridium difficile
. Tigecycline has a low MIC against
C. difficile
in vitro
and thus may represent an alternate treatment for
C. difficile
infection (CDI). To assess the use of tigecycline for treatment of established CDI, 5- to 8-week-old C57BL/6 mice were colonized with
C. difficile
strain 630. After
C. difficile
colonization was established, mice (
n
= 10 per group) were treated with either a 5-day course of tigecycline (6.25 mg/kg every 12 h subcutaneously) or a 5-day course of vancomycin (0.4 mg/ml in drinking water) and compared to infected, untreated control mice. Mice were evaluated for clinical signs of CDI throughout treatment and at 1 week posttreatment to assess potential for disease development. Immediately following a treatment course,
C. difficile
was not detectable in the feces of vancomycin-treated mice but remained detectable in feces from tigecycline-treated and untreated control mice. Toxin activity and histopathological inflammation and edema were observed in the ceca and colons of untreated mice; tigecycline- and vancomycin-treated mice did not show such changes directly after treatment. One week after the conclusion of either antibiotic treatment,
C. difficile
load, toxin activity, and histopathology scores increased in the cecum and colon, indicating that
C. difficile
-associated disease occurred.
In vitro
growth studies confirmed that subinhibitory concentrations of tigecycline were able to suppress toxin activity and spore formation of
C. difficile
, whereas vancomycin did not. Taken together, these data show how tigecycline is able to alter
C. difficile
pathogenesis in a mouse model of CDI.
A Novel CO-Responsive Transcriptional Regulator and Enhanced H
2
Production by an Engineered Thermococcus onnurineus NA1 Strain
Authors: Kim Min-Sik , Choi Ae Ran , Lee Seong Hyuk , Jung Hae-Chang , Bae Seung Seob , Yang Tae-Jun , Jeon Jeong Ho , Lim Jae Kyu , Youn Hwan , Kim Tae Wan , Lee Hyun Sook , Kang Sung Gyun 
Published: December 2014

ABSTRACT

Genome analysis revealed the existence of a putative transcriptional regulatory system governing CO metabolism in
Thermococcus onnurineus
NA1, a carboxydotrophic hydrogenogenic archaeon. The regulatory system is composed of CorQ with a 4-vinyl reductase domain and CorR with a DNA-binding domain of the LysR-type transcriptional regulator family in close proximity to the CO dehydrogenase (CODH) gene cluster. Homologous genes of the CorQR pair were also found in the genomes of
Thermococcus
species and “
Candidatus
Korarchaeum cryptofilum” OPF8. In-frame deletion of either
corQ
or
corR
caused a severe impairment in CO-dependent growth and H
2
production. When
corQ
and
corR
deletion mutants were complemented by introducing the
corQR
genes under the control of a strong promoter, the mRNA and protein levels of the CODH gene were significantly increased in a ΔCorR strain complemented with integrated
corQR
(ΔCorR/
corQR
↑
) compared with those in the wild-type strain. In addition, the ΔCorR/
corQR
↑
strain exhibited a much higher H
2
production rate (5.8-fold) than the wild-type strain in a bioreactor culture. The H
2
production rate (191.9 mmol liter
−1
h
−1
) and the specific H
2
production rate (249.6 mmol g
−1
h
−1
) of this strain were extremely high compared with those of CO-dependent H
2
-producing prokaryotes reported so far. These results suggest that the
corQR
genes encode a positive regulatory protein pair for the expression of a CODH gene cluster. The study also illustrates that manipulation of the transcriptional regulatory system can improve biological H
2
production.
Genotypic and Phenotypic Characterization of Escherichia coli Isolates from Feces, Hands, and Soils in Rural Bangladesh via the Colilert Quanti-Tray System
Authors: Julian Timothy R. , Islam M. Aminul , Pickering Amy J. , Roy Subarna , Fuhrmeister Erica R. , Ercumen Ayse , Harris Angela , Bishai Jason , Schwab Kellogg J. 
Published: December 2014

ABSTRACT

The increased awareness of the role of environmental matrices in enteric disease transmission has resulted in the need for rapid, field-based methods for fecal indicator bacteria and pathogen detection. Evidence of the specificity of β-glucuronidase-based assays for detection of
Escherichia coli
from environmental matrices relevant to enteric pathogen transmission in developing countries, such as hands, soils, and surfaces, is limited. In this study, we quantify the false-positive rate of a β-glucuronidase-based
E. coli
detection assay (Colilert) for two environmental reservoirs in Bangladeshi households (hands and soils) and three fecal composite sources (cattle, chicken, and humans). We investigate whether or not the isolation source of
E. coli
influences phenotypic and genotypic characteristics. Phenotypic characteristics include results of biochemical assays provided by the API-20E test; genotypic characteristics include the Clermont phylogroup and the presence of enteric and/or environmental indicator genes
sfmH
,
rfaI
, and
fucK
. Our findings demonstrate no statistically significant difference in the false-positive rate of Colilert for environmental compared to enteric samples.
E. coli
isolates from all source types are genetically diverse, representing six of the seven phylogroups, and there is no difference in relative frequency of phylogroups between enteric and environmental samples. We conclude that Colilert, and likely other β-glucuronidase-based assays, is appropriate for detection of
E. coli
on hands and in soils with low false-positive rates. Furthermore,
E. coli
isolated from hands and soils in Bangladeshi households are diverse and indistinguishable from cattle, chicken, and human fecal isolates, using traditional biochemical assays and phylogrouping.
A Vector System for ABC Transporter-Mediated Secretion and Purification of Recombinant Proteins in Pseudomonas Species
Authors: Ryu Jaewook , Lee Ukjin , Park Jiye , Yoo Do-Hyun , Ahn Jung Hoon 
Published: December 2014

ABSTRACT

Pseudomonas fluorescens
is an efficient platform for recombinant protein production.
P. fluorescens
has an ABC transporter secreting endogenous thermostable lipase (TliA) and protease, which can be exploited to transport recombinant proteins across the cell membrane. In this study, the expression vector pDART was constructed by inserting
tliDEF
, genes encoding the ABC transporter, along with the construct of the lipase ABC transporter recognition domain (LARD), into pDSK519, a widely used shuttle vector. When the gene for the target protein was inserted into the vector, the C-terminally fused LARD allowed it to be secreted through the ABC transporter into the extracellular medium. After secretion of the fused target protein, the LARD containing a hydrophobic C terminus enabled its purification through hydrophobic interaction chromatography (HIC) using a methyl-Sepharose column. Alkaline phosphatase (AP) and green fluorescent protein (GFP) were used to validate the expression, export, and purification of target proteins by the pDART system. Both proteins were secreted into the extracellular medium in
P. fluorescens
. In particular, AP was secreted in several
Pseudomonas
species with its enzymatic activity in extracellular media. Furthermore, purification of the target protein using HIC yielded some degree of AP and GFP purification, where AP was purified to almost a single product. The pDART system will provide greater convenience for the secretory production and purification of recombinant proteins in Gram-negative bacteria, such as
Pseudomonas
species.
Field and Experimental Evidence of Vibrio parahaemolyticus as the Causative Agent of Acute Hepatopancreatic Necrosis Disease of Cultured Shrimp (Litopenaeus vannamei) in Northwestern Mexico
Authors: Soto-Rodriguez Sonia A. , Gomez-Gil Bruno , Lozano-Olvera Rodolfo , Betancourt-Lozano Miguel , Morales-Covarrubias Maria Soledad 
Published: December 2014

ABSTRACT

Moribund shrimp affected by acute hepatopancreatic necrosis disease (AHPND) from farms in northwestern Mexico were sampled for bacteriological and histological analysis. Bacterial isolates were molecularly identified as
Vibrio parahaemolyticus
by the presence of the
tlh
gene. The
tdh
-negative,
trh
-negative, and
tlh
-positive
V. parahaemolyticus
strains were further characterized by repetitive extragenic palindromic element-PCR (rep-PCR), and primers AP1, AP2, AP3, and AP and an ems2 IQ2000 detection kit (GeneReach, Taiwan) were used in the diagnostic tests for AHPND. The
V. parahaemolyticus
strains were used in immersion challenges with shrimp, and farmed and challenged shrimp presented the same clinical and pathological symptoms: lethargy, empty gut, pale and aqueous hepatopancreas, and expanded chromatophores. Using histological analysis and bacterial density count, three stages of AHNPD (initial, acute, and terminal) were identified in the affected shrimp. The pathognomonic lesions indicating severe desquamation of tubular epithelial cells of the hepatopancreas were observed in both challenged and pond-infected shrimp. The results showed that different
V. parahaemolyticus
strains have different virulences; some of the less virulent strains do not induce 100% mortality, and mortality rates also rise more slowly than they do for the more virulent strains. The virulence of
V. parahaemolyticus
strains was dose dependent, where the threshold infective density was 10
4
CFU ml
−1
; below that density, no mortality was observed. The AP3 primer set had the best sensitivity and specificity. Field and experimental results showed that the
V. parahaemolyticus
strain that causes AHPND acts as a primary pathogen for shrimp in Mexico compared with the
V. parahaemolyticus
strains reported to date.