bluuebunny/crossref_metadata_2025 huggingface dataset:
The mediating effect of emotional intelligence between emotional labour, job stress, burnout and nurses' turnover intention
Authors: Hong Eunyoung , Lee Young Sook
Published: September 2016

This study was designed to construct and test the structural equation modelling on nurses' turnover intention including emotional labour, job stress, emotional intelligence and burnout in order to identify the mediating effect of emotional intelligence between those variables. Emotional labour, job stress and burnout increase turnover intention of nurses. However, emotional intelligence is negatively correlated with emotional labour and reduces job stress, burnout and turnover intention. Structural equation modelling was used to analyse the goodness of fit of the hypothetical model of nurses' turnover intention. Research data were collected via questionnaires from 4 to 22 August 2014 and analysed using SPSS version 18.0 and AMOS version 20.0. The model fit indices for the hypothetical model were suitable for recommended. Emotional intelligence has decreasing effect on turnover intention through burnout, although its direct effect on turnover intention is not significant. Emotional intelligence has mediation effect between emotional labour and burnout. This study's results suggest that increasing emotional intelligence might critically decrease nurses' turnover intention by reducing the effect of emotional labour on burnout.
Responding to Non‐Linear Internationalisation of Public Policy: The World Trade Organization and Reform of the CAP 1992–2013
Authors: Daugbjerg Carsten
Published: September 2016

The transfer of regulatory authority to international organisations can initiate domestic policy reform. The internationalisation process can be a one‐off transfer of authority to international institutions or an ongoing process. In the latter situation, the level of internationalisation may be gradually increased by expanding the regulatory scope of the regime or by deepening it. However, internationalisation processes may also involve stalemate or even reversal. How do domestic policy makers respond to such non‐linear internationalisation? To answer this question, this paper analyzes the relationship between developments in the GATT and WTO farm trade negotiations and the reform trajectory of the EU's Common Agricultural Policy (CAP) from the early 1990s to 2013. Until 2008, the EU gradually changed the support instruments of the CAP to limit their trade distorting impact. After the Doha Round stalled in 2008, international trade policy concerns were downgraded and domestic concerns took priority in the 2013 reform.
Treatment of sporadic port‐wine stains: a retrospective review of 17 cases consecutively treated by pulsed sequential dual wavelength 595 and 1064 nm laser
Authors: Perruchoud D.L. , Cazzaniga S. , Heidemeyer K. , Weber B. , Dietrich N. , Borradori L. , Adatto M.A.
Published: September 2016

Background

Port‐wine stains (PWS) are relatively common and often cause cosmetic and psychological concerns. The pulsed dye laser is currently the treatment of choice for PWS.

Objective

To assess the effectiveness of the pulsed sequential dual wavelength 595 and 1064 nm laser as first‐line treatment for PWS and to identify prognostic factors for treatment outcome in a retrospective series of 17 consecutive previously untreated patients.

Methods

The response to treatment was evaluated 2 months after treatment utilizing comparative photographs and a standard physician global assessment (PGA) grading system. Furthermore, measurement of the normalized erythema index (NEI) reduction (ΔNEI%) was carried out using an image analysis system. The subjective improvement was assessed using a patient's satisfaction questionnaire. Multiple linear regression models were finally used to identify factors associated with ΔNEI% and patients’ satisfaction.

Results

Seventeen patients, with PWS, including 12 children were included. The average PGA assessment was 2.5 ± 1.3 corresponding to an amelioration of 50% with a high intraclass correlation coefficient among the experts. The before–after NEI showed a statistically significant mean reduction of 3.5 ± 2.6 units, corresponding to a relative reduction of 31%. Questionnaires showed that the satisfaction was very good with an average score of 6.1 points on a scale ranging from −10 to 10 points. Multiple regression analysis revealed that location in the frontotemporal area was associated with a significant reduction in ΔNEI% (38.4%; 95% CI 4.3, 72.6). Presence of PWS on the neck was associated with a lower patient satisfaction (−3.7 points; 95% CI −6.5, −0.9). There were no significant side‐effects, except for transient discomfort and purpura.

Conclusions

Based on the results obtained in the largest reported series so far, the pulsed sequential dual wavelength 595 and 1064 nm laser represents an effective and safe first‐line therapeutic option for the treatment of PWS.
Carbon Emission Performance of China's Power Industry: Regional Disparity and Spatial Analysis
Authors: Wang Xiping , Du Lei
Published: September 2016

This study employs an undesirable‐output–oriented data envelopment analysis model to measure the carbon emission performance of the power industry throughout China's 30 administrative regions during the period of 2003–2012. Also, it further studies the regional disparity and spatial correlation of the carbon emission performance of China's power industry. The main findings are as follows: (1) The carbon emission performance of China's power industry is at a relatively low level, but shows a rising trend. (2) The regional carbon emission performance of China's power industry is extremely unbalanced: The eastern area ranks first, with the highest performance of 0.851, followed by the central area, whereas the western area falls behind, with the lowest performance of 0.760. Provinces in the eastern area generally perform better than those in other areas. (3) According to spatial analysis, the global Moran's I values of carbon emission performance are significantly positive during the sample period, which indicates that the carbon emission performance is a positive spatial correlation and has an obvious clustering effect. The estimate of the local spatial autocorrelation index confirms the imbalance of spatial distribution of the power sector's carbon emission performance. Based on the above findings, several policy suggestions are presented in this article.
IL‐1β maintains the redox balance by regulating glutaredoxin 1 expression during oral carcinogenesis
Authors: Chen Xijuan , Lv Qianshu , Hong Yun , Chen Xiaobing , Cheng Bin , Wu Tong
Published: September 2016

Background

Interleukin‐1 beta (IL‐1β) is a pleiotropic cancer–inflammation‐linked cytokine which has been reported upregulated in many cancers. In our previous study, IL‐1β was found to be one of the key node genes during oral malignant transformation, and glutaredoxin 1 (Grx1) was identified as one of the downstream genes of IL‐1β in tumor microenvironment. Grx1 is ubiquitous oxidoreductase which is necessary for scavenging reactive oxygen species (ROS) and the intracellular redox balance maintenance.

Methods

Tissues from different stages of mucosal malignant transformation were obtained from 4NQO‐induced rat oral carcinogenesis model and human mucosa for Grx1 expression detection by immunohistochemical staining. The intracellular ROS levels and Grx1 mRNA level of oral squamous carcinoma cell CAL27 were detected after IL‐1β treatment with or without pretreatment of IL‐1Ra or NAC, respectively. The ROS levels were detected in Leti‐si‐IL‐1β and Leti‐si‐NC CAL27 cells after IL‐1β stimulation. The invasion and migration abilities of CAL27 cells were tested by transwell assay after IL‐1β stimulation with or without pretreatment of IL‐1Ra.

Results

Grx1 expression was associated with the malignant transformation process in vivo. Exogenous IL‐1β upregulated the intracellular ROS level and the expression of Grx1 in CAL27 cells, which could be counteracted by IL‐1Ra. The intracellular ROS accumulation induced by exogenous IL‐1β was responsible for the Grx1 upregulation. Endogenous IL‐1β acted as a switch in regulating the ROS level by modulating Grx1 expression, which was involved in the invasion and migration of OSCC cells.

Conclusions

IL‐1β finely orchestrated the redox balance during carcinogenesis by modulating Grx1 expression.
Characterization and bake stability of dry fruit fillings in dehydrated chiku (Manilkara zapota L. P. Royen) incorporated biscuits
Authors: Aditi Mahapatra , Shashirekha M. N. , Sudha M. L.
Published: September 2016

Expanding the range of bakery products in terms of producing supplemented or dietetic products has been an increasingly important trend in contemporary baking. Value added products, especially products rich in fiber and phytochemicals are getting popular. Among the dry fruits used for filling, Figs were rich in ash and protein and Dates were rich in dietary fiber. Gallic acid was the dominant free phenolic acid in Fig whereas chlorogenic acid and procatechuic acid were dominant in Dates in the bound form. Farinograph water absorption, dough development time, maximum pressure (P), and extensibility (L) decreased on increase in the replacement of wheat flour with chiku powder from 0 to 30%. The dry fruit fillings in the pH range of 3.3–3.5 with 75–80°Bx showed better bake stability with respect to spreadability and breaking strength. Biscuits topped with higher °Bx fillings had higher breaking strength values even during storage. Among the gelling agents used, addition of sodium alginate stabilized and further improved the bake stability of the fillings. The chiku incorporated biscuits sandwiched with fruit filling were rich in dietary fiber. Also significant amounts of gallic acid and chlorogenic acid in free and bound form were present in the biscuit.

Practical applications

Bakery products can act as a vehicle for supplementation of vitamins, minerals, protein, dietary fiber, and so on, to prevent nutritive deficiencies. Among the bakery products, biscuits are shelf stable and have better consumer acceptability by all age groups. To incorporate fruits which are rich in many bioactive principles, and to add on to variety, fruit sandwiched biscuits with fruit powder in the casing too. Fillings mainly from dry fruits were prepared at varying degree brix and with different gelling agents. Biscuit sheets containing chiku powder in the formulation was topped with the fillings and looked for the bake stability with respect to texture and spreadability. Addition of fruit powder in the shells and fruit filling in between helped to increase the nutritional characteristics of the product.
The Need for a Lengthier Cryolesion Can Predict a Worse Outcome in 3D Cryoablation of AV Nodal Slow Pathway in Children
Authors: DRAGO FABRIZIO , RUSSO MARIO SALVATORE , BATTIPAGLIA IRMA , GRIFONI GINO , SILVETTI MASSIMO STEFANO , REMOLI ROMOLO , PAZZANO VINCENZO , SAPUTO FABIO ANSELMO , CIANI MICHELE
Published: September 2016

Background

Transcatheter cryoablation is a well‐established technique for the treatment of atrioventricular nodal reentry tachycardia (AVNRT) in children. Nevertheless, atrioventricular nodal slow‐pathway conduction may recur after an acutely successful procedure. The aim of this study was to evaluate the long‐term outcome of acutely successful AVNRT cryoablations in pediatric patients in case of focal cryolesion and in case of need for High‐Density Linear Lesion (HDLL) cryoablation due to focal failure.

Methods

Sixty‐nine consecutive pediatric patients (30 males, mean age 12.4 ± 3.2 years; range: 5.4–18.0 years) underwent 3D‐guided cryoablation for AVNRT at our institution from July 2013 to November 2014. When a focal cryoablation was acutely unsuccessful, a 3D‐guided HDLL was created delivering multiple overlapping cryolesions/cryoenergy applications from the ventricular side of the tricuspid annulus to the atrial side, including the site of focal cryoablation if transiently successful.

Results

No permanent cryoablation‐related complications occurred. Acute success rate was 98.5% (68 out of 69): in 55.9% (38 out of 68) with focal‐lesion and in 44.1% (30 out of 68) with HDLL. Mean follow‐up was 25.3 months and AVNRT recurrence rate was 13.2% (nine out of 68): 5.2% (two out of 38) with focal lesion and 23.3% (seven out of 30) with HDLL (P = 0.036).

Conclusions

In cryoablation of AVNRT in children, the need for a more aggressive protocol (HDLL), due to the failure of focal ablation, is strictly related to higher recurrence rates. Indeed, AVNRT recurrences after cryoablation in children seem to be due to a larger and deeper substrate rather than due to the type of energy used.
Genetic Testing in Dermatology: A Survey Analyzing Obstacles to Appropriate Care
Authors: Shagalov Devorah R. , Ferzli Georgina M. , Wildman Temima , Glick Sharon A.
Published: September 2016

Background/Objectives

The past several decades have witnessed unprecedented advances in genomic technology, bringing genetic testing to the forefront of medical practice and moving us towards the practice of personalized medicine. Genetic testing has become an important aspect in preempting and successfully treating diseases in dermatology, yet difficulty remains in regards to obtaining genetic testing for patients. We conducted a survey for pediatric dermatologists in order to try to gauge and understand where difficulties lie in obtaining genetic testing and to analyze how best these issues can be resolved.

Methods

An 18‐question survey was emailed to 480 dermatologists who have attended at least one of the last three annual Society for Pediatric Dermatology (SPD) meetings.

Results

Virtually all providers encountered at least one situation in which they required genetic testing for a patient (97.3% [n = 108]) and 37.4% indicated needing genetic testing more than six times per year. Of the respondents who had attempted to obtain genetic testing, half were unsuccessful in obtaining coverage more than 75% of the time (45% [n = 32]) and only 7.0% (n = 5) achieved success 75% to 100% of the time. The most common reasons for obtaining genetic testing included the need to provide an accurate diagnosis, followed by the need to provide prognostic information and appropriate medical management.

Conclusion

The role of genetic testing in the practice of dermatology is expanding, yet obtaining coverage for genetic testing remains a challenge. We propose several solutions as to how this can be remedied.
Light quality and quantity regulate aerobic methane emissions from plants
Authors: Martel Ashley B. , Qaderi Mirwais M.
Published: September 2016

Studies have been mounting in support of the finding that plants release aerobic methane (CH4), and that these emissions are increased by both short‐term and long‐term environmental stress. It remains unknown whether or not they are affected by variation in light quantity and quality, whether emissions change over time, and whether they are influenced by physiological parameters. Light is the primary energy source of plants, and therefore an important regulator of plant growth and development. Both shade‐intolerant sunflower and shade‐tolerant chrysanthemum were investigated for the release of aerobic CH4 emissions, using either low or high light intensity, and varying light quality, including control, low or normal red:far‐red ratio (R:FR), and low or high levels of blue, to discern the relationship between light and CH4 emissions. It was found that low levels of light act as an environmental stress, facilitating CH4 release from both species. R:FR and blue lights increased emissions under low light, but the results varied with species, providing evidence that both light quantity and quality regulate CH4 emissions. Emission rates of 6.79–41.13 ng g−1 DW h−1 and 18.53–180.25 ng g−1 DW h−1 were observed for sunflower and chrysanthemum, respectively. Moreover, emissions decreased with age as plants acclimated to environmental conditions. Since effects were similar in both species, there may be a common trend among a number of shade‐tolerant and shade‐intolerant species. Light quantity and quality are influenced by factors including cloud covering, so it is important to know how plants will be affected in the context of aerobic CH4 emissions.
ULASAN KAEDAH KITAR SEMULA SISA BATERI
Authors: Moktamin Farhah Abdillahil , Choo Ta Goh , Mokhtar Mazlin , Ariffin Mohd Rozaimi
Published: September 2016

The generation of waste batteries is increasing due to the wide application and short life span of batteries. The heavy metals used inside a battery are highly toxic and can cause harm to humans and to the environment. However, if waste batteries are recovered properly through a recycling process, precious metals inside the batteries can be extracted. In general, there are three methods for recycling waste batteries, namely pyrometallurgy, hydrometallurgy and bio-hydrometallurgy. This article reviews and discusses the efficiency and effectiveness of these methods in recycling waste batteries. Based on the review, each recycling method has its specific characteristics. The hydrometallurgy method tends to be used for recycling Li-ion batteries while the pyrometallurgy method tends to eliminate plumbum in automotive waste batteries. In general, the hydrometallurgical method is commonly used for recycling batteries due to its shorter process and lower cost.
INVESTIGATION OF SURFACE ROUGHNESS IMPACT ON MEAN WIND FLOW USING RNG k-ε MODEL
Authors: Shaikh Salim Sheikh Ahmad Zaki , Jaafar Ahmad Zaki , Mohammad Ahmad Faiz , Mohamed Mat Ali Sukri , Abd Razak Azli
Published: September 2016

Wind flow in the urban boundary layer is influenced by both large- and small-scale surface roughness. In this study, Reynolds-averaged Navier-Stokes simulations using the renormalisation group (RNG) k-ε model were performed to study the wind flow in square arrays with small-scale roughness elements at the front and back of cubical obstacles at packing densities of 25.0% and 30.9%. The presence of small-scale roughness reduces streamwise velocity but increases turbulent kinetic energy. Moreover, small vortices are formed within the canopy because of small-scale roughness. The generated streamwise velocity profiles are similar at packing densities of 25.0% and 30.9%, but the drag coefficient is higher in the latter case. In brief, the impact of small-scale roughness on urban wind flow is considerable. The results of this study can contribute to future research on wind flow, particularly in the urban environment.
HOW SIGNIFICANT IS DURABILITY IN VERNACULAR HOUSE CONSTRUCTION?
Authors: Ghafouri Mehdi , Khan Tareef Hayat , Ahmad Abdullah Sani
Published: September 2016

For centuries, dynamic vernacular society has experienced repairing, or demolishing old houses, and constructing new houses. The time interval between those actions probably became more sparsely spread as modern and more durable technologies and materials offered wider range of options in the vernacular construction through globalization. The first objective of this paper was to compare the durability of distinctively old and new construction materials and technologies used in the vernacular houses in a context of northern Iran. The second objective was to search implicit values behind making decisions regarding durability. The ‘old’ construction technologies were ‘Kali’, Mud Houses, and Lar deh ee”, and, while Load-bearing wall, Concrete, and Steel structure were the ‘new’ categories. A questionnaire-based survey was conducted among 167 residents of different vernacular houses and 18 of them were selected for interview. Besides, a number of 20 experts also participated in a mailing survey for validating the data. Perception of users on durability of structure was assessed and compared through 5 elements namely foundation, floor, wall, roof, and attachment through the structured-questionnaire, while the implicit values were revealed from data collected through the open-ended interview. Results showed that residents tend to rate the old houses higher, rather controversially. Commercialization might be gradually inclining users’ choices towards new houses, but responses also showed that a house is likely to be redundant after only a couple of generations, even though it still has a long durable lifetime to spare, thus making the durability issue less significant.
A VARIABLE NEIGHBORHOOD SEARCH FOR THE HETEROGENEOUS FIXED FLEET VEHICLE ROUTING PROBLEM
Authors: Imran Arif , Luis Martino , Okdinawati Liane
Published: September 2016

The heterogeneous fixed fleet vehicle routing problem (HFFVRP) is investigated using the variable neighborhood search (VNS). The initial solution is generated using the Sweep algorithm and the 2-opt procedure and then the customers are allocated to the smallest vehicle first by considering vehicle occupancy level. The proposed VNS algorithm uses several neighborhoods and a number of local search methods which are adapted for this problem. The local searches are implemented within a multi-level framework. The performance of the proposed algorithm is then tested using data set taken from literature and the experiments show competitive results with less computing time. Future research directions are also highlighted.
THE STUDY OF OPTICAL GAIN FOR TERAHERTZ QUANTUM CASCADE LASER USING DENSITY MATRIX METHOD
Authors: Mohd Akil Mohd Asmu'i , Akabli Khalid , Shaari Amiruddin , Kasmin Mohd Khalid , Othaman Zulkafli
Published: September 2016

Terahertz (THz) quantum cascade lasers (QCL) are currently increasing in popularity. It is expected to become the main source of emerging terahertz radiation technology and applications. However to produce the device within the application specification is costly and time consuming. This is because the manufacturing process of the superlattice growth and the device processing and testing are long and expensive processes. Thus a prediction tool is needed to overcome the problems in designing and producing THz QCL within the needed optical expectation. The density matrix method is used to calculate the performance of this device electronically and optically. The result obtained was compared to the experimental result conducted by previous researchers. The calculation result showed that the gain is 20  when the population inversion occurs at threshold current density of 400 A cm-2. Meanwhile a negative gain or loss occurs below 350 A cm-2. As a conclusion, it is demonstrated that this method has a capability to explain the transport phenomena as well as to predict the performance of the THz QCL device design.
DYNAMIC SIMULATION MODEL OF ELECTRICITY ENERGY DEMAND AND POWER PLANT CAPACITY PLANNING IN MADURA
Authors: Suryani Erma , Agus Hendrawan Rully , Dewi Lily Puspa
Published: September 2016

As a country that has many islands, Indonesia faces a challenge of inequality electrification ratio. The big islands with dense population such as Java and Sumatra could build large electricity generation plants and distribute electricity with economies scale. On the other hand, it is not economical to build large power plants on small and isolated islands; because of the investment cost per number of population is still very high. Therefore, a strategy to build an independent power plant in small island such as Madura is still a challenge for the government. In addition, to build a power plant in Madura, requires a comprehensive analysis of electricity energy needs in the future and capacity planning to fulfill the demand. Madura has the potential to develop its own power plant. However, Madura still relies on supplies from the island of Java. Therefore, in this research, we use system dynamics as a framework to develop a simulation model to project the future demand and power plant capacity planning based on consideration that system dynamics can conduct the demand projection and capacity planning as well as developing scenarios to fulfill demand in 25 years.
OPTIMIZATION OF A THERMOACOUSTIC REFRIGERATOR WITH AN EVOLUTIONARY ALGORITHM APPROACH
Authors: Zolpakar Nor Atiqah , Mohd-Ghazali Normah
Published: September 2016

Current non-environmentally friendly refrigerants released into our environment have caused serious concern over reports of the depleting of the ozone layer and global warming. Alternative technologies and efficient energy-related systems are being investigated to perhaps reduce if not stop the environmental degradation. This paper reports the outcomes of an optimization procedure performed on an environmentally friendly standing wave thermoacoustic refrigerator. A typical system to date has a low coefficient of performance (COP) and thus is not attractive to the general public. Optimization is completed using genetic algorithm over four design variables; the stack length and center position within a thermoacoustic resonator, the blockage ratio, and drive ratio. Optimization results show a maximum COP obtainable at 1.64. The outcomes indicate a potential for better thermoacoustic refrigerators in future.
Spherical Hands: Toward Underactuated, In-Hand Manipulation Invariant to Object Size and Grasp Location
Authors: Ma Raymond R. , Rojas Nicolas , Dollar Aaron M.
Published: September 2016

Minimalist, underactuated hand designs can be modified to produce useful, dexterous, in-hand capabilities without sacrificing their passive adaptability in power grasping. Incorporating insight from studies in parallel mechanisms, we implement and investigate the “spherical hand” morphologies: novel, hand topologies with two fingers configured such that the instantaneous screw axes, describing the displacement of the grasped object, always intersect at the same point relative to the palm. This produces the same instantaneous motion about a common point for any object geometry in a stable grasp. Various rotary fingertip designs are also implemented to help maintain stable contact conditions and minimize slip, in order to prove the feasibility of this design in physical hand implementations. The achievable precision manipulation workspaces of the proposed morphologies are evaluated and compared to prior human manipulation data as well as manipulation results with traditional three-finger hand topologies. Experiments suggest that the spherical hands' design modifications can make the system's passive reconfiguration more easily predictable, providing insight into the expected object workspace while minimizing the dependence on accurate object and contact modeling. We believe that this design can significantly reduce the complexity of planning and executing dexterous manipulation movements in unstructured environments with underactuated hands.
Influence of Continuous Direct Current on the Microtube Hydroforming Process
Authors: Wagner Scott W. , Ng Kenny , Emblom William J. , Camelio Jaime A.
Published: September 2016

Research of the microtube hydroforming (MTHF) process is being investigated for potential medical and fuel cell applications. This is largely due to the fact that at the macroscale the tube hydroforming (THF) process, like most metal forming processes, has realized many advantages, especially when comparing products made using traditional machining processes. Unfortunately, relatively large forces compared to part size and high pressures are required to form the parts so the potential exists to create failed or defective parts. One method to reduce the forces and pressures during MTHF is to incorporate electrically assisted manufacturing (EAM) and electrically assisted forming (EAF) into the MTHF. The intent of both EAM and EAF is to use electrical current to lower the required deformation energy and increase the metal's formability. To reduce the required deformation energy, the applied electricity produces localized heating in the material in order to lower the material's yield stress. In many cases, the previous work has shown that EAF and EAM have resulted in metals being formed further than conventional forming methods alone without sacrificing the strength or ductility. Tests were performed using “as received” and annealed stainless steel 304 tubing. Results shown in this paper indicate that the ultimate tensile strength and bust pressures decrease with increased current while using EAM during MTHF. It was also shown that at high currents the microtubes experienced higher temperatures but were still well below the recrystallization temperature.
Gas Turbine Blade Cooling Passage With V and Broken V Shaped Ribs
Authors: Kumar Sourabh , Amano Ryoichi S.
Published: September 2016

Gas turbine plays a significant role throughout the industrial world. Aircraft propulsion, land-based power generation, and marine propulsion are most notable sectors where gas turbines are extensively used. The power output in these applications can be increased by raising the temperature of the gas entering the turbines. Turbine blades and vanes constrain the temperature of hot gases. For internal cooling design, techniques for heat extraction from the surfaces exposed to hot stream are based on increasing heat transfer areas and the promotion of turbulence of the cooling flow. Heat transfer is enhanced for example due to ribs, bends, rotation and buoyancy effects; all characterizes flow within the channels. Computational Fluid Dynamics (CFD) simulations are carried out using turbulence models like Large Eddy Simulation (LES) and Reynolds stress model (RSM). These CFD simulations were based on advanced computing technology to improve the accuracy of three-dimensional metal temperature prediction that can be applied routinely in the design stage of turbine cooled vanes and blades. The present work is done to study the effect of secondary flow due to the presence of ribs on heat transfer. In this paper, it is obtained by casting repeated continuous V and broken V-shaped ribs on one side of the two passes square channel into the core of blade. Two different combinations of 60° V and Broken 60° V-ribs in the channel are considered. This work is an attempt to collect information about Nusselt number inside the ribbed duct. Large Eddy Simulation (LES) is carried out on the Inlet V and Inverted V outlet continuous and Broken Inlet V and Inverted V-rib arrangements to analyze the flow pattern inside the channel. Hybrid LES/Reynolds Averaged Navier-Strokes (RANS) modeling is used to modify Reynolds stresses using Algebraic Stress Model (ASM), and a CFD strategy is proposed to predict heat transfer across the cooling channel.
An Acoustic Excitation System for the Generation of Turbomachinery Specific Sound Fields: Part I — Design and Methodology
Authors: Mumcu Akif , Keller Christian , Hurfar C. Mandanna , Seume Joerg R.
Published: September 2016

A strong focus in the development of modern aircraft engines is the reduction of the engine tonal core noise. For the development of efficient noise reduction techniques, a detailed understanding of the sound transmission throughout all turbomachinery components of the engine is mandatory. In this paper an excitation system is developed to generate turbomachinery-specific sound fields by controlling their circumferential and radial mode order. The excitation system consists of two rows of eight loudspeakers distributed circumferentially around the outer duct wall. This paper gives a detailed description of the analytically- and numerically-supported design methodology of an optimized excitation system, as well as an optimized microphone array mounted flush with the outer duct wall. A sensitivity analysis of the loudspeaker array and of the microphone array with respect to distance and frequency is then carried out numerically. To analyze the microphone signals and to deconstruct the propagating sound field into its modal components, a Radial Mode Analysis (RMA) is carried out. To ensure high-quality RMA results, the axial distribution of the microphones is optimized with respect to the condition number of the array’s transfer matrix. The procedure explained in this paper shall help guide the development of acoustic excitation and microphone array systems for experiments to better understand sound propagation in turbomachinery and flow ducts.
Flat-Plate Boundary Layers in Accelerated Flow
Authors: Bader Pascal , Pschernig Manuel , Sanz Wolfgang , Woisetschläger Jakob , Heitmeir Franz , Meile Walter , Brenn Günter
Published: September 2016

Flow in turbomachines is generally highly turbulent. The boundary layers, however, often exhibit laminar-to-turbulent transition. But also relaminarization of the turbulent flow may occur. The state of the boundary layer is important, since it strongly influences transport phenomena like skin friction and heat transfer.

It is therefore vitally important for the designer to understand the process of boundary layer transition and to determine the position of transition onset and the length of the transitional region. In order to get into the details of transition and relaminarization it is helpful to study simplified test cases first. Therefore, in this paper a relaminarization test case for a simple geometry is investigated: The boundary layer flow along a flat plate is exposed to acceleration with three different acceleration parameters, which is known as a crucial parameter for relaminarization.

Measurements were performed for the inlet free-stream velocities of 5 m/s and 9 m/s. Several experimental techniques for detecting transition were tested at the institute before their application. In this work, Laser-Doppler anemometry (LDA) measurements were performed, since this optical technique is non-intrusive and does not disturb the flow. Therefore it can also be used in narrow flow passages where probe blockage can be crucial.

As an outcome of this study, an insight into the process of relaminarization is presented.

Although the key onset values for relaminarization stated in literature are fulfilled with the test setup, full relaminarization over the whole boundary layer has not been achieved. It seems, that using only the skin friction as indicator for relaminarization is not sufficient.
Short Helical Combustor: Dynamic Flow Analysis in a Combustion System With Angular Air Supply
Authors: Ariatabar Behdad , Koch Rainer , Bauer Hans-Jörg
Published: September 2016

A novel gas turbine combustor which features a helical arrangement of the burners around the turbine shaft has been subject of a detailed flow analysis. A fundamental investigation of the combustor concept has been conducted in the authors previous work [1]. The main design parameters for such a combustor were identified based on kinematic assessments of the flow fields predicted by CFD.

In particular, it has been shown in the previous work that the swirl rotational direction of adjacent burners determines the overall flow pattern in such a staggered design of the combustor dome. However, for the optimal configuration the exit mean flow angle was lower than the half of its initial value at the combustor inlet. The reason for this unwanted decay of the initial high angular momentum flux was not clear.

In the present work a comprehensive global flow analysis of such a short helical combustor is performed. The underlying physics of large changes of the flow pattern and exit flow angle are elucidated by the analysis of the different terms (momentum, pressure and friction) in the integral balance equation of angular momentum. The term “dynamic flow analysis” is used in contrast to the “kinematic flow analysis” in our previous work and does not refer to transient flow phenomena.

It is shown that the flow in the vicinity of the burners is governed by inertial forces associated to an asymmetric pressure distribution on the sidewall and the combustor dome. Downstream the sidewalls, the swirl rotational direction of circumferentially adjacent burners determines the structure of vortex-breakdown and the flow pattern in the primary combustion zone. It is shown that the turbulent mixing phenomena have minor effects on the flow structure at the combustor exit.

To compare mean flow quantities of different combustor designs, a consistent averaging method is introduced which is based on the work of the Pinako and Wazelt [2].

This analysis can also be applied to conventional combustors to assess different swirl configurations regarding the resulting flow pattern, mixing performance and total pressure loss.
Working Process Control in a Ship Gas Turbine Engine of Complex Cycle
Authors: Matviienko Valerii , Ocheretianyi Volodymyr , Andriets Oleksandr , Riznyk Sergiy
Published: September 2016

Gas turbine engines (GTE) of complex cycles are more efficient in comparison to GTE of simple cycle, and they can be recommended for application in a ship propulsion complex. GTE’s representative of complex cycle is GTE with overexpansion turbine and heat regeneration, which has high efficiency, and which can provide heat energy to the consumers of specialized ships in co-generative mode of operation.

GTE with R and OT is adapted for used in different conditions of ships’ operation. It has high power efficiency at partial loads due to the working process control in the engine. There are two applicable methods of getting required engine’s characteristics of GTE with heat regeneration at partial loads.

If more constant production of heat energy is required at partial loads of the main engine, the method of air by-pass to the combustion chamber by recuperator is applied. Hereby, utilized heat is being redistributed towards the gas cooler boiler-utilizer increasing its power.

For the increase of efficiency of GTE with R and OT at partial loads it is used the method of GTE’s characteristics change by application of variable area nozzles (VAN) of power turbine. VAN in GTE with R allows keeping initial temperature of gas in the engine close to nominal value at partial loads. If the efficiency of GTE with R and OT at nominal load is 20 % relatively higher, in this case when power is equal to 50%, the efficiency of GTE with R and OT is 30% higher in relation to Brayton cycle. In GTE with R and OT it is possible to apply two methods of working process control simultaneously in various regimes of ship operation.
Performance Prediction and Early Design Code for Axial Turbines and its Application in Research and Predesign
Authors: Krumme Alexander
Published: September 2016

This paper presents DLR’s in-house Performance prediction and Early Design Code for axial Turbines PrEDiCT. It is capable of designing multi-stage, multi-spool air-breathing turbines with consideration of coolant flows and different loading levels, relevant for energy, aircraft and general turbomachinery.

After pointing out the integration of PrEDiCT into the DLR predesign process and the role of each method involved, its iterative main calculation routine will be presented as well as its thermodynamic and geometrical methods to output a complete turbine annulus with preliminary blades, fulfilling power requirements and coming from a minimal input parameter set.

An important aspect is the developed concept for user-driven design work with PrEDiCT involving an interactive GUI and a built-in execution mode called ‘ReDesign’ that retains the design code nature of the program with geometry output, but still allows for effective evolution and tailoring of the global design down to each stage and blade row. The paper closes with the validation and results section, which highlights three examples where the code is applied to axial turbine predesign and research.

The intention of this paper is to encourage the use of early predesign methods even by non-OEM organizations, since the presented work has shown for DLR multiple benefits in terms of research work, cooperation with other departments and OEM industry as well as training of personnel. Furthermore the implementation of PrEDiCT facilitated the transition from pre- to detailed design (i.e. 3D CFD) to such an extent, that the still important role of 2D throughflow methods could be questioned, i.e. being less relevant in the future for some design tasks.
Reynolds Stress Anisotropy in a Two-Stage Low Pressure Axial Turbine at Low Reynolds Numbers
Authors: Habermann Jan , Arenz Martin C. , Staudacher Stephan , Rose Martin G. , Guendogdu Yavuz , Raab Irene
Published: September 2016

Computational fluid dynamics have become important in turbine design, because experimental tests can easily become very expensive and time consuming. The industrially used two-equation turbulence models have weaknesses in predicting the Reynolds stress anisotropy in complex flows. The free stream Reynolds stresses influence transition and separation on turbine airfoils and vice versa. Higher-order models are supposed to improve numerical prediction quality. For development and validation of these models, a good understanding of the Reynolds stress distribution is required. Therefore the full Reynolds stress tensor and its anisotropy are experimentally investigated in a two-stage low pressure axial turbine. The Reynolds stresses are resolved from 3D hot-film probe area traverses downstream of the first vane at three Reynolds numbers from 40,000 to 180,000, related to vane 1. Surface thin film gauge measurements on the suction side of the vane are used to determine transition and separation. The size of the separation bubble on the late suction side and the progress of transition vary with Reynolds number. This influences the Reynolds stress elements to different extents and thus the Reynolds stress anisotropy downstream of the vane.
Effects of Freestream Mach Number, Reynolds Number, and Boundary Layer Thickness on Film Cooling Effectiveness of Shaped Holes
Authors: Anderson Joshua B. , Wilkes Ellen K. , McClintic John W. , Bogard David G.
Published: September 2016

Film cooling effectiveness can be greatly affected by the characteristics of the upstream approach flow, although the degree of influence that different approach flow parameters exert is not completely clear. While some recent studies have investigated the effect of the approach Mach number, very little data exists that describes the separate effects of approach Mach and Reynolds number. Furthermore, the effect of boundary layer thickness on the effectiveness of shaped holes has not been thoroughly investigated. In this work, a parametric study of these effects was undertaken. This study considered approach flow velocities of Ma∞ = 0.03–0.15, with an independently varied Reynolds number of ReD = 5,500 – 15,500 by utilizing cooling hole diameters of D = 4.0 mm and 9.0 mm. The influence of boundary layer properties, including laminar and turbulent approach boundary layer characteristics, as well as varying boundary layer thickness, was also investigated. This work utilized plenum-fed shaped holes of an open-literature design. Hi-resolution IR thermography measured adiabatic effectiveness downstream of a single row of shaped cooling holes. The experiments were conducted at a density ratio of DR = 1.80 with an ambient temperature approach flow, using blowing ratios varying from M = 1.0 to 3.0. Special attention was paid to the implications of these results for scaling of effectiveness measurements from lower-speed approach flow conditions, as is present in a laboratory, toward higher speed conditions present within a gas turbine engine.
Structure of Diffuser Stall and Unsteady Vortices in a Centrifugal Compressor With Vaned Diffuser
Authors: Fujisawa Nobumichi , Ikezu Sota , Ohta Yutaka
Published: September 2016

The characteristics of a diffuser rotating stall and the evolution of a vortex generated on the diffuser leading edge (i.e., leading-edge vortex (LEV)) in a centrifugal compressor were investigated using experiments and numerical analyses. The experimental results showed that both impeller and diffuser rotating stalls occurred at 55 and 25 Hz during off-design flow operation. Both the stall cells existed only on the shroud side of the flow passages, which is in close proximity to the source location of the LEV. The numerical results showed that the LEV is a combination of a separated vortex near the leading edge and the extended tip-leakage flow from the impeller. In the partial flow operation, the LEV develops as the velocity decreases in the diffuser passages and forms a huge flow blockage within the diffuser passages. Therefore, the LEV may be considered to be one of the causes of diffuser stall in the centrifugal compressor.
Readings on Specific Gas Turbine Flame Behaviours Using an Industrial Combustion Monitoring System
Authors: Giuliani Fabrice , Reiss Hans , Stuetz Markus , Moosbrugger Vanessa , Silbergasser Alexander
Published: September 2016

The new energy mix places greater demands on power gas turbine operation; precision combustion monitoring, therefore has become a major issue. Unforeseen events such as combustion instabilities can occur and represent a danger to the integrity of the hot parts and also lead to a limitation of the output power. This is usually accompanied by an increase in maintenance costs. The enlarged off-design operating envelope of gas turbines to adapt to a fast-changing grid has made this issue even more acute, necessitating an expansion of the operating envelope into areas that were — for many engines — not foreseen in the original combustor design process. A good understanding of what happens within the gas turbine combustor is crucial. Complex and costly full-field measurements such as laboratory optical instrumentation in precision combustion diagnostics are not suitable for permanent fleet deployment. For practical and financial reasons, the monitoring should ideally be achieved with a limited amount of discrete sensors. If installed and interpreted correctly, fast response measurement chains could lead to a better gas turbine combustion management, possibly yielding considerable savings in terms of operating and maintenance costs. The firm Meggitt Sensing System (MSS), assisted by Combustion Bay One (CBOne), initiated an applied research programme dedicated to this topic — with MSS providing the instrumentation and CBOne providing the facility and test conditions. The objective was to investigate realistic combustion phenomena in a precisely controlled and reproducible way and to document the individual readings of the heat-resistant fast pressure transducers mounted on the combustor casing, as well as the accelerometers mounted on the outer surface of the machine. Particular attention was paid to the correlation between these two types of sensor readings. This paper reports on the monitoring of the flame using piezoelectric dynamic pressure sensors and accelerometers in a number of different situations that are relevant to the safe and efficient operation of gas turbines. Discussed are single events such as flame ignition, lean blow-out and flash-back, as well as longer test sequences observing the effect of warming-up or the presence of flame instability. The measurement chains and processing techniques are discussed in detail. The atmospheric test rig used for this purpose and the different testing configurations required for each of these situations are also illustrated in detail. The results and recommendations for their implementation in an industrial context conclude this paper.