bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combined Heat and Power Generation for a Small Municipality for District Heating Purposes, Using Different Fuels
Authors: Tourlidakis A. , Malkogianni A. , Karlopoulos E. 
Published: November 2013

Environmental concerns related to climate change are forcing many countries to consider implementing cogeneration of heat and power with centralized heating systems (i.e. district heating networks) which are becoming increasingly widespread in many countries. Combined heat and power (CHP) or cogeneration is the simultaneous production of electricity and useful thermal energy. The big interest this technology is receiving, both globally and locally, has its reason in the chance of reducing fuel consumption by enhancing energy production processes. The considerable amount of waste heat associated to traditional power stations is transformed into useful heat, which can be sent through the district network to houses and buildings for heating or cooling. Considering the pollution district heating reduce local pollutants such as dust, sulphur dioxide and nitrogen oxides by replacing exhausts from individual boilers. In addition to the reduced use of fuels, far more effective pollution prevention and control measures can be taken in central production facilities.
The purpose of this paper is to present the results of the investigation for the installation of a small-scale CHP plant for District Heating purposes in a small municipality in Northern Greece.
Initially the heat and electricity demands were estimated based on a combination of historical consumption data, the construction features of the buildings and the weather conditions in the region.
A pipe network was designed and sized appropriately and the utilization of a CHP plant was studied.
Additionally, a number of various fuel options were considered such as natural gas, oil, pulverised coal and biomass from crop and forest residues, and also animal waste. The availability in biomass in the local region was estimated and it was found that it could cover a small percentage of approximately 5% of the required heating power.
Finally, a techno-economic analysis was carried out and the CO2 reduction benefits were estimated.
Mechanical Behaviour and Microstructure Correlation in a Selective Laser Melted Superalloy
Authors: Brodin Håkan , Andersson Olov , Johansson Sten 
Published: November 2013

Selective laser melting (SLM), or, as the industry standard denotes the process, laser sintering, is an additive manufacturing process where metal powder is melted by a laser source layer-wise, forming a solid, dense metallic component. With the SLM process, near net shape components can be manufactured directly from a CAD model. The model is sliced into thin (max 100μm thick) layers. Powder is spread onto a metallic build platform and the powder is fused by a laser as dictated by the CAD model. The laser energy is intense enough to permit full melting (welding) of the particles to form solid metal. The process is repeated layer by layer until the part is complete.
A number of materials are available, including steel, aluminium, titanium and, in recent time, also superalloys. The material investigated in the current project is an alloy in agreement with the composition of Haynes International Hastelloy X, a solution strengthened superalloy typically used in large welded components exposed to high temperatures in oxidizing as well as reducing environments.
Microstructurally, the material is different from both a hot-rolled, as well as a cast material due to the manufacturing process. Since the SLM process involves laser melting of powder particles in the size range of <50μm, the structure resembles of a weld structure, however on a smaller scale. Due to the layer-by-layer build strategy, the material will exhibit anisotropy. Different heat treatment approaches can be adopted in order to homogenize the material and to minimize the effect of anisotropy. A stress relieve heat treatment was adopted and compared to the findings of the as manufactured SLM material.
The current project focuses on evaluating mechanical properties for a material manufactured by the SLM process and comparing to data for established manufacturing processes. For evaluation of the mechanical properties, low cycle fatigue testing and tensile testing has been performed. The microstructure and material deformation / cracking are evaluated by light optical microscopy and SEM, where electron backscatter diffraction is used. Due to the weld-like structure, the material will be transversely isotropic in the as-manufactured condition with one symmetry plane perpendicular to the build direction. Any direction perpendicular to the build direction tends to give increased strength compared to a direction parallel to the build direction if monotonic data are concerned. If fatigue properties are concerned, the anisotropy is also obvious. It is shown that the differences in behaviour can be coupled to microstructure.
Biot-Number Analogy for Design of Experiments in Turbine Cooling
Authors: Shih Tom I.-P. , Ramachandran Saiprashanth Gomatam 
Published: November 2013

Cooling of turbine components that come in contact with the hot gases strongly affects the turbine’s efficiency and service life. Designing effective and efficient cooling configurations requires detailed understanding on how geometry and operating conditions affect the way coolant cools the turbine materials. Experimental measurements that can reveal such information are difficult and costly to obtain because gas turbines operate at high temperatures (up to 2,000 K), high pressures (30+ bar), and the dimensions of many key features in the cooling configurations are small (millimeters or smaller). This paper presents a method that enables experiments to be conducted at near room temperatures, near atmospheric pressures, and using scaled-up geometries to reveal the temperature and heat-flux distributions within turbine materials as if the experiments were conducted under engine operating conditions. The method is demonstrated by performing conjugate CFD analyses on two test problems. Both problems involve a TBC-coated flat plate exposed to a hot-gas environment on one side and coolant flow on the other. In one problem, the heat transfer on the coolant side is enhanced by inclined ribs. In the other, it is enhanced by an array of pin fins.
This conjugate CFD study is based on 3-D steady RANS closed by the shear-stress-transport turbulence model for the fluid phase and the Fourier law for the solid phase. Results obtained show that, of the dimensionless parameters that are important to this problem, it is the Biot number that dominates. This study also shows that for two geometrically similar configurations, if the Biot number distributions on the corresponding hot-gas and coolant sides are nearly matched, then the magnitude and contours of the non-dimensional temperature and heat-flux distributions in the material will be nearly the same for the two configurations — even though the operating temperatures and pressures differ considerably. Thus, experimental measurements of temperature and heat-flux distributions within turbine materials that are obtained under ‘laboratory’ conditions could be scaled up to provide meaningful results under ‘engine’ relevant conditions.
Jet Engine Bird Ingestion Simulations: Comparison of Rotating to Non-Rotating Fan Blades
Authors: Howard Samuel A. , Hammer Jeremiah T. , Carney Kelly S. , Pereira J. Michael 
Published: November 2013

Bird strike events in commercial airliners are a fairly common occurrence. According to data collected by the US Department of Agriculture, over 80,000 bird strikes were reported in the period 1990–2007 in the US alone [1]. As a result, bird ingestion is an important factor in aero engine design and FAA certification. When it comes to bird impacts on engine fan blades, the FAA requires full-scale bird ingestion tests on an engine running at full speed to pass certification requirements. These rotating tests are complex and very expensive. To reduce development costs associated with new materials for fan blades, it is desirable to develop more cost effective testing procedures than full-scale rotating engine tests for material evaluation. An impact test on a non-rotating single blade that captures most of the salient physics of the rotating test would go a long way towards enabling large numbers of evaluative material screening tests.
NASA Glenn Research Center has been working to identify a static blade test procedure that would be effective at reproducing similar results as seen in rotating tests. The current effort compares analytical simulations of a bird strike on various non-rotating blades to a bird strike simulation on a rotating blade as a baseline case. Several different concepts for simulating the rotating loads on a non-rotating blade were analyzed with little success in duplicating the deformation results seen in the rotating case. The rotating blade behaves as if it were stiffer than the non-rotating blade resulting in less plastic deformation from a given bird impact. The key factor limiting the success of the non-rotating blade simulations is thought to be the effect of gyroscopics. Prior to this effort, it was anticipated the difficulty would be in matching the pre-stress in the blade due to centrifugal forces Additional work is needed to verify this assertion, and to determine if a static test procedure can simulate the gyroscopic effects in a suitable manner. This paper describes the various non-rotating concepts analyzed, and demonstrates the effect believed to be gyroscopic in nature on the results.
Distance‐preserving rigidity penalty on deformable image registration of multiple skeletal components in the neck
Authors: Kim Jihun , Matuszak Martha M. , Saitou Kazuhiro , Balter James M. 
Published: November 2013

Purpose:This study aims at developing and testing a novel rigidity penalty suitable for the deformable registration of tightly located skeletal components in the head and neck from planning computed tomography (CT) and daily cone‐beam CT (CBCT) scans of patients undergoing radiotherapy.Methods:The proposed rigidity penalty is designed to preserve intervoxel distances within each bony structure. This penalty was tested in the intensity‐based B‐spline deformable registration of five cervical vertebral bodies (C1–C5). The displacement vector fields (DVFs) from the registrations were compared to the DVFs generated by using rigid body motions of the cervical vertebrae, measured by the surface registration of vertebrae delineated on CT and CBCT images. Twenty five pairs of planning CT (reference) and treatment CBCTs (target) from five patients were aligned without and with the penalty. An existing penalty based on the orthonormality of the deformation gradient tensor was also tested and the effects of the penalties compared.Results:The mean magnitude of the maximum registration error with the proposed distance‐preserving penalty was (0.86, 1.12, 1.33) mm compared to (2.11, 2.49, 2.46) without penalty and (1.53, 1.64, 1.64) with the existing orthonormality‐based penalty. The improvement in the accuracy of the deformable image registration was also verified by comparing the Procrustes distance between the DVFs. With the proposed penalty, the average distance was 0.11 (σ 0.03 mm) which is smaller than 0.53 (0.1 mm) without penalty and 0.28 (0.04 mm) with the orthonormality‐based penalty.Conclusions:The accuracy of aligning multiple bony elements was improved by using the proposed distance‐preserving rigidity penalty. The voxel‐based statistical analysis of the registration error shows that the proposed penalty improved the integrity of the DVFs within the vertebral bodies.
Novel multimodality segmentation using level sets and Jensen‐Rényi divergence
Authors: Markel Daniel , Zaidi Habib , El Naqa Issam 
Published: November 2013

Purpose:Positron emission tomography (PET) is playing an increasing role in radiotherapy treatment planning. However, despite progress, robust algorithms for PET and multimodal image segmentation are still lacking, especially if the algorithm were extended to image‐guided and adaptive radiotherapy (IGART). This work presents a novel multimodality segmentation algorithm using the Jensen‐Rényi divergence (JRD) to evolve the geometric level set contour. The algorithm offers improved noise tolerance which is particularly applicable to segmentation of regions found in PET and cone‐beam computed tomography.Methods:A steepest gradient ascent optimization method is used in conjunction with the JRD and a level set active contour to iteratively evolve a contour to partition an image based on statistical divergence of the intensity histograms. The algorithm is evaluated using PET scans of pharyngolaryngeal squamous cell carcinoma with the corresponding histological reference. The multimodality extension of the algorithm is evaluated using 22 PET/CT scans of patients with lung carcinoma and a physical phantom scanned under varying image quality conditions.Results:The average concordance index (CI) of the JRD segmentation of the PET images was 0.56 with an average classification error of 65%. The segmentation of the lung carcinoma images had a maximum diameter relative error of 63%, 19.5%, and 14.8% when using CT, PET, and combined PET/CT images, respectively. The estimated maximal diameters of the gross tumor volume (GTV) showed a high correlation with the macroscopically determined maximal diameters, with aR2 value of 0.85 and 0.88 using the PET and PET/CT images, respectively. Results from the physical phantom show that the JRD is more robust to image noise compared to mutual information and region growing.Conclusions:The JRD has shown improved noise tolerance compared to mutual information for the purpose of PET image segmentation. Presented is a flexible framework for multimodal image segmentation that can incorporate a large number of inputs efficiently for IGART.
Four‐dimensional Monte Carlo simulations demonstrating how the extent of intensity‐modulation impacts motion effects in proton therapy lung treatments
Authors: Dowdell Stephen , Grassberger Clemens , Paganetti Harald 
Published: November 2013

Purpose:To compare motion effects in intensity modulated proton therapy (IMPT) lung treatments with different levels of intensity modulation.Methods:Spot scanning IMPT treatment plans were generated for ten lung cancer patients for 2.5Gy(RBE) and 12Gy(RBE) fractions and two distinct energy‐dependent spot sizes (σ ∼8–17 mm and ∼2–4 mm). IMPT plans were generated with the target homogeneity of each individual field restricted to <20% (IMPT20%). These plans were compared to full IMPT (IMPTfull), which had no restriction on the single field homogeneity. 4D Monte Carlo simulations were performed upon the patient 4DCT geometry, including deformable image registration and incorporating the detailed timing structure of the proton delivery system. Motion effects were quantified via comparison of the results of the 4D simulations (4D‐IMPT20%, 4D‐IMPTfull) with those of a 3D Monte Carlo simulation (3D‐IMPT20%, 3D‐IMPTfull) upon the planning CT using the equivalent uniform dose (EUD), V95 and D1‐D99. The effects in normal lung were quantified using mean lung dose (MLD) and V90%.Results:For 2.5Gy(RBE), the mean EUD for the large spot size is 99.9% ± 2.8% for 4D‐IMPT20% compared to 100.1% ± 2.9% for 4D‐IMPTfull. The corresponding values are 88.6% ± 8.7% (4D‐IMPT20%) and 91.0% ± 9.3% (4D‐IMPTfull) for the smaller spot size. The EUD value is higher in 69.7% of the considered deliveries for 4D‐IMPTfull. The V95 is also higher in 74.7% of the plans for 4D‐IMPTfull, implying that IMPTfull plans experience less underdose compared to IMPT20%. However, the target dose homogeneity is improved in the majority (67.8%) of plans for 4D‐IMPT20%. The higher EUD and V95 suggests that the degraded homogeneity in IMPTfull is actually due to the introduction of hot spots in the target volume, perhaps resulting from the sharper in‐target dose gradients. The greatest variations between the IMPT20% and IMPTfull deliveries are observed for patients with the largest motion amplitudes. These patients would likely be treated using gating or another motion mitigation technique, which was not the focus of this study.Conclusions:For the treatment parameters considered in this study, the differences between IMPTfull and IMPT20% are only likely to be clinically significant for patients with large (>20 mm) motion amplitudes.
Simultaneous Detection of Antibodies against Apx Toxins ApxI, ApxII, ApxIII, and ApxIV in Pigs with Known and Unknown Actinobacillus pleuropneumoniae Exposure Using a Multiplexing Liquid Array Platform
Authors: Giménez-Lirola Luis G. , Jiang Yong-Hou , Sun Dong , Hoang Hai , Yoon Kyoung-Jin , Halbur Patrick G. , Opriessnig Tanja 
Published: November 2013

ABSTRACTSurveillance for the presence ofActinobacillus pleuropneumoniaeinfection in a population plays a central role in controlling the disease. In this study, a 4-plex fluorescent microbead-based immunoassay (FMIA), developed for the simultaneous detection of IgG antibodies to repeat-in-toxin (RTX) toxins (ApxI, ApxII, ApxIII, and ApxIV) ofA. pleuropneumoniae, was evaluated using (i) blood serum samples from pigs experimentally infected with each of the 15 knownA. pleuropneumoniaeserovars or withActinobacillus suis, (ii) blood serum samples from pigs vaccinated with a bacterin containingA. pleuropneumoniaeserovar 1, 3, 5, or 7, and (iii) blood serum samples from pigs with an unknownA. pleuropneumoniaeexposure status. The results were compared to those obtained in a previous study where a dual-plate complement fixation test (CFT) and three commercially available enzyme-linked immunosorbent assays (ELISAs) were conducted on the same sample set. On samples from experimentally infected pigs, the 4-plex Apx FMIA detected specific seroconversion to Apx toxins as early as 7 days postinfection in a total of 29 pigs inoculated with 14 of the 15A. pleuropneumoniaeserovars. Seroconversion to ApxII and ApxIII was detected by FMIA in pigs inoculated withA. suis. The vaccinated pigs showed poor humoral responses against ApxI, ApxII, ApxIII, and ApxIV. In the field samples, the humoral response to ApxIV and theA. pleuropneumoniaeseroprevalence increased with age. This novel FMIA (with a sensitivity of 82.7% and a specificity of 100% for the anti-ApxIV antibody) was found to be more sensitive and accurate than current tests (sensitivities, 9.5 to 56%; specificity, 100%) and is potentially an improved tool for the surveillance of disease and for monitoring vaccination compliance.
Characterization of Escherichia coli Isolates from Hospital Inpatients or Outpatients with Urinary Tract Infection
Authors: Toval Francisco , Köhler Christian-Daniel , Vogel Ulrich , Wagenlehner Florian , Mellmann Alexander , Fruth Angelika , Schmidt M. Alexander , Karch Helge , Bielaszewska Martina , Dobrindt Ulrich 
Published: November 2013

ABSTRACT

Uropathogenic
Escherichia coli
(UPEC) is the most common cause of community- and hospital-acquired urinary tract infections (UTIs). Isolates from uncomplicated community-acquired UTIs express a variety of virulence traits that promote the efficient colonization of the urinary tract. In contrast, nosocomial UTIs can be caused by
E. coli
strains that differ in their virulence traits from the community-acquired UTI isolates. UPEC virulence markers are used to distinguish these facultative extraintestinal pathogens, which belong to the intestinal flora of many healthy individuals, from intestinal pathogenic
E. coli
(IPEC). IPEC is a diarrheagenic pathogen with a characteristic virulence gene set that is absent in UPEC. Here, we characterized 265 isolates from patients with UTIs during inpatient or outpatient treatment at a hospital regarding their phylogenies and IPEC or UPEC virulence traits. Interestingly, 28 of these isolates (10.6%) carried typical IPEC virulence genes that are characteristic of enteroaggregative
E. coli
(EAEC), Shiga toxin-producing
E. coli
(STEC), and atypical enteropathogenic
E. coli
(aEPEC), although IPEC is not considered a uropathogen. Twenty-three isolates harbored the
astA
gene coding for the EAEC heat-stable enterotoxin 1 (EAST1), and most of them carried virulence genes that are characteristic of UPEC and/or EAEC. Our results indicate that UPEC isolates from hospital patients differ from archetypal community-acquired isolates from uncomplicated UTIs by their spectrum of virulence traits. They represent a diverse group, including EAEC, as well as other IPEC pathotypes, which in addition contain typical UPEC virulence genes. The combination of typical extraintestinal pathogenic
E. coli
(ExPEC) and IPEC virulence determinants in some isolates demonstrates the marked genome plasticity of
E. coli
and calls for a reevaluation of the strict pathotype classification of EAEC.
Rapid Detection of Mycobacterium tuberculosis and Pyrazinamide Susceptibility Related topncAMutations in Sputum Specimens through an Integrated Gene-to-Protein Function Approach
Authors: Li Heng , Chen Jun , Zhou Man , Geng Xuelei , Yu Junping , Wang Weihua , Zhang Xian-En , Wei Hongping 
Published: November 2013

ABSTRACTTesting the pyrazinamide (PZA) susceptibility ofMycobacterium tuberculosisisolates is challenging. In a previous paper, we described the development of a rapid colorimetric test for the PZA susceptibility ofM. tuberculosisby a PCR-basedin vitro-synthesized-pyrazinamidase (PZase) assay. Here, we present an integrated approach to detectM. tuberculosisand PZA susceptibility directly from sputum specimens.M. tuberculosiswas detected first, using a novel long-fragment quantitative real-time PCR (LF-qPCR), which amplified a fragment containing the wholepncAgene. Then, the positive amplicons were sequenced to find mutations in thepncAgene. For new mutations not found in the Tuberculosis Drug Resistance Mutation Database (www.tbdreamdb.com), thein vitroPZase assay was used to test the PZA resistance. This approach could detectM. tuberculosiswithin 3 h with a detection limit of 7.8 copies/reaction and report the PZA susceptibility within 2 days. In an initial testing of 213 sputum specimens, the LF-qPCR found 53 positive samples with 92% sensitivity and 97% specificity compared to the culture test forM. tuberculosisdetection. DNA sequencing of the LF-qPCR amplicons revealed that 49 samples were PZA susceptible and 1 was PZA resistant. In the remaining 3 samples, with newpncAmutations, thein vitroPZase assay found that 1 was PZA susceptible and 2 were PZA resistant. This integrated approach provides a rapid, efficient, and relatively low-cost solution for detectingM. tuberculosisand PZA susceptibility without culture.
Fatal Empyema Thoracis Caused by Schizophyllum commune with Cross-Reactive Cryptococcal Antigenemia
Authors: Chan Jasper F. W. , Teng Jade L. L. , Li Iris W. S. , Wong Sally C. Y. , Leung Sally S. M. , Ho Po-On , To Kelvin K. W. , Lau Susanna K. P. , Woo Patrick C. Y. , Yuen Kwok-Yung 
Published: November 2013

ABSTRACT

We report a fatal case of
Schizophyllum commune
empyema thoracis with cross-reactive cryptococcal antigenemia.
In vitro
testing confirmed the ability of the fungus to cause a positive
c
ryptococcal
a
ntigen
l
atex
a
gglutination
s
ystem (CALAS) test result. Such a result may lead to delay in diagnosis and treatment, as most strains of
S. commune
are resistant to fluconazole.
A Fishy Tale: a Man with Empyema Caused by Streptococcus halichoeri
Authors: Foo Rui Min , Chan Douglas 
Published: November 2013

ABSTRACT

In 2004, veterinary laboratories in the United Kingdom reported a novel Lancefield group B streptococcus,
Streptococcus halichoeri
, in seals. We report a case of
Streptococcus halichoeri
causing postoperative empyema in a patient. A search of the literature revealed that this is the first case of
S. halichoeri
ever reported in humans.