bluuebunny/crossref_metadata_2025 huggingface dataset:
Perineural and intraneural cutaneous granulomas in granulomatous mycosis fungoides mimicking tuberculoid leprosy
Authors: Rodríguez Gerzain , Téllez Alejandra
Published: September 2016

Background

Histological similarities between granulomas and granulomatous mycosis fungoides (GMF) may lead to misdiagnoses of sarcoidosis or leprosy.

Methods

This report presents four patients with GMF in whom skin biopsies showed perineural and intraneural granulomas that were confused with tuberculoid leprosy granulomas.

Results

Patient 1 presented with erythematous plaques and bulky nodules. Biopsy findings suggested cutaneous sarcoidosis. Tumor resection showed granulomatous infiltrate extending to the fascia and skeletal muscle. Clinicopathological correlations permitted a diagnosis of GMF. Patient 2 presented with erythematous plaques. Skin biopsies had indicated sarcoidosis. Resection of a thigh nodule excluded leprosy, and GMF was diagnosed. Patient 3 presented with scaly, hyperpigmented plaques. Biopsy showed diffuse granulomatous inflammation with epithelioid and giant cells, abundant lymphocytes, and some eosinophils, and indicated GMF. Patient 4 presented with pruritic, erythematous plaques. Biopsy of an indurated mammary plaque initially indicated sarcoid granulomatous inflammation. Biopsy review suggested GMF.

Conclusions

This study highlights both the diagnosis of GMF, and granulomatous cutaneous nerve injury in GMF and its possible confusion with leprosy granulomas. The histological diagnosis of GMF includes: (i) a granulomatous infiltrate rich in giant cells, emperipolesis, histiocytic cells, and scattered eosinophils, which may reach the fascia and muscle; (ii) the absence of elastic fibers or their phagocytosis by giant cells; and (iii) lymphocytes that may show atypia and epidermotropism. Deep biopsies reveal GMF diagnostic changes and, in conjunction with clinicopathological correlations, exclude a diagnosis of leprosy and support one of GMF, thus facilitating its appropriate management.
Nursing care in multifunctional small group homes providing day, visiting and overnight services for older people living at home
Authors: Katahira Nobuko , Tsukasaki Keiko
Published: September 2016

Home care programs for older people have been developed around the world. Nurses are key to these programs. The aim of this study is to explore details of the nursing activities used in group homes to provide a basis for describing effective nursing practices in such facilities. A self‐administered questionnaire was sent to 240 randomly selected facilities throughout Japan in 2013. Responses indicated that the activities of nurses in managing the health of older people included determining the need for medical consultations, dealing with emergencies, and making arrangements for the use of flexible care services. Nursing activities were directly related to the percentage of older people in each facility with diagnoses such as dementia or heart disease. Nurses reported low general self‐efficacy for some of the more specialized nursing activities they performed. Nursing activities are performed with the aim of supporting older people with high health care needs to continue living at home; are tailored to the characteristics of residents and contribute to the provision of timely health examinations and flexible arrangement of services. Findings indicate that it might be advantageous to increase the nursing staffing at these facilities, to provide care guidelines and training opportunities to increase nurse self‐efficacy.
Combining lacewings and parasitoids for biological control of foxglove aphids in sweet pepper
Authors: Rocca M. , Messelink G. J.
Published: September 2016

The role of natural enemy diversity in biological pest control has been debated in many studies, and understanding how interactions amongst predators and parasitoids affect herbivore populations is crucial for pest management. In this study, we assessed the individual and combined use of two species of natural enemies, the parasitoid Aphidius ervi Haliday, and the predatory brown lacewing Micromus variegatus (Fabricius), on their shared prey, the foxglove aphid, Aulacorthum solani (Kaltenbach), on sweet pepper. We hypothesized that the presence of intraguild predation (IGP) and predator facilitation (through induced aphid dropping behaviour) might have both negative and positive effects on aphid control, respectively. Our greenhouse trial showed that overall, the greatest suppression of aphids occurred in the treatment with both the parasitoid and the lacewing. While the combination of lacewings and parasitoids significantly increased aphid control compared to the use of parasitoids alone, the effect was not significantly different to the treatment with only predators, although there was a clear trend of enhanced suppression. Thus, the combined effects of both species of natural enemies were between additive and non‐additive, suggesting that the combination is neither positive nor negative for aphid control. High levels of IGP, as proven in the laboratory, were probably compensated for by the strong aphid suppression provided by the lacewings, whether or not supplemented with some level of predator facilitation. For aphid management over a longer time scale, it might still be useful to combine lacewings and parasitoids to ensure stable and resilient aphid control.
First record of Tetramicra brevifilum in lumpfish (Cyclopterus lumpus, L.)
Authors: Scholz F , Fringuelli E , Bolton‐Warberg M , Marcos‐López M , Mitchell S , Prodhol P , Moffet D , Savage P , Murphy O'Sullivan S , O′Connor I , McCarthy E , Rodger H D
Published: September 2016

A microsporidian species with 98.3–98.4% nucleotide identity to Tetramicra brevifilum (Journal of Fish Diseases, 3, 1980, 495) was diagnosed in lumpfish (Cyclopterus lumpus, L.) broodstock held at a breeding and rearing facility in western Ireland. The fish were wild‐caught from the west coast of Ireland, and the first case was diagnosed one year after capture. Clinical signs included severe bloating, lethargy, exophthalmos, anorexia, white patches on the cornea and externally visible parasitic cysts on skin and fins. Necropsy revealed severe ascites, white nodules and vacuoles in all the internal organs and partial liquefaction of the skeletal muscle. On histological examination, microsporidian xenomas were observed in all internal organs, the skin, skeletal muscle, gills and the eyes. The microsporidian species was identified by molecular analysis and transmission electron microscopy. This is the first record of T. brevifilum infecting lumpfish, and the disease is considered to be of potential significance to the rising aquaculture industry of this species.
Comparison of quartz crystallographic preferred orientations identified with optical fabric analysis, electron backscatter and neutron diffraction techniques
Authors: HUNTER N.J.R. , WILSON C.J.L. , LUZIN V.
Published: September 2016

Three techniques are used to measure crystallographic preferred orientations (CPO) in a naturally deformed quartz mylonite: transmitted light cross‐polarized microscopy using an automated fabric analyser, electron backscatter diffraction (EBSD) and neutron diffraction. Pole figure densities attributable to crystal‐plastic deformation are variably recognizable across the techniques, particularly between fabric analyser and diffraction instruments. Although fabric analyser techniques offer rapid acquisition with minimal sample preparation, difficulties may exist when gathering orientation data parallel with the incident beam. Overall, we have found that EBSD and fabric analyser techniques are best suited for studying CPO distributions at the grain scale, where individual orientations can be linked to their source grain or nearest neighbours. Neutron diffraction serves as the best qualitative and quantitative means of estimating the bulk CPO, due to its three‐dimensional data acquisition, greater sample area coverage, and larger sample size. However, a number of sampling methods can be applied to FA and EBSD data to make similar approximations.
Progression of alpha‐synuclein pathology in multiple system atrophy of the cerebellar type
Authors: Brettschneider J. , Irwin D. J. , Boluda S. , Byrne M. D. , Fang L. , Lee E. B. , Robinson J. L. , Suh E. , Van Deerlin V. M. , Toledo J. B. , Grossman M. , Hurtig H. , Dengler R. , Petri S. , Lee V. M.‐Y. , Trojanowski J. Q.
Published: September 2016

Aims

The aim of this study was to identify early foci of α‐synuclein (α‐syn pathology) accumulation, subsequent progression and neurodegeneration in multiple system atrophy of the cerebellar type (MSA‐C).

Methods

We analysed 70‐μm‐thick sections of 10 cases with MSA‐C and 24 normal controls.

Results

MSA‐C cases with the lowest burden of pathology showed α‐syn glial cytoplasmic inclusions (GCIs) in the cerebellum as well as in medullary and pontine cerebellar projections. Cerebellar pathology was highly selective and severely involved subcortical white matter, whereas deep white matter and granular layer were only mildly affected and the molecular layer was spared. Loss of Purkinje cells increased with disease duration and was associated with neuronal and axonal abnormalities. Neocortex, basal ganglia and spinal cord became consecutively involved with the increasing burden of α‐syn pathology, followed by hippocampus, amygdala, and, finally, the visual cortex. GCIs were associated with myelinated axons, and the severity of GCIs correlated with demyelination.

Conclusions

Our findings indicate that cerebellar subcortical white matter and cerebellar brainstem projections are likely the earliest foci of α‐syn pathology in MSA‐C, followed by involvement of more widespread regions of the central nervous system and neurodegeneration with disease progression.
Is There a Difference in Tachycardia Cycle Length during SVT in Children with AVRT and AVNRT?
Authors: MILLS MARCOS F. , MOTONAGA KARA S. , TRELA ANTHONY , DUBIN ANNE M. , AVASARALA KISHOR , CERESNAK SCOTT R.
Published: September 2016

Background

There are limited adult data suggesting the tachycardia cycle length (TCL) of atrioventricular reentry tachycardia (AVRT) is shorter than atrioventricular nodal reentry tachycardia (AVNRT), though little data exist in children. We sought to determine if there is a difference in TCL between AVRT and AVNRT in children.

Methods

A single‐center retrospective review of children with supraventricular tachycardia (SVT) from 2000 to 2015 was performed. Inclusion criteria: Age ≤ 18 years, invasive electrophysiology study (EPS) confirming AVRT or AVNRT. Exclusion criteria: Atypical AVNRT, congenital heart disease, antiarrhythmic medication use at time of EPS. Data were compared between patients with AVRT and AVNRT via t‐test, χ2 test, and linear regression.

Results

A total of 835 patients were included (12 ± 4 years, 52 ± 31 kg, TCL 321 ± 55 ms), 539 (65%) with AVRT (270 Wolff‐Parkinson‐White, 269 concealed pathways) and 296 (35%) with AVNRT. Patients with AVRT were younger (11.7 ± 4.1 years vs 13.0 ± 3.6 years, P < 0.001) and smaller (49 ± 22 kg vs 57 ± 43 kg, P < 0.001). In the baseline state, the TCL was shorter in AVRT than AVRNT (329 ± 51 ms vs 340 ± 60 ms, P = 0.04). In patients requiring isoproterenol to induce SVT, there was no difference in TCL (290 ± 49 ms vs 297 ± 49 ms, P = 0.26). When controlling for age, there was no difference in TCL between AVRT and AVNRT at baseline or on isoproterenol. The regression equation for TCL in the baseline state was TCL = 290 + 4 (age), indicating the TCL will increase by 4 ms above a baseline of 290 ms for each year of life.

Conclusions

When controlling for age, there is no difference in the TCL between AVRT and AVNRT in children. Age, not tachycardia mechanism, is the most significant factor in predicting TCL.
Genomic regions, cellular components and gene regulatory basis underlying pod length variations in cowpea (V. unguiculata L. Walp)
Authors: Xu Pei , Wu Xinyi , Muñoz‐Amatriaín María , Wang Baogen , Wu Xiaohua , Hu Yaowen , Huynh Bao‐Lam , Close Timothy J. , Roberts Philip A. , Zhou Wen , Lu Zhongfu , Li Guojing
Published: September 2016

Cowpea (V. unguiculata L. Walp) is a climate resilient legume crop important for food security. Cultivated cowpea (V. unguiculata L) generally comprises the bushy, short‐podded grain cowpea dominant in Africa and the climbing, long‐podded vegetable cowpea popular in Asia. How selection has contributed to the diversification of the two types of cowpea remains largely unknown. In the current study, a novel genotyping assay for over 50 000 SNPs was employed to delineate genomic regions governing pod length. Major, minor and epistatic QTLs were identified through QTL mapping. Seventy‐two SNPs associated with pod length were detected by genome‐wide association studies (GWAS). Population stratification analysis revealed subdivision among a cowpea germplasm collection consisting of 299 accessions, which is consistent with pod length groups. Genomic scan for selective signals suggested that domestication of vegetable cowpea was accompanied by selection of multiple traits including pod length, while the further improvement process was featured by selection of pod length primarily. Pod growth kinetics assay demonstrated that more durable cell proliferation rather than cell elongation or enlargement was the main reason for longer pods. Transcriptomic analysis suggested the involvement of sugar, gibberellin and nutritional signalling in regulation of pod length. This study establishes the basis for map‐based cloning of pod length genes in cowpea and for marker‐assisted selection of this trait in breeding programmes.
A Case of Cutaneous Inflammatory Myofibroblastic Tumor
Authors: de Menezes Sara , Mar Adrian , Dowling John , Wright Annaliesa
Published: September 2016

Inflammatory myofibroblastic tumor (IMT) rarely occurs as a primary cutaneous lesion. We report a case of cutaneous IMT in an 8‐year‐old girl presenting with an ulcerated nodule on the cheek. Although cutaneous IMT poses a diagnostic challenge because of its rarity, excision of the lesion is likely to be curative.
Sudden Onset of Papular Elastorrhexis After Immunologic Recovery in a Boy with Human Immunodeficiency Virus
Authors: Rodríguez‐Lomba Enrique , Molina‐López Irene , Parra‐Blanco Verónica , Suárez‐Fernández Ricardo , Campos‐Domínguez Minia
Published: September 2016

Papular elastorrhexis (PE) is an uncommon elastic tissue disorder clinically characterized by the onset of asymptomatic flesh‐colored to whitish papules over the trunk and upper limbs in children. Its etiology remains unknown, although isolated familial cases have suggested that acquired and inherited forms of the disease may exist. We present the case of a 13‐year‐old boy with human immunodeficiency virus who presented with such lesions after immunological recovery from very low CD4+ counts after introducing highly active antiretroviral therapy. Because neutrophils and macrophages are implicated in elastin metabolism and degradation pathways, immune dysregulation might be another etiologic factor to be considered in this rare disease.
Annular Lichenoid Dermatitis of Youth: A Chronic Case Managed Using Pimecrolimus
Authors: Malachowski Stephen J. , Creasey Mackenzie , Kinkley Nancy , Heaphy Michael R.
Published: September 2016

Annular lichenoid dermatitis of youth, first described in 2003, is a rare and occasionally chronic skin disease. We report a case of annular lichenoid dermatitis of youth relapsing over the course of 5 years successfully treated and maintained with topical pimecrolimus cream.
Defining Environmental Justice Communities for Regulatory Enforcement: Implications from a Block‐Group‐Level Analysis of New York State
Authors: Liang Jiaqi
Published: September 2016

The absence of a clear definition of environmental justice areas has been cited as one of the U.S. Environmental Protection Agency's major deficiencies in managing federal environmental justice programs. Several states have explicitly defined potential environmental justice areas and integrated targeted efforts into the policy‐making process. At the block‐group level, this study evaluates the effects of New York State's environmental justice policy, which defines communities of concern in terms of demographic and socioeconomic characteristics as well as mandates supplemental regulatory enforcement activities for these neighborhoods, on the agency's policy implementation practices under the Clean Air Act and Clean Water Act. The empirical findings suggest that there is inconclusive evidence regarding race/ethnicity‐ and class‐based environmental inequity. Also, the state's policy intervention is not universally effective. Moreover, task environments of a given community are a consistent determinant of the agency's regulatory compliance monitoring and assurance activities. This study then derives broader implications regarding the adoption of a policy instrument that defines and screens potential environmental justice communities.
T1-T2 WEIGHTED MR IMAGE COMPOSITION AND CATALOGUING OF BRAIN TUMOR USING REGULARIZED LOGISTIC REGRESSION
Authors: Aju D. , Rajkumar R.
Published: September 2016

In medical diagnosis, the functional and structural information of the brain as well as the impending abnormal tissues is very crucial and important with an MR image. A collective CAD system that detects and classifies the brain tumor by exploiting the structural information is presented. Magnetic Resonance Imaging (MRI) T1-weighted and T2-weighted images provides suitable variation of contrast between the different soft tissues of the brain which is suitable for detecting the brain tumor. Both the Magnetic Resonance (MR) image sequences are composited using the alpha blending technique. The tumor area in the MR images will be segmented using the Enhanced Watershed Segmentation (EWATS) algorithm. The feature extraction is a means of signifying the raw image data in its abridged form to ease the classification in a better way. An expert classification assistant is tried out to help the physicians to classify the detected MRI brain tumor in an efficient manner. The proposed method uses the Regularized Logistic Regression (RLR) for the efficient cataloguing of brain tumor in which it achieves an effective accuracy rate of 96%, specificity rate of 86% and sensitivity rate of 97%.
FAULT DIAGNOSIS OF THREE-PHASE INDUCTION MOTORS BASED ON VIBRATION AND ELECTRICAL CURRENT SIGNALS
Authors: Yousefi Rozbeh , Yusof Rubiyah , Arfa Reza
Published: September 2016

Induction motors (IM) as a critical component of many industrial processes are subjected to issues such as aging motors, high reliability requirements, and cost competitiveness. Therefore, many research efforts have been focused on fault detection in IMs. The main specification of this paper involves fault detection of three phase IMs using vibration and electrical current setup. This paper compares the results obtained by vibration and electrical current setup in order to a better understanding of fault detection setups’ operation in induction machines. The experimentation was performed on two faulty and one healthy squirrel cage motor. A number of data was captured through the labVIEW software. Principal Component Analysis (PCA) was employed for feature extraction to classify the faults of IMs. Most vibration hardware systems are relatively costly and difficult to set up, but they resulted in significantly higher accurate and classified data in comparison to the results of current setup.
DESIGN STANDARD IN HEALTH CARE TO FOLLOW OR NOT? AN INSIGHT FROM CLINICAL PATHWAY
Authors: Hussien Al-Ashwal Rania , Supriyanto Eko , Andriantoro Hananto
Published: September 2016

Clinical pathway is a management tool utilized in hospitals in order to reduce variation in medical care as well as control health quality. Poor adherence to the clinical pathway documents most probably leads to deficiency in quality of care. This paper presents the result of an investigation for the role of clinical pathway document component (design) on the use of the clinical pathway tool in practice. We checked the content of three clinical pathway designs using the Integrated Care Pathway Appraisal Tool (ICPAT). Negative correlation between the compliance to ICPAT indicators and the completeness of third clinical pathway design has been obtained. Standard criteria in designing clinical pathway shows discrepancy which might be due to reluctances among the users to follow the lengthy procedure. In conclusion, user’s preferences need to be considered for more practical use of clinical pathway beside the standard documentation perfection in order to achieve its objectives.
EXPERIMENTAL AND NUMERICAL INVESTIGATION OF HEAT TRANSFER AUGMENTATION USING AL2O3-ETHYLENE GLYCOL NANOFLUIDS UNDER TURBULENT FLOWS IN A FLAT TUBE
Authors: Abdolbaqi M. Kh. , Che Sidik Nor Azwadi , Muhammad Yazid Muhammad Noor Afiq Witri , Mamat Rizalman , Azmi W. H. , M. Kh. Hind
Published: September 2016

A study of computational fluid dynamics has been conducted to study the characteristics of the heat transfer and friction factor of Al2O3/Ethylene glycol-water nanofluid flowing inside flat tube. The three dimensional realizable k–e turbulent model with an enhanced wall treatment was utilized. The evaluation of the overall performance of the tested tube was predicated on the thermo-hydrodynamic performance index. The obtained results showed that the difference in behaviour depending on the parameter that has been selected to compare the nanofluid with the base fluid. In addition, the friction factor and the heat transfer coefficient increases with an increase of the nanoparticles volume concentration at the same Reynolds number. The penalty of pressure drop is negligible with an increase of the volume concentration of nanoparticles. Conventional correlations that have been used in turbulent flow regime to predict average heat transfer and friction factor are Dittus-Boelter and Blasius correlations, for tubes are also valid for the tested nanofluids which consider that the nanofluids have a homogeneous fluid behaviour.
THE EFFECTS OF THE DIE HALF ANGLE OF TAPER DIE ON PLANE STRAIN EXTRUSION
Authors: Zuan A. M. S. , Yong S. Y. , Nurul M. A. , Syahrullail S. , Rahim E. A.
Published: September 2016

In this research, a study of the effect of a die half angle on the extrusion process has been performed. The experiments were conducted at room temperature around 27 °C. Two types of taper die with different die half angles (45° and 60°) were prepared. The test lubricants used were paraffinic mineral oil VG460 and Refined, Bleached and Deodorized (RBD) Palm stearin. The material of the workpiece (billet) was annealed with A1100 aluminium. The experimental results were focused on the extrusion load, tool and workpiece surface roughness and plastic deformation of the workpiece. The resultant relative velocity was calculated using a visioplasticity method. The results shows that a taper angle of 60° recorded higher resultant relative velocity with a lower extrusion load and surface roughness compare to the taper angle of 45°. The comparison study between Paraffinic Mineral Oil and RBD Palm Stearin shows no significant effect in both taper angles tested.
DEVELOPMENT OF PALM BIOMASS BRIQUETTES WITH POLYETHYLENE PLASTIC WASTE ADDITION
Authors: Mohd Faizal Hasan , M. Nazri M. Shafiq , Rahman Md. Mizanur , Syahrullail S. , Latiff Z. A.
Published: September 2016

High global energy demand scenario has driven towards transformation from sole dependence on fossil fuels to utilization of inexhaustible renewable energy sources such as hydro, biomass, solar and wind. Renewable energy sources are abundant in Malaysia, especially palm biomass residues that are produced during the oil extraction process of fresh fruit bunch. Therefore, it is inevitable to harness these bioenergy sources, in order to prevent waste accumulation at adjacent to palm mills. Briquetting of palm biomass such as empty fruit bunch (EFB) with polyethylene (PE) plastics waste addition is expected not only could maximize the utilization of energy resources, but also could become as a potential solution for residue and municipal plastics waste disposal. In the present study, the physical and combustion properties of palm biomass briquettes that contain novel mixture of pulverized EFB and PE plastics waste were investigated experimentally. The briquettes were produced with different mixing ratio of EFB and PE plastics (weight ratios of 95:5, 90:10 and 85:15), under various heating temperatures (130-190 ) and at constant compaction pressure of 7 MPa. Based on the results, it can be said that heating temperature plays a significant role in affecting physical properties such as relaxed density and compressive strength. The values of relaxed density and compressive strength are within the range of 1100 to 1300 kg/m3 and 0.8 to 1.2 MPa, respectively. Meanwhile, mixing ratio does affect relaxed density and gross calorific value. All values of gross calorific (17900 to 21000 kJ/kg) and moisture content (7% to 9%) are found to fulfill the requirement for commercialization as stated by DIN51731 (gross calorific value>17500 kJ/kg and moisture content<10%). Even though the values of ash content (3% to 4%) exceed the limitation as stated by the standard (<0.7%), it is still considered very competitive if compared to the commonly used local briquette that contains mesocarp fibre and shell (5.8%). Finally, it can be concluded that the best quality of briquette can be achieved when highest composition of PE plastics (weight percentage of 15%) is used and the briquetting process is performed at the highest temperature (190 ).
A Mathematical Model and Inflow Control Effect Analysis of Inflow Control Devices Completed Horizontal Well
Authors: Liu Yongge , Liu Huiqing , Hou Jian , Wang Qing , Dong Kai
Published: September 2016

The main purpose of this paper is to analyze and compare the influence of nozzle size, uneven gravel packing, packer leakage, and dynamic production process on the inflow control effect. First, a new mathematical model of Inflow control devices (ICDs) completed horizontal well is proposed which has two new features. One feature is that the annulus between the sand control screen and the formation is considered. Therefore, the influence of uneven gravel packing can be simulated by adjusting the permeability distribution along the annulus. The other feature is that it accounts for packer leakage by introducing a new parameter named “leakage factor” into the model. Then, the inflow control efficiency is defined and used to quantitatively characterize the inflow control effect, and the influences of nozzle size, uneven gravel packing, packer leakage, and dynamic production process on inflow control efficiency are analyzed. The results show that the nozzle size and packer leakage have the biggest influence on the inflow control efficiency, and the influence of gravel packing is negligible unless the permeability of the packed gravel along the wellbore is extremely heterogeneous.
Influence of Gravitational Modulation on Natural Convection in a Horizontal Porous Annulus
Authors: Belabid Jabrane , Allali Karam
Published: September 2016

The influence of gravitational modulation on natural convection in a horizontal porous annulus is investigated in this paper. The mathematical model describing the phenomenon consists of the heat equation coupled by the hydrodynamics equations under the Boussinesq approximation. The derived system of equations with the stream function–temperature formulation is obtained and solved numerically using the alternating direction implicit method. It is shown that the convective stability of the fluid can be gained for small amplitudes of the vibration, while it will be lost for large ones. It was also observed that increasing the frequency has a destabilizing effect.
Unsteady Adjoint of Pressure Loss for a Fundamental Transonic Turbine Vane
Authors: Talnikar Chaitanya , Wang Qiqi , Laskowski Gregory M.
Published: September 2016

High-fidelity simulations, e.g., large eddy simulation (LES), are often needed for accurately predicting pressure losses due to wake mixing and boundary layer development in turbomachinery applications. An unsteady adjoint of high-fidelity simulations is useful for design optimization in such aerodynamic applications. In this paper, we present unsteady adjoint solutions using a large eddy simulation model for an inlet guide vane from von Karman Institute (VKI) using aerothermal objectives. The unsteady adjoint method is effective in capturing the gradient for a short time interval aerothermal objective, whereas the method provides diverging gradients for long time-averaged thermal objectives. As the boundary layer on the suction side near the trailing edge of the vane is turbulent, it poses a challenge for the adjoint solver. The chaotic dynamics cause the adjoint solution to diverge exponentially from the trailing edge region when solved backward in time. This results in the corruption of the sensitivities obtained from the adjoint solutions. An energy analysis of the unsteady compressible Navier–Stokes adjoint equations indicates that adding artificial viscosity to the adjoint equations can dissipate the adjoint energy while potentially maintaining the accuracy of the adjoint sensitivities. Analyzing the growth term of the adjoint energy provides a metric for identifying the regions in the flow where the adjoint term is diverging. Results for the vane obtained from simulations performed on the Titan supercomputer are demonstrated.
Effects of Tip Shroud Geometries on Low-Pressure Turbine Performance
Authors: Le Guyader Sébastien , Démolis Jacques , Munoz Julien
Published: September 2016

In low-pressure turbine stages, it is typical to have tip shrouds on the rotor blades to achieve high efficiency and offer improve mechanical dynamics. It is commonly known that the leakage flow across the shroud clearance contributes significantly to the losses. Generally the losses can be separated into losses from the leakage flow itself and losses caused by the interaction with the main flow downstream of the airfoil rows. In this paper, two types of tip shrouds are evaluated: a classical one used generally in low-speed low-pressure turbine and a contoured one used to decrease the mass at the blade tip. Despite limiting the bending stress of the rotor blade, the contoured tip shroud generates complex 3D flows at the rotor exit which may lead to a lower efficiency. These studies are numerically performed on a two stage low-pressure turbine with tip shroud on both rotors. The 3D RANS Navier-Stokes computations use an overset grid technique (Chimera) to accommodate complex geometries in a structured grid flow solver. Discussions are focused on the 3D flows near the leakage flow for all the configurations. A detailed discussion centers on the comparison between 1D-correlation and 3D results.
Numerical Study of the Reynolds Number Effect on the Centrifugal Compressor Performance and Losses
Authors: Tiainen Jonna , Jaatinen-Värri Ahti , Grönman Aki , Backman Jari
Published: September 2016

The efficiency is reduced in very small centrifugal compressors due to low Reynolds numbers. In the past, the effect of the Reynolds number on centrifugal compressor performance has been studied experimentally, and empirical correction equations for the efficiency have been derived based on those results. There is a lack of numerical investigations into the effect of the Reynolds number on centrifugal compressor performance and losses. This paper aims to compare the numerical results to the efficiencies predicted by the correction equations found in the literature. The loss generation in the impeller blade passages is also studied in order to find out which loss production mechanism has the most potential to be reduced or eliminated.

The effect of the Reynolds number on compressor performance is investigated in the chord Reynolds number range varying from 0.8 · 105 to 17 · 105 by simulating numerically the original compressors and downscaled ones. The numerical results are validated against experimental data and the results are compared with the efficiency correction equations used in the literature. The results indicate that the performance of the downscaled compressors follow quite precisely the most recently published correction equation. The results also show that the increased losses in low-Reynolds-number compressors are caused both by the relatively increased boundary layer thickness and by the shear stress resulting from the increased vorticity.
On the Unsteady Interaction Between the Leakage and the Main Passage Flow in a High Pressure Turbine Rig: CFD URANS Investigations and Comparison With the Rig Test Data
Authors: Zamboni Giulio , Adami Paolo
Published: September 2016

The flow path of modern turbine stages is highly influenced by the interaction of the main passage flow with the secondary leakages used for sealing purposes. The interaction between these two flows significantly influences the topology of the overturning passage secondary flow and therefore with the performance of the turbine itself. During the aerodynamic design phase, this complex interaction is usually assessed using RANS and URANS CFD calculations.

This paper reports on the use of CFD calculations to predict the complex fluid dynamic interaction between the leakage at the inner platform upstream of a single stage HPT blade and the generation of the secondary overturning passage flow within the aerofoil. Rig test data are presented for a direct comparison with the CFD considering two different rim sealing geometric configurations.

The first aim of this paper is to show how the prediction of similar complex flows can be addressed to quantify the performance improvement and what results can be expected when using industrial mature simulation technology based on RANS/URANS CFD. The second objective is to support the understanding of accuracy improvements requirements and limitations still observed when comparing these flow path predictions with rig test data.

This work shows that despite the ability to capture trends, the details of these complex flow interactions still represent a challenge for the state of the art RANS and URANS solvers used in the design of the gas path of the HPT turbine stages. The understanding of the accuracy in prediction capability through the comparison with rig test data is not only essential to support present design work, but also for the developments and assessment of the next generation of modelling capabilities.
Effects of Double-Leakage Tip Clearance Flow on the Performance of a Compressor Stage With a Large Rotor Tip Gap
Authors: Hah Chunill
Published: September 2016

Effects of a large rotor tip gap on the performance of a one and half stage axial compressor are investigated in detail with a numerical simulation based on LES and available PIV data. The current paper studies the main flow physics, including why and how the loss generation is increased with the large rotor tip gap. The present study reveals that when the tip gap becomes large, tip clearance fluid goes over the tip clearance core vortex and enters into the next blade’s tip gap, which is called double-leakage tip clearance flow. As the tip clearance flow enters into the adjacent blade’s tip gap, a vortex rope with a lower pressure core is generated. This vortex rope breaks up the tip clearance core vortex of the adjacent blade, resulting in a large additional mixing. This double-leakage tip clearance flow occurs at all operating conditions, from design flow to near stall condition, with the large tip gap for the current compressor stage. The double-leakage tip clearance flow, its interaction with the tip clearance core vortex of the adjacent blade, and the resulting large mixing loss are the main flow mechanism of the large rotor tip gap in the compressor. When the tip clearance is smaller, flow near the end wall follows more closely with the main passage flow and this double-leakage tip clearance flow does not happen near the design flow condition for the current compressor stage. When the compressor with a large tip gap operates at near stall operation, a strong vortex rope is generated near the leading edge due to the double-leakage flow. Part of this vortex separates from the path of the tip clearance core vortex and travels from the suction side of the blade toward the pressure side of the blade. This vortex is generated periodically at near stall operation with a large tip gap. As the vortex travels from the suction side to the pressure side of the blade, a large fluctuation of local pressure forces blade vibration. Non-synchronous blade vibration occurs due to this vortex as the frequency of this vortex generation is not the same as the rotor. The present investigation confirms that this vortex is a part of separated tip clearance vortex, which is caused by the double-leakage tip clearance flow.
Energy Analysis of Recuperated Gas Turbine Cycles With Mist Blade Cooling
Authors: Elwekeel Fifi N. M. , Abdala Antar M. M. , Zheng Qun
Published: September 2016

The present work investigates the effects of mist injection in turbine blade cooling line and the investigation parameters on the performance parameters. The investigation parameters are ambient temperature, ambient relative humidity, and compressor pressure ratio and turbine inlet temperature. The performance parameters are coolant ratio, plant efficiency, heat regeneration rate and specific fuel consumption. This study is conducted on simple recuperated cycle (SRC), recuperated cycle with closed loop cooling (RCCLC) and recuperated cycle with film cooling (RCFC). The results show that by mist, the compressor pressure ratio can be extended to 11 to achieve optimum efficiency. The plant efficiency of RCCLC increases by 2.5% than that for SRC.
Effects of a Skewed Inlet Boundary Layer on the Aerodynamic Performance of a Stator-Hub Equivalent High-Turning Compressor Cascade
Authors: Bode Christoph , Hoffmann Jörg , Stark Udo
Published: September 2016

The paper reports on numerical investigations into the effects of inlet boundary layer skew on the aerodynamic performance of a low aspect ratio, high turning compressor cascade. The cascade geometry corresponds to the hub section geometry of a low aspect ratio stator of a highly loaded single-stage axial-flow low-speed compressor (fan). The skewed cascade flow simulates the reenergized stator hub flow and brings about a much better performance with inlet skew than without. However, the performance improvements caused by a skewed inlet boundary layer decrease with increasing inlet angle.
Experimental Investigation on Flow Resistance and Heat Transfer Coefficient of Internal Lamilloy
Authors: Zhang Wei , Zhu Huiren , Li Guangchao , Shang Chunyu , Liu Cunliang
Published: September 2016

Flow resistance and heat transfer coefficients of the lamilloy with two kinds of film hole pitch were experimentally studied at the impinging Reynolds numbers ranging from 1×104 to 6×104. The detailed distributions of pressure coefficients on the target plate, impingement plate and pin-fins, local loss coefficients of jet, channel flow, effusion and the flow resistance coefficients of lamilloy were obtained by using a lot of pressure taps. The dense grids of the surfaces were generated and the pressure values of all the grid points were obtained by Kriging interpolation method based on the experimental data. Distributions of heat transfer coefficients on the target and the impingement surfaces ( The surface of the impingement plate in the impingement hole outlet surface) were tested by the transient liquid crystal technique. The coolant temperatures of both impingement hole inlet and the film hole outlet were measured by K type thermocouples. The results show that the pressure coefficients on the jet stagnation region increase firstly and then decrease along the radius direction from stagnation point. The pressure distributions on the two rows of pin-fins near the two film hole rows are significantly affected by the Reynolds numbers. The pressure coefficient values are nearly the same in the pin fin height direction which means the flow pattern near the pin fins of this two rows likes the crossflow past a circular cylinder at Re=3×104 and has the characteristics of reverse flow and flow around circular cylinder at Re=4×104. The loss coefficients of effusion are the biggest, those of channel flow are the second and those of impingement jet are the smallest. The loss coefficients of effusion of film hole increase at least 4 times and those of the impingement jet and the channel flow change slightly when the spacing of film hole decreases one half. The averaged heat transfer coefficient of target surface is higher than that of the impingement surface. This difference becomes obvious with the increase of Reynolds number. The differences of Nusselt number on the impingement surface and the target surface are 16% and 10% respectively under the two models at the Reynolds number of 6×104, indicating that the hole pitch has a weak influence on the averaged heat transfer coefficients. The second peak of heat transfer coefficients was found.
Flexible Combined Cycle Gas Turbine Power Plant Utilising Organic Rankine Cycle Technology
Authors: Welch Michael , Rossetti Nicola
Published: September 2016

Historically gas turbine power plants have become more efficient and reduced the installed cost/MW by developing larger gas turbines and installing them in combined cycle configuration with a steam turbine. These large gas turbines have been designed to maintain high exhaust gas temperatures to maximise the power generation from the steam turbine and achieve the highest overall electrical efficiencies possible.

However, in today’s electricity market, with more emphasis on decentralised power generation, especially in emerging nations, and increasing penetration of intermittent renewable power generation, this solution may not be flexible enough to meet operator demands.

An alternative solution to using one or two large gas turbines in a large central combined cycle power plant is to design and install multiple smaller decentralised power plant, based on multiple gas turbines with individual outputs below 100MW, to provide the operational flexibility required and enable this smaller power plant to maintain a high efficiency and low emissions profile over a wide load range. This option helps maintain security of power supplies, as well as providing enhanced operational flexibility through the ability to turn turbines on and off as necessary to match the load demand.

The smaller gas turbines though tend not to have been optimised for combined cycle operation, and their exhaust gas temperatures may not be sufficiently high, especially under part load conditions, to generate steam at the conditions needed to achieve a high overall electrical efficiency.

ORC technology, thanks to the use of specific organic working fluids, permits efficient exploitation of low temperatures exhaust gas streams, as could be the case for smaller gas turbines, especially when working on poor quality fuels.

This paper looks at how a decentralised power plant could be designed using Organic Rankine Cycle (ORC) in place of the conventional steam Rankine Cycle to maximise power generation efficiency and flexibility, while still offering a highly competitive installed cost. Combined cycle power generation utilising ORC technology offers a solution that also has environmental benefits in a water-constrained World.

The paper also investigates the differences in plant performance for ORC designs utilising direct heating of the ORC working fluid compared to those using an intermediate thermal oil heating loop, and looks at the challenges involved in connecting multiple gas turbines to a single ORC turbo-generator to keep installed costs to a minimum.
Influence of Inflow Turbulence and Distortion on a Two-Stage Low Pressure Axial Turbine at Low Reynolds Numbers
Authors: Schulze Christian H. , Habermann Jan , Staudacher Stephan , Rose Martin G. , Freygang Udo
Published: September 2016

A two-stage low pressure turbine, developed by MTU Aero Engines AG (MTU), has been tested in the altitude test facility of the Institute for Aircraft Propulsion Systems (ILA) at Stuttgart University. The focus was on the change in the turbines behaviour to a rise in inflow turbulence levels and inflow distortion at flight conditions. Hence, the turbine flow with a clean inlet was compared to two cases with a built in turbulence grid prior to the first vane at a Reynolds number of 75,000. Data was collected in the inflow and inside the turbine using radial and area probe traverses. The observed rise in inflow turbulence level and the inflow distortion impacted the first turbine nozzle guide vane. Static pressure tappings and thin film gauges show changes in separation as well as transition location on the vane’s suction side. Five hole probe and 3D hot film probe measurements show distinct changes in secondary flow patterns as well as nozzle guide vane wakes. The changes lead to a higher blade row efficiency and a more homogeneous distribution of turbulence intensity at stator exit.
Influence of Boundary Layer Air Injection on Flashback of Premixed Hydrogen-Air Flames
Authors: Hoferichter Vera , Mohammadzadeh Keleshtery Payam , Hirsch Christoph , Sattelmayer Thomas , Matsumura Yoshikazu
Published: September 2016

Alternative fuels like hydrogen are presently discussed as one possibility to reduce carbon dioxide emissions from gas turbines. Premixed lean combustion is a current standard to minimize nitrogen oxide emissions. However, the early mixing of fuel and oxidizer upstream of the combustion chamber opens up the possibility of upstream flame propagation, referred to as flame flashback. Flame flashback in gas turbines has to be prevented as it leads to immediate engine shut down or even structural damage. Due to high burning velocities and low quenching distances, flashback is especially critical in premixed hydrogen flames. In particular, the low velocity region near the burner wall promotes flashback. Diluting the mixture near the wall by fluid injection is one approach to counteract this phenomenon and to enhance the safe operating range of a gas turbine burner.

This article presents an experimental study on the effect of air injection on flame flashback investigated at a channel burner configuration. Different injection mass flow rates, positions and angles are compared to a reference case without injection regarding their flashback limits. The effectiveness of the injection increases with the injected mass flow rate. The resulting flashback limits can be correlated with the equivalence ratio at the wall by concepts taken from film cooling. However, the fluid injector is a source of boundary layer disturbances leading to an initial penalty regarding flashback resistance. This penalty increases the closer the injector is located to the burner exit. Furthermore, the penalty increases for lower injection angles as the area of the injector and the corresponding boundary layer disturbances increase.