bluuebunny/crossref_metadata_2025 huggingface dataset:
The Association of Maternal Age with Birthweight and Gestational Age: A Cross‐Cohort Comparison
Authors: Restrepo‐Méndez María Clara , Lawlor Debbie A. , Horta Bernardo L. , Matijasevich Alicia , Santos Iná S. , Menezes Ana M. B. , Barros Fernando C. , Victora Cesar G.
Published: November 2014

Background

We examined the associations of maternal age with low birthweight (LBW) and preterm birth in four cohorts from a middle‐ and a high‐income country, where the patterning of maternal age by socio‐economic position (SEP) is likely to differ.

Methods

Population‐based birth cohort studies were carried out in the city of Pelotas, Brazil in 1982, 1993, and 2004, and in Avon, UK in 1991 [Avon Longitudinal Study of Parents and Children (ALSPAC)]. Adjustment for multiple indicators of SEP were applied.

Results

Low SEP was associated with younger age at childbearing in all cohorts, but the magnitudes of these associations were stronger in ALSPAC. Inverse associations of SEP with LBW and preterm birth were observed in all cohorts. U‐shaped associations were observed between maternal age and odds of LBW in all cohorts. After adjustment for SEP, increased odds of LBW for young mothers (<20 years) attenuated to the null but remained or increased for older mothers (≥35 years). Very young (<16 years) maternal age was also associated with both outcomes even after full SEP adjustment. SEP adjusted odds ratio of having a LBW infant in women <16 years and ≥35 years, compared with 25–29 years, were 1.48 [95% confidence interval (CI) 1.00, 2.20] and 1.66 [95% CI 1.36, 2.02], respectively. The corresponding results for preterm birth were 1.80 [95% CI 1.23, 2.64)] and 1.38 [95% CI 1.15, 1.67], respectively.

Conclusion

Confounding by SEP explains much of the excess risk of LBW and preterm among babies born to teenage mothers as a whole, but not for mothers aged <16 or ≥35 years. Given that the proportion of women becoming pregnant at <16 years is smaller than for those ≥35 years, the population burden is greater for older age.
Heavy Fuel: Trade and Environment in the GATT/WTO Case Law
Authors: Cosbey Aaron , Mavroidis Petros C.
Published: November 2014

This article discusses the evolution of case law regarding the treatment of cases that the authors qualify as ‘trade and environment’ in the case law of the General Agreement on Tariffs and Trade (GATT) and the World Trade Organization (WTO). The main argument is that, as in many domestic jurisdictions, GATT/WTO courts moved from an original ‘hostile’ position towards environmental protection that incidentally affected trade flows to a more nuanced, even friendly attitude towards those measures that were legitimately ‘green’. WTO courts, like other courts before them, saw the signs of times. They did not have to ‘make’ law, though, in order to change their attitude towards environmental concerns. They only had to correct a clear mistake they committed in the late 1980s in the notorious tuna‐dolphin dispute, and start interpreting the GATT/WTO as it was meant to be by its framers: societal preferences, to the extent they are non‐discriminatory, trump obligations to liberalize trade.
Water Footprint Labelling and WTO Rules
Authors: Manson Laura , Epps Tracey
Published: November 2014

A water footprint is a concept that measures the total volume of freshwater used to produce a product, measured over the full supply chain. This article discusses one idea that has been mooted to ameliorate impending freshwater shortages – namely to encourage consumers to purchase products with a low water footprint by using a water footprint label. A label may provide sufficient incentive for consumers, and governments may impose measures such as taxes or import restrictions based on the water footprint. The article explores the international trade law implications of such measures and finds that, as with other areas of environmental regulation, international trade liberalization and the protection of sustainable freshwater resources are not incompatible goals. However, water footprint labelling, and other associated measures, could have inadvertent trade law implications, meaning that it will be important for governments to give careful thought to their design and application.
The impact of drug‐resistant cytomegalovirus in pediatric allogeneic hematopoietic cell transplant recipients: a prospective monitoring of UL97 and UL54 gene mutations
Authors: Choi S.‐H. , Hwang J.‐Y. , Park K.‐S. , Kim Y. , Lee S.H. , Yoo K.H. , Kang E.‐S. , Ahn J.‐H. , Sung K.W. , Koo H.H. , Kim Y.‐J.
Published: November 2014

Background

Cytomegalovirus (CMV) infection is a major cause of morbidity in allogeneic hematopoietic cell transplant (alloHCT) recipients. Little is known about the epidemiology of antiviral resistance in the pediatric population. We performed the prospective study to assess the impact of drug‐resistant CMV infections in pediatric alloHCT recipients.

Methods

Pediatric alloHCT recipients who developed CMV infection were consecutively enrolled from May 2009 to April 2012. CMV polymerase chain reaction amplification and sequencing analysis for UL97 and UL54 genes were performed at enrollment and during follow‐up.

Results

In total, 208 sequence data from viruses in 49 recipients were eligible for the final analysis. Resistant CMV infection caused by UL97 and UL54 mutations occurred in 4.1% (2/49) and 2.0% (1/49), respectively. Known UL97 mutations, M460V and C592G, were observed in each of 2 patients. One patient with the M460V UL97 mutation had an additional T700A UL54 mutation. Drug‐resistant CMV attributable mortality was 2.0% (1/49). One or more known sequence variants (drug‐sensitive) were observed in all 49 patients. Thirty‐one (63.3%) and 28 patients (60.9%) already had known UL97 and UL54 sequence variants before antiviral therapy, respectively.

Conclusion

This study provides comprehensive information on the epidemiology of both UL97 and UL54 variants and mutations in alloHCT recipients.
SAD1, an RNA polymerase I subunit A34.5 of rice, interacts with Mediator and controls various aspects of plant development
Authors: Li Weiqiang , Yoshida Akiko , Takahashi Megumu , Maekawa Masahiko , Kojima Mikiko , Sakakibara Hitoshi , Kyozuka Junko
Published: November 2014

The DWARF14 (D14) gene of rice functions within the signaling pathway of strigolactones, a group of plant hormones that inhibits shoot branching. We isolated a recessive mutant named super apical dormant (sad1‐1) from a suppressor screen of d14‐1. The growth of tillers (vegetative shoot branches) is suppressed in both the d14‐1 sad1‐1 double mutant and the sad1‐1 single mutant. In addition, the sad1‐1 mutant shows pleiotropic defects throughout development. SAD1 encodes an ortholog of RPA34.5, a subunit of RNA polymerase I (Pol I). Consequently, the level of ribosomal RNA (rRNA) is severely reduced in the sad1‐1 mutant. These results indicate that proper ribosome function is a prerequisite for normal development in plants. The Arabidopsis ortholog of SAD1 was previously isolated as a Mediator‐interacting protein. Here we show that SAD1 interacts physically with the Mediator complex through direct binding with OsMED4, a component of the middle module of the Mediator complex in rice. It is known that Mediator interacts with Pol II, which transcribes mRNAs and functions as a central regulator of transcription. This study indicates a novel aspect of Mediator function in Pol I‐controlled rRNA transcription. TFIIF2 and RPC53 are the counterparts of RPA34.5 in Pol II and Pol III, respectively. We demonstrate that the rice orthologs of these proteins also interact with OsMED4. Our results suggest that interaction with MED4 in the Mediator complex is a common feature of the three types of RNA polymerases.
Arabidopsis DOK1 encodes a functional dolichol kinase involved in reproduction
Authors: Kanehara Kazue , Cho Yueh , Lin Ying‐Chen , Chen Chia‐En , Yu Chao‐Yuan , Nakamura Yuki
Published: November 2014

Dolichol phosphate (Dol‐P) serves as a carrier of complex polysaccharides during protein glycosylation. Dol‐P is synthesized by the phosphorylation of dolichol or the monodephosphorylation of dolichol pyrophosphate (Dol‐PP); however, the enzymes that catalyze these reactions remain unidentified in Arabidopsis thaliana. We performed a genome‐wide search for cytidylyltransferase motif‐containing proteins in Arabidopsis, and found that At3g45040 encodes a protein homologous with Sec59p, a dolichol kinase (DOK) in Saccharomyces cerevisiae. At3g45040, designated AtDOK1, complemented defects in the growth and N‐linked glycosylation of the S. cerevisiae sec59 mutant, suggesting that AtDOK1 encodes a functional DOK. To characterize the physiological roles of AtDOK1 in planta, we isolated two independent lines of T‐DNA‐tagged AtDOK1 mutants, dok1‐1 and dok1‐2. The heterozygous plants showed developmental defects in male and female gametophytes, including an aberrant pollen structure, low pollen viability, and short siliques. Additionally, the mutations had incomplete penetrance. These results suggest that AtDOK1 is a functional DOK required for reproductive processes in Arabidopsis.
A VALENTINE‐SHAPED CARDIAC SILHOUETTE IN FELINE THORACIC RADIOGRAPHS IS PRIMARILY DUE TO LEFT ATRIAL ENLARGEMENT
Authors: Oura Trisha J. , Young Aisha N. , Keene Bruce W. , Robertson Ian D. , Jennings Dennis E. , Thrall Donald E.
Published: November 2014

Conflicting information has been published regarding the cause of a valentine‐shaped cardiac silhouette in dorsoventral or ventrodorsal thoracic radiographs in cats. The purpose of this retrospective, cross‐sectional study was to test the hypothesis that the valentine shape is primarily due to left atrial enlargement. Images for cats with a radiographic valentine‐shaped cardiac silhouette and full echocardiography examination were retrieved and independently reviewed. A subjective scoring system was used to record severity of radiographic valentine shape. Subjective radiographic evidence of left atrial enlargement in a radiographic lateral projection and a final diagnosis based on medical records were also recorded. A total of 81 cats met inclusion criteria. There was a strong positive correlation (P < 0.001) between echocardiographic left atrial size and severity of radiographic valentine shape. There was no effect of echocardiographic right atrial size on the severity of valentine shape, except when concurrent with severe left atrial enlargement. In this situation, right atrial enlargement increased the likelihood of observing a severe valentine shape. There was no effect of right atrial enlargement on the shape of the cardiac silhouette when left atrial enlargement was absent or only mild to moderate. There was no correlation between the category of final diagnosis of cardiac disease and the severity of valentine shape. Findings from this study supported the hypothesis that a valentine‐shaped cardiac silhouette in radiographs is due primarily to left atrial enlargement in cats, with right atrial enlargement only impacting the shape if concurrent with severe left atrial enlargement.
DIVINE GLORY IN A DARWINIAN WORLD
Authors: Southgate Christopher
Published: November 2014

Faced with the ambiguities of this world, in which ugliness and suffering co‐exist with beauty, the article rejects the attribution of disvalues to a Fall‐event. Instead it faces God's involvement even in violence and ugliness. It explores the concept of divine glory, understood principally as a sign of the divine reality. This includes both the great theophanies of the Hebrew Bible and Jesus’ glorification in his Passion and Crucifixion. It then considers the contemplation of the natural world, using the terminology of “inscape” and “instress.” Divine glory can be discerned even in events as tragic as the Indian Ocean tsunami or the activity of the malarial mosquito. A full Christian contemplation of these events will include scientific understanding and poetic apprehension, and consideration of soteriology and eschatology as well as the theology of creation. Glory is understood to include God's power and sovereignty, and also the divine humility and sacrifice.
CHALLENGES TO THE TRADITIONAL CHRISTIAN CONCEPT OF HISTORY
Authors: Henriksen Jan‐Olav
Published: November 2014

Present knowledge of evolutionary history challenges traditional concepts of the Christian salvation history. In order to overcome these challenges, theology needs to articulate a wider, more open and more universal approach to the understanding of God's salvific action. One way of doing this is to employ the notion of “deep incarnation” suggested by Danish theologian Niels Henrik Gregersen. His suggestion may also blur the lines that mark a sharp distinction between the history of creation and the history of salvation, in a way that safeguards some of the basic tenets of classical theology.
VALUING OUR FOOD: MINIMIZING WASTE AND OPTIMIZING RESOURCES
Authors: Finn Steven M.
Published: November 2014

The magnitude of the global food waste problem is staggering, yet it receives little mainstream attention. We waste nearly half of all food produced—more than one billion tons annually—yet nearly one billion global citizens are hungry. Our values are out of balance; we need to properly value our food. Urgent change is needed, beginning with heightened awareness and a sense of responsibility to people and planet.

Feeding nine billion people by 2050 is a tremendous challenge, but also a tremendous opportunity to develop new levels of innovation and collaboration to eradicate hunger, improve the environment for future generations, and create a more unified, secure world.

A new, durable, multifaceted approach to reducing food waste is needed in the form of a global network. This global network should be anchored by a sense of shared responsibility among consumers, businesses, governments, and global institutions to optimize resources in the quest to provide for nine billion people by 2050.
WHY WE NEED RELIGION TO SOLVE THE WORLD FOOD CRISIS
Authors: Whitney Sanford A.
Published: November 2014

Scholars and practitioners addressing the global food crisis have rarely incorporated perspectives from the world's religious traditions. This lacuna appears in multiple dimensions: until recently, environmentalists have tended to ignore food and agriculture; food justice advocates have focused on food quantities, rather than its method of production; and few scholars of religion have considered agriculture. Faith‐based perspectives typically emphasize the dignity and sanctity of creation and offer holistic frameworks that integrate equity, economic, and environmental concerns, often called the three legs of sustainability. Faith‐based perspectives can provide new paradigms through which to assess food, consumption, and production and the attendant social relations; assess our scientific, economic, and social approaches; and acknowledge the moral and religious dimensions of the world food crisis.
FOOD: ITS MANY ASPECTS IN SCIENCE, RELIGION, AND CULTURE
Authors: Raman Varadaraja V.
Published: November 2014

Food is a sine qua non for life on Earth. It has more significance than nutrition and sustenance, more variety than many aspects of human culture. Food has religious as well as historical dimensions. The complexity of the food chain and of the related ecological balance is one of the wonders of the biological world. In the human context, food has found countless expressions and regional richness. Food has provoked feasts, as its lack and maldistribution have caused famines. While being a source of physical satisfaction food has also had environmental impacts. Some of these matters are explored in these reflections.
UNCERTAINTY AND GOD: A JAMESIAN PRAGMATIST APPROACH TO UNCERTAINTY AND IGNORANCE IN SCIENCE AND RELIGION
Authors: Petersen Arthur
Published: November 2014

This article picks up from William James's pragmatism and metaphysics of experience, as expressed in his “radical empiricism,” and further develops this Jamesian pragmatist approach to uncertainty and ignorance by connecting it to phenomenological thought. The Jamesian pragmatist approach avoids both a “crude naturalism” and an “absolutist rationalism,” and allows for identification of intimations of the sacred in both scientific and religious practices—which all, in their respective ways, try to make sense of a complex world. Analogous to religious practices, emotion and the metaphysics of experience play a central role in science, especially the emotion of wonder. Engaging in scientific or religious practices may create opportunities for individuals to realize that they are co‐creators of the world in partnership with God, in full awareness of uncertainty and ignorance and filled with the emotion of wonder.
Impact of Cooling Injection on the Transonic Over-Tip Leakage Flow and Squealer Aerothermal Design Optimization
Authors: Wang Z. , Zhang Q. , Liu Y. , He L.
Published: November 2014

In the present work, the effect of coolant injection on the over-tip-leakage (OTL) flow and squealer designs has been investigated in a transonic flow regime. After an experimental verification of the computational tool adopted for capturing transonic flow characteristics, a series of quasi-three-dimensional (3D) computational analyses were carried out to reveal and understand the cooling jet—OTL flow interaction at various hole locations and inclination angles. The results indicate that the performance rankings between flat tip and squealer tip designs might be altered by the addition of cooling injection. Full 3D conjugate heat transfer analyses demonstrate that partially replacing the squealer cavity with a simple flat shaped configuration in the rear transonic flow portion would offer a much improved coolability without paying extra aerodynamic penalty.
Geometric Mistuning Reduced-Order Models for Integrally Bladed Rotors With Mistuned Disk–Blade Boundaries
Authors: Beck Joseph A. , Brown Jeffrey M. , Kaszynski Alex A. , Cross Charles J. , Slater Joseph C.
Published: November 2014

New geometric mistuning modeling approaches for integrally bladed rotors (IBRs) are developed for incorporating geometric perturbations to a fundamental disk–blade sector, particularly the disk–blade boundary or connection. Reduced-order models (ROMs) are developed from a Craig–Bampton component mode synthesis (C–B CMS) framework that is further reduced by a truncated set of interface modes that are obtained from an Eigen-analysis of the C–B CMS constraint degrees of freedom (DOFs). An investigation into using a set of tuned interface modes and tuned constraint modes for model reduction is then performed, which offers significant computational savings for subsequent analyses. Two configurations of disk–blade connection mistuning are investigated: as-measured principal component (PC) deviations and random perturbations to the interblade spacing. Furthermore, the perturbation sizes are amplified to investigate the significance of incorporating mistuned disk–blade connections during solid model generation from optically scanned geometries. Free and forced response results are obtained for each ROM and each disk–blade connection type and compared to full finite element model (FEM) solutions. It is shown that the developed methods provide accurate results with a reduction in solution time compared to the full FEM. In addition, results indicate that the inclusion of a mistuned disk–blade connection deviations are small or conditions where large perturbations are localized to a small areas of the disk–blade connection.
Vibroacoustic Comparisons and Acoustic Power Insulation Mechanisms of Multidirectional Stiffened Laminated Plates
Authors: Cao Xiongtao , Hua Hongxing
Published: November 2014

Vibroacoustic characteristics of multidirectional stiffened laminated plates with or without compliant layers are explored in the wavenumber and spatial domains with the help of the two-dimensional continuous Fourier transform and discrete inverse fast Fourier transform. Implicit equations of motion for the arbitrary angle ply laminated plates are derived from the three-dimensional higher order and Reddy third order shear deformation plate theories. The expressions of acoustic power of the stiffened laminated plates with or without complaint layers are formulated in the wavenumber domain, which is a significant method to calculate acoustic power of the stiffened plates with multiple sets of cross stiffeners. Vibroacoustic comparisons of the stiffened laminated plates are made in terms of the transverse displacement spectra, forced responses, acoustic power, and input power according to the first order, Reddy third order, and three-dimensional higher order plate theories. Sound reduction profiles of compliant layers are further examined by the theoretical deductions. This study shows the feasibility and high efficiency of the first order and Reddy third order plate theories in the broad frequency range and allows a better understanding the principal mechanisms of acoustic power radiated from multidirectional stiffened laminated composite plates with compliant layers, which has not been adequately addressed in its companion paper. (Cao and Hua, 2012, “Sound Radiation From Shear Deformable Stiffened Laminated Plates With Multiple Compliant Layers,” ASME J. Vib. Acoust., 134(5), p. 051001.)
Diffusion Bonded Heat Exchangers (PCHEs) in Fuel Gas Heating to Improve Efficiency of CCGTs
Authors: Shiferaw Dereje , Broad Robert
Published: November 2014

The purpose of this paper is to show how compact heat exchanger technology can offer energy savings and hence cycle efficiency improvements on new and existing gas turbine installations by being utilised for fuel gas heating.

After a brief introduction to high temperature compact heat exchanger technology and comparison to traditional equipment, thermodynamic cycle analysis for a combined cycle gas turbine plant (CCGT) is used show the advantages of compact technology over conventional technology, analysing the fuel gas heating, to illustrate the overall savings. A case study is used to demonstrate an increase in net LHV electric efficiency in the range of 0.5 to 1.17 % achievable using high effectiveness compact diffusion bonded heat exchangers in fuel gas heating. Intermediate pressure and high pressure feed water heating is considered for increasing the fuel gas inlet temperature to the combustor. The model is built in Excel and is extended to a capital expenditure overview based on new or a retrofitting in existing plants.
Assessment of the Combustion Behavior of a Pilot-Scale Gas Turbine Burner Using Image Processing
Authors: De Giorgi Maria Grazia , Sciolti Aldebara , Campilongo Stefano , Ficarella Antonio
Published: November 2014

Experimental investigations were performed on a non-premixed liquid fuel-lean burner. The present work aims to the development of a methodology for the recognition of flame instability regimes in industrial and aeronautical burners. Instability, in fact, is an unpleasant aspect of combustive system that negatively impacts on combustion efficiency. The online monitoring of the occurrence of instability conditions, permits to adjust combustion parameters (as fuel or air mass flow, temperature, pressure, etc.) and to stabilize again the flame.

High speed visualization systems are promising methods for on-line combustion monitoring.

In this study two high speed visualization systems in the visible range and in the infrared spectral region were applied to characterize combustion efficiency and flame stability.

Different processing techniques were used to extract representative data from flame images.

Wavelet Decomposition and Spectral analysis of pixel intensities of flame images were used for feature extraction. Finally a statistical analysis was performed to identify the most unstable regions of the flame by the pixel intensity variance.
Selection of Biomass Feedstock for Production of Biocoal for Coal-Fired Boilers
Authors: Mody Jaisen , Saveliev Roman , Bar-Ziv Ezra , Perelman Miron
Published: November 2014

PGE in collaboration with EBC and MTU is carrying out a testing program to fire up to 100% of biocoal (torrefied biomass) in its 600 MW Boardman boiler. An important aspect of this program is the selection of suitable biomass feedstock from which biocoal will be produced, emphasizing potential problems of fouling and slagging in the boiler. We thoroughly tested seven different types of feedstock: Arundo Donax (AD), wheat waste, corn waste, woody hybrid poplar, and bark from hybrid poplar, woody pine, and bark from pine. It was found that all these material comprised significant amounts of soil (varying from 5–25% in weight) with low fusion temperatures and therefore must be avoided from flowing into the boiler. We developed a separation technology of the soil from the biomass and were able to obtain biomass feedstock only with the plant minerals. All separated biomass feedstock, from soil, showed mineral content that is respective to soil they grew at. Samples were characterized for ultimate and proximate analysis, ash content and analysis and fusion temperatures. AD, wheat, and corn showed high content of potassium and low flow temperatures and therefore may not be used at 100% firing test unless some of the mineral contents are removed to protect the boiler from corrosion and slagging. Woody and bark hybrid poplar were found to have high fusion temperatures; woody and bark pine showed flow temperatures around 2500°F. All four feedstock types can be used for 100% firing test, however, the ones which is mostly recommended are woody and bark hybrid poplar.
Implementation of Expert System Modeling to Thermal-Hydraulic Design of Hydraulic Systems
Authors: Tarrad Ali H. , Al-Baldawi Rafea A. , Al-Issa Ahmad A.
Published: November 2014

Thermal and hydrodynamic concepts are of a vital importance; therefore their assessments are unavoidable for the purpose of hydraulic systems. The present study implements the practical updated knowledge of the expertise for both of the hydraulic and thermal fields in an expert system model. This is implemented in order to improve the performance of hydraulic system by considering the thermal effect on the hydraulic system operation. Accordingly, a computer program (Hydraulic System Calculations), designated as (HSC) implements a Visual Basic language in the Microsoft Visual Studio 2010 software has been built. Regardless of the design requirements, the code is capable to deal with (18) possible connection types of the actuators, in series or parallel, arrangements. The suggested code provides the designer with a number of choices, different kind of connections, to resolve the problem of hydraulic oil overheating which may arise during the continuous operation of the hydraulic unit. As a result, the (HSC) is able to minimize the human errors, effort, time and cost of hydraulic machine design.
Standardization of Cross Flow Turbine Design for Typical Micro-Hydro Site Conditions in Pakistan
Authors: Chattha J. A. , Khan M. S. , Iftekhar H. , Shahid S.
Published: November 2014

Pakistan has a hydro potential of approximately 42,000MW; however only 7,000MW is being utilized for electrical power production [1, 2]. Out of 42,000 MW, micro hydro potential is about 1,300MW [1, 2]. For typical site conditions (available flow rate and head) in Pakistan, Cross Flow Turbines (CFTs) are best suited for medium head 5–150m [3] for micro-hydro power production. The design of CFT generally includes details of; the diameter of the CFT runner, number of blades, radius of curvature and diameter ratio. This paper discusses the design of various CFTs for typical Pakistan site conditions in order to standardize the design of CFTs based on efficiency that is best suited for a given site conditions. The turbine efficiency as a function of specific speed will provide a guide for cross flow turbine selection based on standardized turbine for manufacturing purposes. Standardization of CFT design will not only facilitate manufacturing of CFT based on the available site conditions with high turbine efficiency but also result in reduced manufacturing cost.
Multi-Criteria Analysis, Evaluation and Modeling of Future Scenario for the Energy Generation Sector — A Case Study
Authors: Mirmohammadi Seyed Aliakbar , Behi Mohammad Reza , Suma Alexander B. , Palm Björn E.
Published: November 2014

Renewable energy continues to attract much interest due to the depletion of fossil fuels and unsettled political disputes. This study aims to evaluate the current status of energy generation on the campus of Eindhoven University of Technology (TU/e). Furthermore, it looks for ways for the TU/e to improve sustainability by finding and proposing alternative solutions. Therefore, a broad scope of various renewable energy sources (RES) has been investigated. From many aspects, the analysis of RES proves that biomass is the most appropriate source of renewable energy for the TU/e campus. Thus, the capability of harvestable biomass fuel in energy generation throughout a year has been investigated for this project, and it has been concluded that solid biomass waste from the campus can provide 1314 MWh heat load annually. In order to achieve as much energy from biomass as possible, a combined heat and power unit (CHP), in order to produce both heat and electricity for new student houses on the campus, has been modeled. Finally, the project results show that a small-scale CHP cycle is capable of producing 366 MWh electricity, as well as 772 MWh heat, annually.
Numerical Simulation of a Compressed Air Driven Tesla Turbine
Authors: Siddiqui M. Salman , Ahmed Humza , Ahmed Shaheer
Published: November 2014

This paper presents the Computational Fluid Dynamics analysis of a Tesla bladeless turbine using compressed air as the working fluid. Multiple flow configurations are analyzed using both Laminar and the turbulent behaviors. The loading coefficient and the efficiency of turbines is evaluated for both the 2D and 3D cases. Multiples disc is a viable option but it is been observed they result in loss in performance for the laminar and turbulent simulations. In addition the inflection point of the laminar flow vanishes in the turbulent flow; the work presented is an initial step towards the realization of Tesla turbine.
Effects of Increased PRB Coal Consumption on the Aerodynamic Stability of Induced Draft Fans
Authors: Washington DeVon A. , Lewis James B.
Published: November 2014

This study examines the upgrade of two forward-curved centrifugal induced draft fans, to support fuel blends with greater fractions of PRB coal for a 160 MWe generating unit. After a post installation event, an audible periodic low frequency vibration in the breeching was noticed at loads ranging from 75–95 MWe. A detailed investigation was conducted which included fluid dynamic and vibration analyses of the fan and system, as well as an assessment of the fan and motor performance characteristics.

Results of the analyses revealed system resistances which generated operating points in the stall region on the fan performance curve. Non-uniform fan inlet flow distributions were characterized by axial and transverse distortion parameters. Data showed relatively high transverse distortion parameters over the affected load range with the maximum of 20.5% distortion occurring at 95 MWe; with a corresponding breeching vibration frequency approximately four-thirds shaft speed.

Based on the data obtained and observed system behavior, it was determined the phenomenon responsible for the flow-induced vibration was the onset of rotating stall. The magnitude of the pressure pulses associated with this low frequency vibration is capable of causing fatigue damage to large ductwork and producing unwanted acoustic emissions. In light of the large number of similar conversions performed throughout industry and increases in partial-load operation, the accurate diagnosis of such phenomenon is vital for reliable plant operations. This work summarizes an effective and practical methodology for making such evaluations, while addressing issues of fan performance and system effects.
Understanding the Reactive Power Problem and a Mechanical Solution Using Peaking or Retired Generators
Authors: Attix Randall M. , Chamberlin D. M.
Published: November 2014

Reactive power is an unwanted but unavoidable part of alternating current electric power delivery systems. Governed by the laws of physics, it occurs due to the inherent nature of the components of these systems. This article develops an understanding of reactive power and the control of it to reduce its adverse effects and to improve the efficiency of an electric power delivery system.

The article begins by identifying and representing electric power circuit components, real power, and reactive power. These are then mathematically shown how they interact and affect the power delivery system.

Control and mitigation of the effects of reactive power are then developed with emphasis on mechanical solutions using rotating machines. In particular, peaking or retired generators are identified for use as rotating condensers as well as new installations. A description of the gear type synchronous self-synchronizing (SSS) overrunning clutches used to connect and dis-connect a generator from the peaking prime mover or the retired generator from a starting system is included.
Design and Fabrication of an Experimental Facility for High-Pressure Pool Boiling
Authors: Li Nanxi , Betz Amy Rachel
Published: November 2014

In this work, we present the design and fabrication a high-pressure pool boiling facility to conduct pool boiling experiments on horizontal heated surfaces under elevated pressures, up to 20 bar. Previous research has shown that micro- and/or nano-structured surfaces and coated surfaces will increase heat transfer coefficients up to one order of magnitude at atmospheric pressure. However, most boiling applications are subjected to high pressure, especially in the power industry. Pressure inside a boiling water reactor in a nuclear power plant will reach as high as 75 atm (75.99 bar). In order to determine how heat transfer is enhanced at increased pressures, with deionized water and refrigerants, on modified surfaces, a special experimental setup needs to be designed and fabricated. Difficulties in making such an experimental setup come from stabilizing the system pressure, sealing the test setup and visualizing the boiling conditions in the vessel. Both advantages and disadvantages of this design will be discussed and possible methods for improvements will be proposed. Preliminary test results on a plane copper surface are also included. Future research will be focusing on boiling of water and refrigerants on micro-structured copper surfaces, graphene coated, and Teflon© coated surfaces under high pressure.
Alstom Desuperheater Addition to We Energies Oak Creek Power Plant Units 5 and 6
Authors: Olson Terrence , Wade Doug , Gelbar Danny
Published: November 2014

We Energies Oak Creek Power Plant units 5 and 6 were designed and built with no main steam temperature control mechanism. We Energies wanted to add desuperheaters to the units and do so in the simplest and most cost effective manner. Previous proposed solutions were deemed too expensive or potentially unreliable. The selected option from Alstom Power utilized the unique design elements of the boilers and offered up the temperature control required. The new desuperheater system has positively affected plant startup and normal operation of these boilers.
Low Emissions Microgrid Power Fueled by Bakken Flare Gas
Authors: Roby Richard J. , Holton Maclain M. , Klassen Michael S. , Eskin Leo D. , Joklik Richard J. , Broemmelsiek Christopher
Published: November 2014

It is estimated that 30% of the over 1 billion cubic feet per day of natural gas produced in the Bakken shale field is lost to flaring. This flared gas, were it to be collected and used in DLE power generation gas turbine engines, represents approximately 1.2 GW of collective electric power. The main reason that much of this gas is flared is that the infrastructure in the Bakken lacks sufficient capacity or compression to combine and transport the gas streams. One of the reasons that this gas cannot be utilized on-site for power generation is that it contains significant amounts of natural gas liquids (NGLs) which make the gas unsuitable as a fuel for natural gas-fired gas turbine engines. A Lean, Premixed, Prevaporized (LPP) combustion technology has been developed that converts liquid fuels into a substitute for natural gas. This LPP Gastm can then be used to fuel virtually any combustion device in place of natural gas, yielding emissions comparable to those of ordinary natural gas. The LPP technology has been successfully demonstrated in over 1,000 hours of clean power generation on a 30 kW Capstone C30 microturbine. To date, 15 different liquid fuels have been vaporized and burned in the test gas turbine engine. To simulate the vaporization of NGLs, liquids including propane, pentane, and naphtha, among other liquids, have been vaporized and blended with methane. Emissions from the burning of these vaporized liquid fuels in the test engine have been comparable to baseline emissions from ordinary natural gas of 3 ppm NOx and 30 ppm CO. Autoignition of the vaporized liquid fuels in the gas turbine is controlled by the fraction of inert diluent added in the vaporization process. The LPP technology is able to process an infinitely variable composition of NGL components in the fuel stream by continually adjusting the amount of dilution to maintain a heating value consistent with natural gas. Burning the flare gases containing NGLs from a well locally, in a power generation gas turbine, would provide electricity for drilling operations. A microgrid can distribute power locally to the camps and infrastructure supporting the drilling and processing operations. Using the flare gases on-site has the benefit of reducing or eliminating the need for diesel tankers to supply fuel for power generation systems and equipment associated with the drilling operations.
3D CFD Simulations of a Candidate R143A Radial-Inflow Turbine for Geothermal Power Applications
Authors: Sauret Emilie , Gu Yuantong
Published: November 2014

Optimisation of Organic Rankine Cycles (ORCs) for binary cycle applications could play a major role in determining the competitiveness of low to moderate renewable sources. An important aspect of the optimisation is to maximise the turbine output power for a given resource. This requires careful attention to the turbine design notably through numerical simulations. Challenges in the numerical modelling of radial-inflow turbines using high-density working fluids still need to be addressed in order to improve the turbine design and better optimise ORCs. This paper presents preliminary 3D numerical simulations of a radial-inflow turbine working with high-density fluids in realistic geothermal ORCs. Following extensive investigation of the operating conditions and thermodynamic cycle analysis, the refrigerant R143a is chosen as the high-density working fluid. The 1D design of the candidate radial-inflow turbine is presented in details. Furthermore, commercially-available software Ansys-CFX is used to perform preliminary steady-state 3D CFD simulations of the candidate R143a radial-inflow turbine at the nominal operating condition. The real-gas properties are obtained using the Peng-Robinson equations of state. The thermodynamic ORC cycle is presented. The preliminary design created using dedicated radial-inflow turbine software Concepts-Rital is discussed and the 3D CFD results are presented and compared against the meanline analysis.
Design and Optimization of Waste Heat Recovery Unit Using Carbon Dioxide as Cooling Fluid
Authors: Skaugen Geir , Walnum Harald T. , Hagen Brede A. L. , Clos Daniel P. , Mazzetti Marit J. , Nekså Petter
Published: November 2014

This paper describes design and optimization of a Waste Heat Recovery Unit (WHRU) for a power cycle which uses CO2 as a working fluid. This system is designed for offshore installation to increase gas turbine efficiency by recovering waste heat from the exhaust for production of additional power. Due to severe constraints on weight and space in an offshore setting, it is essential to reduce size and weight of the equipment to a minimum. Process simulations are performed to optimize the geometry of the WHRU using different objective functions and thermal-hydraulic models. The underlying heat exchanger model used in the simulations is an in-house model that includes the calculation of weight and volume for frame and structure for the casing in addition to the thermal-hydraulic performance of the heat exchanger core. The results show that the for a set of given process constraints, optimization with respect to minimum total weight or minimum core weight shown similar results for the total installed weight, although the design of heat exchanger differs. The applied method also shows how the WHRU geometry can be optimized for different material combinations.
Thermodynamic Analysis of an Integrated Solar-Based Cooling System in UAE
Authors: Gadalla Mohamed , Al Hammadi Amani
Published: November 2014

Renewable energy resource is considered by many developed and developing countries as a promising and a cost effective candidate to provide energy. The operation of cooling systems in the United Arab Emirates (UAE) have some operating problems especially in summer such as severe grid dependent, excessive energy consumption, high emissions and high costs. So, more economically and environmentally friendly HVAC systems are desired to provide the required electricity demands for cooling loads while saving energy and having low emissions to the environment. In this paper, a parabolic trough solar collector is integrated with a triple effect absorption cooling system for sustainable development. A computer code is developed using Engineering Equation Solver (EES) software to obtain all required thermodynamic properties of water-lithium bromide (H2O/LiBr) solution and to optimize all operating parameters and carry out all detailed energy and exergy analyses for a 10 kW cooling capacity. In addition, the parabolic trough solar collector (PTSC) is also designed for the required cooling load and its overall dynamic behavior is also investigated. The solar irradiance available in the UAE on a monthly basis is used in the analysis of a PTSC-based HVAC cooling system. Energetic and exergetic efficiencies of the PTSC for every month are also evaluated under different operating conditions. The Overall monthly energy and exergy efficiencies of the integrated PTSC-based HVAC system for a constant mass flow rate of Therminol-66 and concentration ratio are calculated. The dynamic variation of the coefficient of performance of the integrated system with the solar irradiance and mass flow rate of the oil are also evaluated. Results show that both energetic and exergetic COPs are decreased with increasing the solar irradiance for a constant mass flow rate of oil and constant concentration ratio. It is found that increasing the mass flow rate of the oil from 0.1 to 0.5 kg/s results in decreasing the energetic COP from 2.15 to 1.98 and the exergetic COP from 2.05 to 1.93.
Maintaining High Energy Piping Integrity With Unit Specific Strategic Planning
Authors: Hamblin-Smoske Pamela
Published: November 2014

High-energy piping systems are essential to the safe and cost-effective operation of power plants. The propensity for piping failures increases with the age of the systems involved. Prolonged operation, particularly at elevated temperatures, may result in metallurgical degradation which in-turn increases the potential for cracking and crack propagation until a final failure stage is reached by the component. As a result, power plant operators have become increasingly cognizant of the importance of condition assessment evaluations for high-energy piping systems.

Power plant operators are faced with specific challenges to maintain the integrity of their high energy piping systems including the reduction of onsite engineers, aging workforces, equipment, and the need to remain competitive in a challenging global energy market. Plant managers are routinely faced with the complex task of evaluating the current condition of their equipment, forecasting outage budgets and schedules, and performing risk assessments. Additionally, insurance companies are increasingly requiring inspection and maintenance records that are not always up-to-date or readily available.

The solution to strategically maintaining the integrity of high-energy piping systems involves taking a comprehensive approach to piping management utilizing unit specific operational training, advanced data management, strategic inspection, maintenance and replacement prioritization. Implementing this comprehensive approach has resulted in avoiding both catastrophic and leak type failures for plant managers that have adopted this strategy. Implementing a unit specific, targeted plan enables utility owners and operators to succeed in today’s competitive market by increasing the unit’s reliability and availability without sacrificing safety or environmental standards.

Thielsch Engineering, Inc. hosts over 30 years of advanced engineering experience and provides extensive services to more than 150 power plants each year. Our firm is also the creator and proprietary owners of the 4 SYTE System Strategies that is currently operating in more than 60 power plants throughout the U.S. and Canada. We are an employee-owned company with 425 partners who are dedicated to best practices and customer service is a priority. Thielsch has offices in Rhode Island, Ohio, Texas and Florida.
Reliability of Power Electric Systems in Pemex Refining: Experiences and Realities
Authors: Ruiz Flores Luis Ivan , Poujol Galván Francisco Cuauhtémoc
Published: November 2014

In this paper, we present the experience of 10 years of collaboration between the Electric Research Institute and Pemex Refining to modernize the power electric systems of the National Refining System in Mexico, collaborating together to design an electrical energy system for distribution that can operate reliably at the increase in the quantity and quality of oil products with the integration of new processing plants. We present the extensive cooperation between the personnel involved and in contrast unexecuted planning to implement the solutions. Also, after a decade of collaboration, we present the different scenarios, factors and challenges in the medium and long term that will assure that the electrical systems are in healthier conditions to operate for the next years and will achieve the required reliability of the national refining system for gasoline demand, to result in an operational reliability conferring to a World Class utility practice.